Peer-Reviewed Journal of the Academy of General Dentistry
GENERAL
DENTISTRY
March/April 2011 ~ Volume 59 Number 2
INFECTIOUS DISEASE CONTROL
TRAUMA IN PRIMARY/YOUNG TEETH
DENTINAL HYPERSENSITIVITY & TREATMENT
DIGITAL DENTAL PHOTOGRAPHY
CARIES DETECTION n WWW.AGD.ORG
Contents
Departments
86
Editorial Follow the money
88
Pharmacology Botulinum toxin (Botox, Dysport, and Myobloc):
Pharmacology 101
91
Restorative Dentistry Pre-prosthetic orthodontics for
esthetics and function in restorative dentistry
96
Dental Materials Latest innovations in flowable composites
152
Oral Diagnosis Interdental papilla overgrowth and Rubbery
palatal mass
154
Answers Oral Diagnosis and Self-Instruction exercises No. 255,
256, and 257
156
2010 reviewers list
Clinical articles
100
Infectious Disease Control Evaluation of the microbial flora
found in woodwind and brass instruments and their potential
to transmit diseases
R. Thomas Glass, DDS, PhD
Gerwald A. Kohler, PhD
110
Robert S. Conrad, PhD
James W. Bullard, MS
Oral Diagnosis What every dentist should know about zinc
Amar Patel, DDS
Nasir Bashirelahi, PhD
115
J. Anthony von Fraunhofer, MSc, PhD
Dentinal Hypersensitivity & Treatment Dentin
hypersensitivity and its management
C.H. Chu, BDS, MAGD, ABGD
Edward C.M. Lo, BDS, MDS, PhD
125
Anty Lam, RDH, BSc, MPH
Dental Materials Diametral tensile strength of composite core
material with cured and uncured fiber posts
Sheila Pestana Passos, MDS
Omar El-Mowafy, BDS, PhD
Gildo Coelho Santos Jr., DDS, MSc, PhD
132
Maria Jacinta M.C. Santos, DDS, MSc, PhD
Amin S. Rizkalla, PhD, P. Eng.
Digital Dental Photography Incomplete cusp fractures: Early
diagnosis and communication with patients using fiber-optic
transillumination and intraoral photography
Samer S. Alassaad, DDS
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March/April 2011
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136
Caries Detection and Prevention Utility and effectiveness of
computer-aided diagnosis of dental caries
Kyle D. Tracy, DMD
David C. Gakenheimer, PhD
Stephanie Lacina
Allan G. Farman, BDS, PhD, DSc
145
Trauma in Primary/Young Teeth Management of multiple
trauma avulsion of anterior primary teeth: A three-year followup
Claudia Marina Viegas, MDS
Joao B. Novaes-Junior, PhD
Alexandre Fortes Drummond, PhD
148
Ana Carolina Scarpelli, MDS
Henrique Pretti, MDS
Saul Martins Paiva, PhD
Oral Medicine, Oral Diagnosis Enalapril-induced
angioedema: A dental concern
Kim K. McFarland, DDS, MSHA
e41
Bradley A. Dykstra, DDS
James P. Scheetz, PhD
William C. Scarfe, BDS, MS
Eric Y.K. Fung, PhD
Fixed Prosthodontics Management of the severely worn
dentition with different prosthetic rehabilitation methods: A
case series
Emre Mumcu, DDS, PhD
Hakan Bilhan, DDS, PhD
Onur Geckili, DDS, PhD
Tolga Kayserili, DDS, PhD
e46 Substance Abuse Opiate overdose in an adolescent after a
dental procedure: A case report
James Hawthorne, MD
Madeline Aulisio
Catherine Martin, MD
Coming Next Issue
In the May/June issue
of General Dentistry
• Benefits of additional
courses of systemic
azithromycin in
periodontal therapy
• Alveolar ridge
augmentation—
A case series
• The use of porcelain
repair technique to
improve the plane of
occlusion of an existing
restoration
e50
Dental Materials Gradual surface degradation of restorative
materials by acidic agents
Chanothai Hengtrakool, DDS, MSc, PhD
Ureporn Kedjarune-Leggat, DDS, PhD
In the April issue of
AGD Impact
• Cover story: AGD 2011
Annual Meeting &
Exhibits
• AGD candidate
biographies
82
March/April 2011
General Dentistry
Pamela Stein, DMD, MPH
Laurie Humphries, MD
www.agd.org
Boonlert Kukiattrakoon, DDS, MSc
e63
Luis Rueda, DDS, MSD
Marissa Cooper, DMD
e67
Continuing Dental
Education (CDE) Opportunities
Earn two hours of CDE credit by
signing up for and completing
these exercises based on various
subjects.
Francesca Zicari, DDS
Implants Using cone beam computed tomography to
determine safe regions for implant placement
Sayde Sokhn, BDS, DUA, DUB
Marcel Noujeim, DDS, MS
e78
CREDIT
Fong Wong, DDS, MSD
Andrew Clark, DMD
Endodontics Effect of fiber posts with different emerging
diameter on the fracture strength of restored crownless teeth
Paolo Baldissara, DDS
Luiz Felipe Valandro, DDS, MS, PhD
e72
self CDE
2 HOURS instruction
Complete Dentures Cast metal bases as an economical
alternative for the severely resorbed mandible
Self-Instruction
Exercise No. 279
Infectious Disease Control
123
Self-Instruction
Exercise No. 280
Dentinal Hypersensitivity
& Treatment
129
Self-Instruction
Exercise No. 281
Dental Materials
Ibrahim Nasseh, DCD, DSO, FICD
Oral Diagnosis Recurrence of central odontogenic fibroma: A
rare case
Auremir Rocha Melo, DDS, MSc
Thiago de Santana Santos, DDS, MSc
Marcelo Fernando do Amaral, DDS, MSc
Davi de Paula Albuquerque, DDS
Emanuel Savio de Souza Andrade, DDS, MSc, PhD
Edwaldo Dourado Pereira Jr., DDS, MSc, PhD
e82
108
Dental Materials Flexural bond strength of repaired composite
resin restorations: Influence of surface treatments and aging
Angela Alexandre Meira Dias, DDS, MSD Marcos Oliveira Barceleiro, DDS, MSD, PhD
Rogerio Luiz Oliveira Mussel, DDS, MSS, PhD
Helio Rodrigues Sampaio-Filho, DDS, MSD, PhD
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Instructions for Authors
For an electronic copy of General
Dentistry’s Instructions for
Authors, please visit the journal’s
website at www.agd.org/
publications/GD/AuthorInfo.
General Dentistry
March/April 2011
83
Editor
Roger D. Winland, DDS, MS, MAGD
Associate Editor
Peter G. Sturm, DDS, MAGD
General Dentistry
E-mail: generaldentistry@agd.org
Fax: 312.335.3442
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Norman D. Magnuson, DDS, FAGD, Chair
William E. Chesser, DMD, MAGD
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© Copyright 2011 by the Academy of General Dentistry. All rights reserved.
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March/April 2011
General Dentistry
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Advisory Board
Dental Materials
Oral and Maxillofacial Pathology
Pain Management
Steve Carstensen, DDS, FAGD,
John Svirsky, DDS, MEd, is a board-
is in general practice in Bellevue, Washington.
He is a visiting faculty member of the Pankey
Institute and the Pride Institute and is a
Diplomate of the American Board of Dental
Sleep Medicine.
certified oral and maxillofacial pathologist at
Virginia Commonwealth University in Richmond.
He currently is a professor of oral and
maxillofacial pathology and maintains a private
practice in oral medicine and oral pathology.
Henry A. Gremillion, DDS,
MAGD, is dean of the Louisiana State
Dental Public Health
Oral and Maxillofacial Radiology
Larry Williams, DDS, ABGD,
MAGD, is a Captain in the United States Navy
Kavas Thunthy, BDS, MS, MEd,
Dental Corps, currently stationed at the Great
Lakes Naval Training Center as a member of the
Great Lakes Naval Health Clinic. Dr. Williams
is the Public Health Emergency Officer for the
16 states of the Navy Region MidWest and for
the Naval Health Clinic. He also serves as the
co-chair of the Navy’s Tobacco Cessation Action
Team and as a member of the Department
of Defense Alcohol and Tobacco Advisory
Council. He also teaches for the Dental Hygiene
program at the College of Lake County and as
an assistant clinical professor for the Rosalind
Franklin University for Medicine and Science.
Esthetic Dentistry
Wynn H. Okuda, DMD, is Past National
President (2002–03) and a board-accredited
member of the American Academy of Cosmetic
Dentistry (AACD). He also is on the Advisory
Board of Best Dentists in America and on the
Executive Council of the International Federation
of Esthetic Dentistry (IFED). He practices
cosmetic, implant, and restorative dentistry at the
Dental Day Spa of Hawaii in Honolulu.
Endodontics
Pediatrics
Jane Soxman, DDS, is a Diplomate
has been a professor of oral and maxillofacial
radiology in the Department of Oral Diagnosis,
Medicine, Radiology, at the Louisiana State
University School of Dentistry in New Orleans
since 1975. He was named a Fellow in the
American Academy of Oral and Maxillofacial
Radiology in 1978 and was board-certified by
the American Board of Oral and Maxillofacial
Radiology in 1981.
Oral and Maxillofacial Surgery
Karl Koerner, DDS, FAGD, is a
of the American Board of Pediatric Dentistry,
has authored numerous articles in the dental
literature, and has been recognized as a leader
in continuing education. She maintains a private
practice in Allison Park, Pennsylvania.
Periodontics
Sebastian Ciancio, DDS, is
Distinguished Service Professor and Chair,
Department of Periodontics and Endodontics,
Adjunct Professor of Pharmacology, and Director
of the Center for Dental Studies at the University
at Buffalo, State University of New York.
general dentist in Utah who performs oral
surgery exclusively. He lectures extensively
on oral surgery in general practice and has
made articles, books, and video presentations
available to general practitioners.
Pharmacology
Oral Medicine
Prosthodontics
Daniel E. Myers, DDS, MS, is a
member of the Oral Diagnosis Department,
Dental Associates of Wisconsin, Ltd. in
Wauwatosa.
Sook-Bin Woo, DMD, MMSc,
is assistant professor of Oral Medicine,
Infection and Immunity at Harvard School of
Dental Medicine. She is board-certified in Oral
and Maxillofacial Pathology and Oral Medicine
and practices both specialities in the Boston/
Cambridge area in Massachusetts.
Stephen Cohen, DDS, is one of the
Orthodontics
foremost endodontic clinicians in the country
and lectures worldwide on endodontics.
A board-certified endodontist, Dr. Cohen
specializes exclusively in the diagnosis and
treatment of endodontic infections.
Yosh Jefferson, DMD, FAGD,
Geriatric Dentistry
University School of Dentistry and a professor in
the Department of Orthodontics at LSUSD.
is Past President, International Association
for Orthodontics; a Fellow of the American
Academy of Craniofacial Pain; and a member
of the American Academy of Dental Sleep
Medicine. He maintains a general practice in
Mt. Holly, New Jersey.
Joseph Massad, DDS, is currently the
Director of Removable Prosthodontics at the
Scottsdale Center for Dentistry in Arizona. He
is adjunct faculty at Tufts University School of
Dental Medicine in Boston and the University of
Texas Dental School at San Antonio.
Jack Piermatti, DMD, is a Diplomate
of the American Board of Prosthodontics, the
American Board of Oral Implantology, and the
International Congress of Oral Implantologists.
He is a board-certified prosthodontist in private
practice in Voorhees, New Jersey.
Lea Erickson, DDS, MSPH, is Chief,
Dental Service, at VA Salt Lake City Health
Care System and Clinical Assistant Professor,
University of Utah in Salt Lake City.
Implantology
Wesley Blakeslee, DMD, FAGD,
is a general dentist who practices in New
Jersey. He is a Diplomate of both the American
Board of Oral Implantology/Implant Dentistry
and the International Congress of Oral
Implantologists, and a Fellow of the American
Academy of Implant Dentistry.
P. Emile Rossouw, BSc, BChD,
BChD(Child-Dent), MChD
(Ortho), PhD, is professor and chairman
of the Department of Orthodontics, University
of North Carolina at Chapel Hill School of
Dentistry. He has published and lectured on
clinical orthodontic research nationally and
internationally. He maintains a part-time
clinical practice in addition to his academic
responsibilities.
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March/April 2011
85
editorial
Follow the money
I
want to start this editorial
by reiterating that this is
my opinion and not that
of the Academy of General
Dentistry (AGD), although
I’m sure that some of our
members will agree with
some of my thoughts.
To paraphrase Deep
Throat’s advice during the
Watergate investigation, “If
you want to find the answers
to today’s intrigue, follow the money!” It seems that
everything boils down to money these days, and unfortunately that applies to all areas of health care, including
dentistry. I’m afraid that the government is discovering
that it can’t afford to pay for dental care any more than it
can afford to pay for medical care, and the answer seems
to be to destroy dentistry as a profession and reduce it to
a trade with lower standards of care.
Imagine being a new dentist, eager to begin pursuing
your profession after graduation despite facing at least
$250,000 of debt, only to be told that a sizeable portion
of your job will be supervising staffers who have only two
years of dental training but are allowed to perform the
same procedures you do. Even worse for the profession,
these mid-level providers might be supervised by hygienists or corporate managers or receive no supervision at all.
Some dental educators believe that it is acceptable
to train mid-level providers with money from grants.
Why, then, should I pay dues, give donations, support
endowments, or contribute to any dental school alumni
fund or organization when the school’s purpose has been
reduced to training independent mid-level providers who
will decrease my patient pool, putting me and my future
colleagues out of business?
Even with that said, and contrary to what you may
have heard from some quarters, this issue isn’t about
competition; it’s about being forced to accept and even
support the provision of substandard care, and I for
one can’t do it. I believe that allowing less competent
individuals to deliver surgical and irreversible dental care
borders on criminal. In addition, the implementation of
independent mid-level providers will foist a two-tiered
dental system onto the public, increasing and ensuring
discrimination against the poor and uninsured.
Some dentists feel that lowering our standards of
care to treat more patients is better than providing the
best dental care in the world. This view is refuted by no
less an authority than the National Dental Association
(NDA). The NDA believes that all citizens are entitled
to equal protection and health care under the law. The
NDA also believes that a two-tiered system which
operates under the premise that “something is better
than nothing” is unacceptable. The NDA considers
it critical that the highest quality and standards of
care are always maintained in meeting the needs of
the underserved community. All of these positions are
supported by the AGD.
I have written before that the love of money is the
root of all evil, and now that statement has a corollary:
“The lack of money is the root of all medical and dental
evil.” Government officials seem to think that our objection to the independent mid-level provider position is
simply the whining of a bunch of rich dentists. They
don’t recognize that dentists have for years accepted—at
a loss—below-market-value payments in order to prop
up a continually underfunded welfare system, while still
providing the highest level of dental care possible.
There is more to success than making money, and
one way for us to succeed is to preserve our current
high standards of care. I encourage you to read the
AGD White Paper, titled “Increasing Access to and
Utilization of Oral Health Care Services” (available at
www.agd.org/files/webuser/website/advocacy/accesstocare
whitepaper.pdf ), to get the facts about this issue and
to contact the AGD Advocacy department to find out
how you can get involved. We need to show those who
would destroy our noble profession that we will not go
down silently or without a fight.
Roger D. Winland, DDS, MS, MAGD
Editor
COMMENT
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March/April 2011
General Dentistry
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Pharmacology
Botulinum toxin (Botox, Dysport,
and Myobloc): Pharmacology 101
Richard L. Wynn, PhD
B
otox is the brand name of Allergan’s purified
protein-botulinum toxin type A, derived from
anaerobic bacterium Clostridium botulinum. Type
A is one of seven distinct botulinum toxins (identified
as types A–G) produced by different strains of the
Clostridia bacterium. Each botulinum type produces a
different immunologic response and is made by a different manufacturing process. Botulinum toxin exists
as three commercial products on the U.S. market:
onabotulinumtoxinA (Botox, Botox Cosmetic), abobotulinumtoxinA (Dysport, Medicis Aesthetics Inc.), and
rimabotulinumtoxinB (Myobloc, Solstice Neurosciences,
LLC). As of this writing, no other antigenic toxins are
available for therapeutic use.
Botulinum toxin has been assessed as being the most
poisonous substance known to man.1 One gram of a
crystalline form of the toxin, if milled into proper size
for inhalation and dispersed evenly, would kill more
than 1 million people. Technically, however, it has been
impossible to crystallize that much of the toxin for such
dissemination. Food-borne botulinum toxin would kill
far fewer people but could be used as a terrorist attack.
Unlabeled/investigational uses include treatment of
oromandibular dystonia, spasmodic dysphonia (laryngeal
dystonia), and other dystonias (for example, writer’s
cramp, focal task-specific dystonias); migraine treatment
and prophylaxis; and treatment of dynamic muscle contracture in pediatric patients with cerebral palsy.2
AbobotulinumtoxinA (Dysport)
Approved uses include treatment of cervical dystonia
in both toxin-naive and previously treated patients;
temporary improvement in the appearance of moderate
to severe glabellar lines associated with procerus, and
treatment of corrugator muscle activity.3
No unlabeled/investigational uses have been suggested
for Dysport.
RimabotulinumtoxinB (Myobloc)
Approved uses include treatment of cervical dystonia.4
Unlabeled/investigational uses include treatment of
cervical dystonia in patients who have developed resistance to Botox, Botox Cosmetic, or Dysport.4
More on Botox
Approved and unlabeled uses
The U.S. FDA-approved uses and unlabeled/investigational uses for botulinum toxin are listed below.
OnabotulinumtoxinA (Botox; Botox Cosmetic)
Approved uses include treatment of strabismus and
blepharospasm associated with dystonia (including
benign essential blepharospasm or VII nerve disorders)
in patients at least 12 years of age; treatment of cervical
dystonia (spasmodic torticollis) in patients at least 16
years of age; temporary improvement in the appearance
of lines/wrinkles of the face (moderate to severe glabellar lines associated with corrugator and/or procerus
muscle activity) in adult patients up to age 65; treatment of severe primary axillary hyperhidrosis in adults
not adequately controlled with topical treatments; and
treatment of focal spasticity (specifically upper limb
spasticity) in adults.2
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Botox has been approved in more than 75 countries to
treat 20 different neurological disorders. In addition to
its cosmetic application, Botox has been used in the U.S.
for nearly 15 years for a range of therapeutic applications, including treatment of crossed eyes and excessive
sweating.1 Botox ranked as the number one minimally
invasive cosmetic procedure in the U.S. in 2005.
Botulinum toxin was developed in the 1940s by the
U.S. and other countries as a biological weapon. At
much lower doses, it can temporarily alleviate neurological disorders, and in this capacity it was the first biological toxin licensed for the treatment of human diseases.
The toxin acts by preventing the release of the neurotransmitter acetylcholine from vesicles at the neuromuscular junction. Chemically, the toxin is known as a
proteinase and is able to cleave one or more of the fusion
proteins by which the neuronal vesicles release acetylcholine. In the absence of acetylcholine, muscle contraction
or gland activity is temporarily shut down. When used
to treat medical disorders, minute amounts of the toxin
are injected directly into the targeted muscle or gland.
The shutdown of muscle or glandular activity lasts from
one to six months, depending on the medical indication. Eventually, the nerve endings recover and revert to
normal acetylcholine release. To maintain the therapeutic
effect, another injection may be needed.
In addition to its cosmetic uses, Botox has been indicated by the FDA for the treatment of serious medical disorders; the first of these was in 1989 for uncontrolled eye
blinking (blepharospasm) and treatment of crossed eyes
(strabismus). In 2000, Botox gained FDA approval for
cervical dystonia, defined as involuntary neck and muscle
spasms that can cause abnormal postures of the head. In
2002, Botox gained FDA approval for cosmetic use that
included treatment to improve the appearance of lines/
wrinkles of the face (moderate to severe glabellar lines
associated with corrugator and/or procerus muscle activity). Finally, in 2004, the FDA approved the use of Botox
as a treatment for excessive underarm sweating (hyperhidrosis) that cannot be managed with topical agents.
Outside the U.S., Botox is approved for the treatment of juvenile cerebral palsy and adult spasticity. In
the U.S., it is used for off-label indications including
migraine headache, chronic lower back pain, stroke,
traumatic brain injury, and cerebral palsy.
History
An outbreak of botulism among people who had eaten
uncooked blood sausage in southern Germany in 1815
led a physician named Kerner to publish a precise
description of botulism symptoms, from blurred vision
to progressive muscle weakness and culminating in
respiratory failure.1 He postulated that minute quantities
of this disease-producing substance might be able to
treat disorders of the central nervous system. In 1897, a
Belgian professor of bacteriology named van Ermengem
discovered the bacterium responsible for producing the
toxin and renamed the disease from Kerner’s disease to
botulism, from the Latin botulus (sausage).
Botulinum toxin was isolated from the Clostridium
botulinum organism in the early 1920s. Later that
decade, scientists at the University of California, San
Francisco, first isolated botulinum toxin type A, while
scientists at the University of Wisconsin purified the
botulinum type A toxin in crystalline form in 1946.
Botox warning
Complete information on Botox, including administration, dosing, and adverse effects, is available both in
print and online.2 Meanwhile a serious black-box warning label has been issued for Botox by the FDA. This
warning reads as follows:
Distant spread of botulinum toxin beyond the site of
injection has been reported; dysphagia and breathing difficulties have occurred and may be life threatening; other
symptoms reported include blurred vision, diplopia, dysarthria, dysphonia, generalized muscle weakness, ptosis,
and urinary incontinence which may develop within
hours or weeks following injection. Risk likely greatest
in children treated for the unapproved use of spasticity.
Systemic effects have occurred following approved and
unapproved uses, including low doses. Immediate medical attention required if respiratory, speech, or swallowing difficulties appear.5
Specific reports on adverse events associated
with use of botulinum toxin
Ihde and Konstantinovic reviewed three trials that
used botulinum toxin type B to treat cervical dystonia
and one trial that used botulinum toxin type A to
treat chronic facial pain.6 From the cervical dystonia
studies, the adverse drug reactions (ADRs) were mild
and transient, with numbers needed to harm ranging
from 12–17. (Numbers needed to harm represents the
number of patients treated before observing an adverse
event.) Dystonia, injection site reactions, and general
reactions such as flu-like symptoms, nausea, and headache were some of the events reported. Dry mouth was
reported in 3–33% of patients, while dysphagia ranged
from 0–27% of patients.
From the chronic facial pain study, using botulinum
toxin type A, the rate of ADRs was less than 1%. The
ADRs were relatively mild and transient and included
dry mouth, bruising at the injection site, and itching at
the injection site. Dysphagia and temporary paralysis of
the muscles affecting expression occurred in one patient
(N = 90).
Cote et al reviewed all of the serious ADRs reported
to the FDA since botulinum toxin type A was licensed
and the nonserious ADRs reported from December
2001 to November 2002 following botulinum toxin
type A administration.7 There were a total of 1,437 ADR
reports, with 406 occurring with therapeutic uses and
1,031 occurring with cosmetic uses. Therapeutic uses
included treatment of severe primary axillary hyperhidrosis and treatment of strabismus and blepharospasm
associated with dystonia, cervical dystonia, and focal
spasticity. Cosmetic uses included temporary improvement in the appearance of lines/wrinkles in the face
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General Dentistry
March/April 2011
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(moderate to severe glabellar lines associated with corrugators and/or procerus muscle activity).
Of the 406 reports of ADRs after therapeutic uses,
217 met the FDA definition of serious while 189 were
nonserious. The serious ADRs included 28 deaths and
17 seizures. The deaths were attributed to heart attacks,
cerebrovascular accidents, pulmonary emboli, pneumonia, or unknown causes. Most of the serious ADRs
corresponded to the risks described in FDA-approved
labeling, such as dysphagia, muscle weakness, allergic
reactions, flu-like syndromes, and injection site trauma.
Of the 1,031 ADRs after cosmetic uses, 36 were of a
serious nature and 995 were nonserious. No deaths were
reported in this group. The serious ADRs included focal
facial paralysis, muscle weakness, dysphagia, flu-like
symptoms, and allergic reactions. The most commonly
noted nonserious ADRs included lack of affect (63%),
injection site reaction (19%), and ptosis (11%.)
In a published commentary, Batra et al observed that
of the ADRs reported in the study by Cote et al after
therapeutic use of botulinum toxin type A, 47% were
classified as serious, compared to 3.5% of serious ADRs
reported after cosmetic uses.7,8 In addition, the proportion of serious ADRs from December 2001 through
November 2002 was 33-fold higher for patients given
botulinum toxin type A for therapeutic uses than for
those receiving it for cosmetic uses (19.5% vs 0.6%).
In contrast to the Cote et al study that reviewed
only those ADRs reported to the FDA, Naumann and
Jankovic reviewed the ADRs described and reported
in randomized controlled trials of botulinum toxin
type A.7,9 They reviewed 36 studies involving 2,309
subjects through searches of online databases, including
MEDLINE, for the years 1966–2003. Of the 2,309
subjects, 1,425 received botulinum toxin type A treatment. No study reported any severe adverse events. The
reporting of any mild to moderate adverse event showed
a rate of approximately 25% in the groups treated with
botulinum toxin type A, compared to 15% in control
groups. Focal weakness was the only adverse event that
occurred significantly more often with botulinum toxin
type A than in the control. Some of the mild to moderate ADRs reported in both treatment groups and control
groups included injection site reactions, headache, ptosis,
and neck pain. The authors concluded that the results
of their meta-analysis and experience from long-term,
open-label investigations demonstrated that botulinum
toxin type A has a favorable safety and tolerability profile
across a broad spectrum of therapeutic uses.9
Author information
Dr. Wynn is a professor of pharmacology, Department
of Oral Craniofacial Biological Sciences, Dental School,
University of Maryland at Baltimore.
References
1. Ember L. Botox. Chem Engineer News 2005;83(25):3. Available online at:
http://pubs.acs.org/cen/coverstory/83/8325/8325botox.html.
2. Wynn RL, Meiller TF, Crossley HL, eds. Drug information handbook for dentistry, ed. 16. Hudson, OH: LexiComp;2010:1261-1262.
3. Wynn RL, Meiller TF, Crossley HL, eds. Drug information handbook for dentistry, ed. 16. Hudson, OH: LexiComp;2010:27.
4. Wynn RL, Meiller TF, Crossley HL, eds. Drug information handbook for dentistry, ed. 16. Hudson, OH: LexiComp;2010:1492.
5. U.S. Food and Drug Administration. FDA’s medwatch safety alerts: June 2009.
Available online at: http://www.fda.gov/forconsumers/consumerupdates/ucm
164442.htm. Accessed November 30, 2010.
6. Ihde SK, Konstantinovic VS. The therapeutic use of botulinum toxin in cervical
and maxillofacial conditions: An evidence-based review. Oral Surg Oral Med
Oral Pathol Oral Radio Endod 2007;104(2):e1-e11.
7. Cote TR, Mohan AK, Polder JA, Walton MK, Braun MM. Botulinum toxin type A
injections: Adverse events reported to the US Food and Drug Adminstration in
therapeutic and cosmetic cases. J Am Acad Dermatol 2005;53(3):407-415.
8. Batra RS, Dover JS, Arndt KA. Adverse event reporting for botulinum toxin type
A. J Am Acad Dermatol 2005;53(6):1080-1082.
9. Naumann M, Jankovic J. Safety of botulinum toxin type A: A systematic review
and meta-analysis. Curr Med Res Opin 2004;20(7):981-990.
Manufacturers
Allergan, Irvine, CA
800.347.4500, www.allergan.com
Medicis Aesthetics Inc., Scottsdale, AZ
866.222.1480, www.dysportusa.com
Solstice Neurosciences, LLC, Louisville, KY
888.900.8796, www.myobloc.com
COMMENT
90
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General Dentistry
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Restorative Dentistry
Pre-prosthetic orthodontics for esthetics
and function in restorative dentistry
Bruce W. Small, DMD, MAGD
P
redictable restorative dentistry can be challenging
for many reasons. Difficult clinical procedures,
restorative choices, periodontal problems, occlusion, and laboratory work are just a few of the problems
that get in the way of long-lasting dentistry. Tooth
position prior to restorative work is another factor that
can be changed if necessary, making a case a little easier.
Also, changing the position of teeth can improve function and esthetics for the patient.
This column presents cases of orthodontic movement
of teeth for both pre-prosthetic and esthetic reasons.
The cases were completed with traditional orthodontic
therapy or successive clear polymer aligners.
Case report No. 1
A 55-year-old woman was referred to the office from
an oral surgeon. She originally was referred to the
surgeon by her previous dentist for extraction of both
maxillary central incisors (Fig. 1–3) and placement of a
six-unit bridge. She had two ill-fitting crowns with posts
attached, which had come loose several times. The oral
surgeon (who had practiced as a general dentist for six
years) and the patient discussed the possibility of saving
the teeth.
Fig. 1. Occlusal view of the old crowns on
central incisors with faulty margins.
The patient was informed that several therapeutic
options options were available:
• Extraction of both central incisors and placement of
a six-unit bridge, which could cause an unnaturallooking pontic space at the gingival level.
• Extraction of the central incisors and placement of two
implants, which probably would leave an open gingival
embrasure.
• Attempting to restore the mouth with new posts and
cores. However, part of the preparations would be
below the gingival margin, and creating a ferrule would
be difficult, if not impossible. Hygiene also could be a
problem.
• Placement of new posts and cores, followed by orthodontic extrusion and periodontal surgery.
The patient chose the fourth option, which had
been suggested as the ideal treatment for this case. In
consultation with the orthodontist, only 3.0 or 4.0 mm
of movement would be necessary to create a proper
crown:root ratio.
New posts were placed and three TMS pins (Coltene/
Whaledent, Inc.) were added to each tooth for additional
retention to the composite cores. Two pins were placed
in the occlusal portion (Fig. 4 and 5) and one was placed
Fig. 2. Preoperative occlusal view of the
incisors without posts and crowns.
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Fig. 3. Preoperative radiograph of the old
crowns.
General Dentistry
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91
Fig. 4. Radiograph of new posts, TMS pins, and
composite buildups.
Fig. 5. Lingual occlusal view of provisional crowns with TMS pins on the lingual aspect.
Fig. 6. Mandibular occlusal view of a 13-year-old girl with anodontia.
Fig. 7. Maxillary view of the patient in Fig. 6 with orthodontic appliances
prior to implant placement.
esthetic environment that can be easily maintained by
the patient, prior to final placement of the crowns for
teeth No. 6–11.
Case report No. 2
Fig. 8. Retracted anterior view of the patient in Fig. 6.
through the lingual portion of the provisional crowns to
help prevent dislodgement during orthodontics. As the
teeth move, occlusal adjustments will be made to create
room for the movement.
Following completion of the orthodontics, a periodontist will restore the biologic width and create an ideal
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A 13-year-old girl was referred to the office for a consultation regarding implants. She had anodontia with
many teeth congenitally missing. Orthodontics was
completed, making room for implant placement as ideal
as possible (Fig. 6–9).
One compromise was made: Site No. 12 was unavailable for implant placement, so tooth No. 11 was used
as an abutment for a three-unit bridge with the implant
in site No. 13 (Fig. 10). Chee and Mordohai have recommended not connecting natural teeth to implants,
but there was no viable alternative in this case.1 The
patient and parents were informed of possible intrusion
of the canine and a bridge was created. The case was
completed and the patient was very happy to have a
Fig. 9. Anterior view of the patient in Fig. 6, with implant abutments and metal copings
at try-in.
Fig. 11. Maxillary occlusal view of the completed case.
Fig. 14. Preoperative radiograph
of an endodontic lesion in the
anterior mandible.
Fig. 10. Maxillary view of the maxillary left side, showing
implant abutments and virgin tooth No. 11.
Fig. 12. Mandibular occlusal view of the completed case.
Fig. 15. Preoperative clinical view of misaligned mandibular incisors.
full complement of teeth for the first time in her life at
age 17 (Fig. 11–13).
Case report No. 3
A 62-year-old man complained of pain and swelling in the
anterior mandible (Fig. 14). Tooth No. 24 was chipped
and in traumatic occlusion (Fig. 15). It was suggested that
endodontic therapy be performed and that clear plastic
Fig. 13. Facial view of the
completed case.
Fig. 16. Postoperative radiograph
of completed endodontics and
the healed periapical area.
aligners be used to move the tooth into a better occlusal
relationship. The patient accepted the treatment plan and
the endodontist treated the case successfully (Fig. 16).
After five months of movement using successive computergenerated aligners, the tooth was brought into a more ideal
position (Fig. 17). After the completion of orthodontics,
four all-ceramic crowns were constructed, seated, and
bonded using a self-etching resin cement (Fig. 18–20).
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General Dentistry
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93
Fig. 17. Aligner in place with composite buttons on teeth.
Fig. 18. Postoperative view of completed orthodontics.
Fig. 19. Die model illustrating preparations for all-ceramic crowns.
Fig. 20. Anterior view of the completed case.
Discussion
Author information
The three cases presented here demonstrate the use
of orthodontics for prosthetic reasons. Oftentimes,
restorative treatment can be simplified and made easier
for both dentist and patient by moving the teeth into
more ideal positions, sometimes minimizing the need for
additional prosthetics.
Tooth movement can be accomplished via traditional
brackets and wires or the newer aligner therapy, with
excellent results obtained from both methods. It is
important to know the limits of both treatment modalities and to be able to address any problems that occur
during treatment. It is highly recommended that general
dentists be properly trained in diagnosis and treatment
using aligner therapy before attempting this new method
of orthodontics. A close association with a boardcertified orthodontist is always an advantage.
Dr. Small is in private practice in Lawrenceville, New
Jersey, and is an adjunct professor at the University of
Medicine and Dentistry of New Jersey. He is a visiting
faculty member of the L.D. Pankey Institute in Key
Biscayne, Florida, where he also serves on the Board of
Advisors.
References
1. Chee WW, Mordohai N. Tooth-to-implant connection: A systematic review of
the literature and a case report utilizing a new connection design. Clin Implant
Relat Res 2010:12(2)122-133.
Manufacturers
Coltene/Whaledent, Inc., Cuyahoga Falls, OH
800.221.3046, www.coltene.com
COMMENT
94
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General Dentistry
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Dental Materials
Latest innovations in flowable composites
Michael B. Miller, DDS
P
hotocured flowable composites were introduced
to the dental profession in 1995 with Revolution
(Kerr Corporation). The original manufacturer (E
& D Dental Products) recommended that the product
could be used for Class III, IV, and V restorations,
porcelain veneer cementation, porcelain and marginal
defect repairs, sealants, and core buildups. Surprisingly,
one of the most popular contemporary uses of flowable
composites—the first increment at the bottom of the
proximal box for a Class II preparation—was not even
mentioned initially as a use for Revolution.
While Revolution was (and still is) essentially a modified resin cement, new flowables have branched into
three new directions: low-stress, self-adhesive, and high
strength/low wear.
Low-stress
Conventional flowable composites have comparatively
higher shrinkage than sculptable composites, likely
due to the lower filler load and higher resin percentage
of flowables. Because it is the resin that shrinks, it is
quite logical to assume that flowables will shrink more,
causing increased stresses on the developing bond;
however, the resin in the new low-stress flowables
presumably has been modified to minimize this
stress despite the material still shrinking more than
sculptable composites.
The big advantage with low-stress flowables is that they
can be placed in relatively thick layers (about 4.0 mm),
which can speed up the procedure, a goal that most
dental practitioners want anyway. But shrinkage stress is
only one part of the equation: If you place any composite in thicknesses greater than 2.0 mm, the ability to cure
it thoroughly comes into question.
So what do we really know about these products? The
REALITY Research Lab (RRL) has studied the depth
of cure of two recently introduced products, Venus Bulk
Fill (Heraeus Dental North America) and SureFil SDR
flow (Dentsply Caulk). This was done by comparing the
surface hardness to that at the bottom of the proximal
box, even if the thickness was 4.0 mm. The results
showed that both products can exceed the 80% cure
goal; however, to achieve this goal, the materials must
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be cured for 40 seconds, not the 20 seconds recommended by the respective manufacturers.
But what about the claim of lower curing stress? The
RRL found that both Venus Bulk Fill and SureFil SDR
flow had significantly less shrinkage stress compared to
a conventional flowable (Filtek Supreme Plus Flowable,
3M ESPE). Further, this shrinkage stress was statistically
the same as that of a glass ionomer base (Fuji IX GP
Extra, GC America Inc.).
The unanswered question, of course, is what does this
lower shrinkage stress mean when it comes to tooth
integrity and restoration stability over time? A laboratory
study cannot provide that answer, but at least some peace
of mind comes from not putting undue stresses on a
tooth, because glass ionomers like Fuji IX have been used
successfully for many years.
Nevertheless, if you fill a proximal box with 4.0 mm of
flowable composite, there is a good likelihood that this
flowable increment will be sufficiently occlusal to form all
or part of the contact area. However, the question remains
as to whether any flowable, low-stress or not, resists wear
well enough to use in restoring contacts. Therefore, I still
believe that it would be prudent to continue restoring
contacts with a more heavily filled, sculptable composite.
Self-adhesive
Cements were the first resin-based materials to bear the
self-adhesive label, and because cements and flowables
can be used interchangeably in many respects, it is not
suprising that flowables were next. Similar to what happened with low-stress flowables, two products, Vertise
Flow (Kerr Corporation) and Fusio (Pentron Clinical),
kick-started the self-adhesive trend.
From a clinical standpoint, a self-adhesive flowable has
great appeal, since it eliminates the need for a bonding
agent. However, even though the application procedure
is not difficult, it is quite specific, meaning that you
cannot simply syringe these materials into preparations,
as you would with a conventional flowable.
With Vertise Flow, for example, the first increment
is injected in a thin layer (less than 0.5 mm) after the
tooth has been cleaned and dried. This thin layer is
necessary because it acts, in effect, as a self-etching
adhesive. Next, this layer is agitated aggressively, using
High strength/low wear
the disposable brushes that come with the kit. Once this
Setting aside the comments above about low-stress flowfirst increment has been placed, you can add another
ables having questionable wear resistance for restoring
layer to finish restoring a small Class I restoration or
contact areas, the latest trend for flowables is the claim
switch to a more conventional composite in the case of a
that some of them are actually strong enough and wearlarger preparation.
resistant enough to be used for the entire restoration,
To complicate matters, the technique for Fusio has
regardless of classification. This means that these speimportant differences from that for Vertise Flow. The
cialized flowables presumably could be used to restore
preparation is not dried after cleaning, because Fusio
even Class II and IV lesions and/or fractures. Indeed,
bonds better to a glistening wet tooth surface. Also,
GC America Inc. describes its G-aenial Universal Flo as
a rubbing technique for the
the first injectable flowable that
initial layer is used instead
“performs like a restorative.”1
of the agitation method for
GC America Inc. is not alone
The jury is still out on
Vertise Flow. These technique
in claiming that its flowable is
variances point out that the
as strong and wear-resistant as
the bond stability of
application protocols for these
sculptable, more heavily filled
products are material-specific,
composites. VOCO America
self-adhesive flowables.
which means that there is a
promotes Grandio Flow as the
learning curve if you switch
“first flowable composite that is
from one product to the other.
strong as universal composites,”
Another difference between these products is their
while Shofu Dental Corporation describes the flexural and
indications for use. Fusio is described as being “liquid
compressive strength of Beautifil Flow Plus as being “an
dentin,” which would seem to imply that it should be
injectable hybrid restorative material for all indications.”2,3
used only as a base or liner, but instead it is recomIs this a positive trend? Well, on the surface, this is
mended for definitive small Class I, III, and V restoraan attractive option, because squirting a flowable into
tions. Meanwhile, Kerr Corporation is taking a more
a cavity preparation is a fairly easy task compared to
conservative stance with Vertise Flow by restricting its
packing a thicker composite, especially in areas such as
indications (at this time) to small Class I restorations,
a proximal box. However, as noted earlier with the lowpit and fissure sealants, and liners/bases under larger
stress flowables, depth of cure can rear its ugly head, as
restorations. In other words, using it for other types of
evidenced by the manufacturer’s recommendation that
definitive restorations such as Class V or core buildups is
G-aenial Universal Flo be layered in increments of only
not yet recommended.
1.0–1.5 mm, depending on the shade. These are wise
So is it possible to achieve as strong a level of adhesion
instructions, verified by tests in the RRL, although the
to tooth structure with these new products as you would
same tests indicate that the manufacturer-recommended
by using a bonding agent in combination with a more
10-second curing time with a high-powered LED curing
conventional flowable? The simple answer is no, accordlight is not sufficient. If you use this product, I strongly
ing to tests performed in the RRL, where the bond
recommend that you cure each increment for at least 20
strengths, especially immediately after photocuring, were
seconds, or even 40 seconds for the first increment deep
substantially lower for the self-adhesive products. It is
in the proximal box.
worth noting, though, that with Vertise Flow in parIf the depth of cure conundrum can be resolved, can
ticular, bond strengths to feldspathic porcelain, zirconia
you feel confident that one of these “strong” flowables
(Lava), and three different types of metal were quite
will be adequate for the complete restoration of virtuhigh, especially after 24 hours.
ally any lesion? My gut feeling at this point is no. These
However, simple answers may not always be correct.
products probably will perform adequately in primary
For example, RRL bond strength tests of self-adhesive
teeth and minimally invasive preparations, but I would
resin cements also produced significantly lower results
caution against using them as the sole restorative matecompared to a more conventional bonding agent/cement
rial in moderate to large Class I and II restorations.
combination. On the other hand, anecdotal reports show
that these cements do not appear to be suffering mass
The bottom line
debondings. The jury is still out on the bond stability of
Flowable composites used to be merely low viscosity
self-adhesive flowables.
versions of their sculptable brethren, but this legacy
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General Dentistry
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97
is changing fast. This column is intended to provide
an overview of the new flowables before you jump in
head-first.
3. Product brochure. Available at: http://shofu.com/BeautifilFlowPlusBrochure.pdf.
Accessed December 2, 2010.
Manufacturers
Disclaimer
The author has evaluated all of the products mentioned
in this article but has no financial interest in them or
their manufacturers.
Author information
Dr. Miller is the president of REALITY Publishing
Company and editor-in-chief of its publications. He also
maintains a general practice in Houston, Texas.
References
1. GC America Inc. website. Available at: http://www.gcamerica.com/products/
operatory/G-aenialFlowable/. Accessed December 2, 2010.
2. VOCO America website. Available at: http://www.vocoamerica.com/
praeparate/us/html/prodinfo/grandio_flow.htm. Accessed December 2, 2010.
Dentsply Caulk, Milford, DE
800.532.2855, www.surefilsdrflow.com/
GC America Inc., Alsip, IL
800.323.7063, www.gcamerica.com
Heraeus Dental North America, South Bend, IN
800.431.1785, www.heraeus-dental-us.com
Kerr Corporation, Orange, CA
800.537.7123, www.kerrdental.com
Pentron Clinical, Wallingford, CT
800.551.0283, www.pentron.com
Shofu Dental Corporation, San Marcos, CA
800.827.4638, www.shofu.com
VOCO America, Briarcliff Manor, NY
888.658.2584, www.vocoamerica.com
3M ESPE, St. Paul, MN
888.364.3577, www.3mespe.com
COMMENT
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Infectious Disease Control
CDE
2 HOURS
CREDIT
Evaluation of the microbial flora found
in woodwind and brass instruments and
their potential to transmit diseases
R. Thomas Glass, DDS, PhD
n
Robert S. Conrad, PhD
n
Gerwald A. Kohler, PhD
Previous studies of dental devices (toothbrushes, dentures, and
protective athletic mouthguards) have demonstrated microbial
contamination of these devices and possible transmission of infectious diseases to the users. Since woodwind and brass instruments
come into intimate contact with the musician’s oral cavity and
often are passed from student to student without sanitization, the
question arises as to whether these instruments are contaminated
and can transmit microbial diseases. The purpose of this study was
to determine if woodwind and brass instruments and/or their cases
harbor opportunistic, pathogenic, or allergenic microorganisms that
can be transmitted to the musician.
The internal components of woodwind and brass instruments
M
any children and young
people participate in school
and extracurricular band
ensembles. Woodwind and brass
instruments comprise a substantial
portion of these ensembles. Often,
instruments used by students are on
loan from the school and previously
have been played by individuals
whose health histories are unknown
to the recipients. Also, private
organizations, such as the Mr. Holland’s Opus Foundation, distribute
donated used instruments to underprivileged inner-city children.1 Used
woodwind and brass instruments
have not been evaluated thoroughly
as a suitable habitat for microbial
growth. However, the mouthpieces,
internal tubing, intricate valves,
keys, pads, hinges, and cases could
provide potential sites for microbial
contamination, facilitating the transmission of microbial diseases.
When various parts of woodwind
and brass instruments are used,
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March/April 2011
James W. Bullard, MS
harbored opportunistic, pathogenic, and/or allergenic microorganisms. The highest concentrations of microorganisms were found
consistently at the mouthpiece end, but there was evidence of
contamination throughout the instruments and their cases. The
close proximity of contaminated mouthpieces to the oral cavity
could facilitate local and systemic dissemination of the resident
opportunistic, pathogenic, and/or allergenic microorganisms.
General dentists should determine whether patients play a brass or
woodwind instrument and be aware of the possible impact of this
activity on the oral cavity and the entire body.
Received: July 13, 2010
Accepted: September 7, 2010
they become repositories for the
users’ oral and pulmonary secretions.2 Because these instruments
come into intimate contact with
the musicians’ oral and respiratory
mucous membranes, such exposures
may facilitate microbial transmission. Furthermore, as these instruments are repeatedly played, they
build up visible amounts of organic
material, providing an excellent
habitat for microbial growth.
Even though the instruments may
lie dormant during the summer
months between school sessions,
they could remain contaminated.
Methods for clearing such organic
accumulations from woodwind
and brass instruments include
repeatedly aspirating the secretions
from the instrument; evacuating
materials from water valves (spittraps); wiping areas with fingers
and cleaning cloths; and flushing
the instruments with antimicrobial
solutions. These routine procedures
General Dentistry
n
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could provide further opportunities for disease transmission by
contaminating the musicians’ hands,
which in turn could contaminate
other instruments or the musicians’
eyes, nose, or mouth. In addition
to direct contact, microorganisms
could be expelled into the local
enclosed environment (the band
room) by playing the instruments.
There has been a great deal of
research recently into the transmission of microorganisms, including
bacteria, fungi, and viruses by oral
means. However, little is known
regarding the specific health hazards
associated with the sharing of contaminated wind instruments. Despite
studies confirming a relationship
between breathing difficulties and
playing wind instruments, no association has been made with the effects
of instrument contamination.3,4
While minimal research has
been conducted specifically on
microorganisms harbored in wind
Chart 1. A flow chart outlining the experimental design of this study.
De-identified
previously
played wind
instruments
received from
a local high
school band
(seven brass and
six woodwind
instruments)
Previously played woodwind instrument
mouthpieces and internal chambers cultured for
one minute per site using moist sterile swabs
• Reedcomponentssectionedandtouched
directly to BAP and Sab;
• SwabsstreakedonBAPandSab;
• Swabsplacedin10mLsterilewaterand
vortexed for two minutes. Serial dilutions
made from 10 -3 to 10 -8. Plated on BAP in
triplicate for CFUs/swab.
Previously played brass instrument mouthpieces,
tubing, and spit valves cultured for one minute
per site using moist sterile swabs
• SwabsstreakedonBAPandSab;
• Swabsplacedin10mLsterilewaterand
vortexed for two minutes. Serial dilutions
made from 10 -3 to 10 -8. Plated on BAP in
triplicate for CFUs/swab.
instruments, there is an extensive
body of research regarding the
presence of opportunistic and
pathogenic microorganisms on and
within oral devices. Multiple studies
conducted by Glass et al found that
toothbrushes harbor pathogenic
microorganisms involved in oral,
pulmonary, and systemic diseases.5-13
These researchers also noted that
patients who are immunocompromised were at far greater risk than
healthy individuals of developing
microbial diseases through contaminated toothbrushes.9,12
Additional research on other oral
devices such as dentures and protective athletic mouthguards found
colonization by similar potential
disease-producing microorganisms.14-23 In the most recent study of
53 protective athletic mouthguards,
Glass found that the most common
of the 253 Gram-positive isolates
were Staphylococcus spp. (182)
and Micrococcus spp. (54).24 The
remaining 17 isolates were various
Streptococcus spp. In the same
study, 14 of the Staphylococcus isolates were S. aureus, two of which
were methicillin-resistant (MRSA).
Of the non-aureus Staphylococcus
spp., 53% were methicillin-resistant, while 76% of the Micrococcus
spp. were methicillin-resistant.
Even more disconcerting was the
finding that 71% of the non-aureus
Staphylococcus and Micrococcus
spp. were resistant to triclosan, a
common antimicrobial agent used
in some instrument rinses. This
finding of resistance factors in
non-aureus Staphylococcus spp. has
important clinical implications for
the prevention and treatment of
infections in humans.
A 2009 study of 1,391 hospitalized patients found that 188
(13.5%) had antimicrobial-resistant
infections (ARI), resulting in
medical costs ranging from
$18,588–$29,069 per patient.25
www.agd.org
All BAP incubated at 37°C and
read at 48 hours.
All Sab initially incubated at 37°C
and read at 48 hours.
Sab then incubated at 22°C
and read at 120 and 168 hours;
streaked colony intensity
evaluated by three investigators
at 48 hours using Table 1.
CFUs/swab evaluated by three
investigators at 48 hours;
representative microorganisms
identified using standard
laboratory methods.
The additional societal costs in
this cohort were estimated to be
$10.7–$15.0 million. Based on this
study and several others, it is suggested that such avoidable infections
resulted in more than $35 billion in
societal cost annually and more than
8 million additional days spent in
the hospital nationwide.26
The hypothesis of this study was
that the internal components and/
or the cases of woodwind and brass
instruments harbor potentially
pathogenic, opportunistic, or
allergenic microorganisms that can
be isolated and identified by routine
laboratory methods.
Materials and methods
In order to answer the hypothesis,
the protocol was followed as outlined in Chart 1. A local small-town
high school band agreed to participate in the proposed study. For this
institutional review board (IRB)approved study, 13 de-identified
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Infectious Disease Control Evaluation of the microbial flora found in woodwind and brass instruments
Table 1. Colony intensity scale.
Value
Colonies/cm2
0
≤5
1
6–25
2
26–100
3
>100, but without confluent
growth
4
too numerous to count, with
confluent growth
previously played wind instruments
(seven brass and six woodwinds)
were utilized. Although the instruments were de-identified, a history
was obtained regarding the length of
time between when the instrument
was last played and the testing. Six
of these instruments (three brass
and three woodwinds) had been
played within a week of testing,
while the other seven instruments
(four brass and three woodwinds)
had not been played for at least one
month prior to the study.
Before the microbial flora were
sampled, appropriate photographs
were made of the interstices and
cases of the instruments. A total of
117 different sites, including the
mouthpieces, internal chambers,
and cases of the study instruments,
were cultured by swabbing each area
with a moist sterile swab for one
minute. All swabs were immediately
streaked onto a blood agar plate
(BAP) and a Sabouraud dextrose
plate (Sab). The reeds were touched
directly onto the media, both intact
and after cross-sectioning. The
swabs or reeds were then placed in
10 mL of sterile water and vortexed
for two minutes. Serial dilutions
of the test waters were made from
10-3 to 10-8 and plated on BAP
in triplicate for enumeration of
colony-forming units (CFUs)/swab.
The BAP cultures were incubated
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March/April 2011
Table 2. The most commonly isolated bacteria (occurring in at least
three instruments), with their Gram stain results and illnesses they could
produce.
No. of
instruments
( n = 13) Potential diseases
Species
Gram stain/
morphology
Aureobacterium spp.
Positive/bacilli
5
Systemic infections in
immunocompromised patients
Bacillus cereus
Positive/bacilli
5
Diarrheal/emetic toxins; septicemia;
bacteremia; ocular virulence;
osteomyelitis
Bacillus megaterium
Positive/bacilli
5
Food poisoning; cerebral abscesses
Brevibacterium spp.
Positive/bacilli
11
Corneal infections; food poisoning;
endophthalmitis
Burkholderia cepacia
Negative/
bacilli
6
Pulmonary pathogen for patients with
cystic fibrosis, skin and soft tissue
infections, surgical wound infections,
and genitourinary tract infections
Cellulomonas spp.
Positive/bacilli
7
Acute cholecystitis; sepsis; infective
endocarditis; osteomyelitis
Chryseobacterium
luteola
Negative/
bacilli
8
Pseudomonas-like, opportunistic
pathogen; high drug resistance
Kocuria varians
Positive/cocci
9
Brain abscess; opportunistic pathogen
in immunocompromised patients
Micrococcus spp.
Positive/cocci
9
Opportunistic pathogens in immunocompromised patients; drug-resistant
Staphylococcus capitis
Positive/cocci
7
Septicemia; endocarditis; catheterrelated infections
Staphylococcus
epidermidis
Positive/cocci
6
Nosocomial infections; wound
infections; postsurgical infections
Staphylococcus hominis Positive/cocci
3
Septicemia; blood cultures
Staphylococcus lentus
Positive/cocci
3
Arthritis; urinary/catheter/prosthetic
joint infections
Staphylococcus
saprophyticus
Positive/cocci
3
Female urinary infections
Other
Staphylococcus spp.
Positive/cocci
10
Arthritis; catheter and prosthetic joint
infections; urinary tract infections.
at 37°C and were read at 24 and 48
hours. The Sab were incubated initially at 37°C and read at 48 hours
for yeasts, then incubated at 22°C
and read at 120 and 168 hours for
molds. The CFUs/swab were evaluated and tabulated at 48 hours by
three investigators. All BAP- and
Sab-streaked plates were scored
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at 48 hours, using the previously
described colony intensity scale
shown in Table 1.14,16-19,21
Bacteria and yeasts were identified
using standard laboratory methods,
including Gram stains and API
strips (bioMerieux, Inc.). Molds
were identified and preliminary
yeast identities were confirmed
using standard molecular techniques
(DNA analyses).
Given the numbers of microorganisms and limited funds/time,
antibiotic susceptibilities were
performed on only Gram-positive
cocci. The susceptibility procedures
used standard antibiotic-impregnated
disks on pure culture lawns of microorganisms (Kirby-Bauer test).27,28
The drugs tested were penicillin,
oxacillin (methicillin), vancomycin,
ciprofloxin, tetracycline, erythromycin, gentamicin, and azithromycin.
Zones of microbial inhibition were
measured and compared to standards
for determination of susceptibility/
resistance to individual antibiotics.
The data were analyzed statistically. Correlation coefficients (R2)
were determined using correlation
and regression analyses. The p values
were determined using the unpaired
Student’s t-test.
Results
A total of 117 sites were sampled
on 13 de-identified instruments,
which consisted of two clarinets,
two oboes, two saxophones, two
mellophones, two trombones, two
trumpets, and one cornet. The most
frequently isolated bacteria (occurring in three or more instruments)
are listed in Table 2, while the most
frequently isolated fungi (occurring
in three or more instruments) are
listed in Table 3. Examples of partial
instrument analyses (random sites)
are demonstrated in Figures 1 and 2.
A total of 442 bacterial isolates
were initially identified. After eliminating redundancies, 295 different
isolates were found in the 117 test
sites, for an average of 2.5 isolates/
site. Based on colony appearance,
morphology, Gram stain reaction,
and biochemical means (API strips),
the 295 isolates consisted of 95
(32.2%) Gram-positive cocci, 131
(44.4%) Gram-positive bacilli,
Table 3. The most commonly isolated fungi (occurring in at least three
instruments), with their type and the illnesses they could produce. Note
that many of the fungi are associated with allergic diseases and that one,
Fusarium oxysporum, produces a mycotoxin.
No. of instruments
( n = 13)
Type
Pathogenicity
Aspergillus niger
4
mold
opportunistic
Aureobasidium pullulans
3
yeast
allergenic; opportunistic
Bipolaris spp.
3
mold
allergenic; opportunistic
Candida albicans
3
yeast
opportunistic
Cochliobolus spp.
6
mold
allergenic; opportunistic
Cryptococcus laurentii
4
yeast
opportunistic
Fusarium oxysporum
7
mold
allergenic; mycotoxin; opportunistic
Paecilomyces lilacinus
5
mold
allergenic; opportunistic
Penicillium chrysogenum
11
mold
allergenic; opportunistic
Rhodotorula mucilaginosa
7
yeast
allergenic; opportunistic
Species
and 69 (23.4%) Gram-negative
bacilli; no Gram-negative cocci were
isolated. Of note, only one instrument was positive for Staphylococcus
aureus. Many of these bacterial
isolates are considered to be frank or
opportunistic pathogens.
All Gram-positive cocci (comprising 14 different species) were tested
against a battery of antimicrobials,
including methicillin. High levels of
methicillin resistance were detected
in isolates of Staphylococcus aureus
as well as in other Staphylococcus
spp. Furthermore, similar levels of
methicillin resistance were found
in Gram-positive cocci that are
generally considered to be nonpathogenic. Methicillin resistance
did not correlate with resistance
to any other antimicrobial tested
against the Gram-positive cocci.
Using standard laboratory and
molecular techniques, a total of
19 yeast isolates were detected in
eight of the 12 instruments (all six
woodwinds and both mellophones).
All of the identified yeasts could be
www.agd.org
considered as opportunistic and/or
allergenic pathogens.
The 13 instruments also yielded a
total of 58 molds. Again, all of the
mold isolates could be considered
as opportunistic and/or allergenic
pathogens. Interestingly, seven
of the mold isolates (Fusarium
oxysporum) are potential mycotoxin
producers. Mycotoxins are secondary metabolites (byproducts) of the
growth of the molds and can have
substantial toxic side effects for
plants, animals, and humans. Certain mycotoxins are also considered
carcinogenic.29
Even though the number of
instruments (13) was low, 117
individual sites were available for
statistical analyses. The statistical
analyses of the data revealed the following findings:
• There was a high level of correlation between the two methods
of quantification (touch culture
evaluations compared to serial
dilution with colony counts)
(R2 = 0.9442).
General Dentistry
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103
Infectious Disease Control Evaluation of the microbial flora found in woodwind and brass instruments
Metal mouthpiece
First water valve
First air valve
Third air valve
Second water valve
Inside bell
Case
Fig. 1. An example of cultures taken from representative sites of a mellophone. The plate on the left shows the CFUs/swab on BAP; the plate in the middle
shows the swab streak on BAP; and the plate on the right shows the swab streak on Sab. Note the quantitive and qualitative differences from site to site,
including the instrument case.
• There was a low level of correlation between the last time an
instrument was played and the
bacterial load, confirming that
some bacteria remained viable in
instruments that had not been
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March/April 2011
played in more than a month
(R 2 = 0.1520).
• There was an intermediate level
of correlation between contamination in the reed/mouthpiece
(the most proximal site), the
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instrument midpoint, and
the bell (the most distant site)
(R2 = 0.856). The reed/mouthpiece ends were consistently more
contaminated than the bell ends.
However, it should be noted that
Mouthpiece
End first joint
End second joint
Case
Fig. 2. An example of fungal streak cultures taken from representative sites of an oboe. Again, note
the quantitive and qualitative differences from site to site, including the instrument case.
both the instrument midpoints
and bells retained microorganisms
in sufficient quantities to affect
transmission, expose the musicians
to toxins, and produce disease.
• Analyses of the differences
between the bacterial loads in
woodwinds and brass instruments yielded a p value of 0.1547,
suggesting that woodwind
instruments were more heavily contaminated than brass
instruments.
• Analyses of the differences
between the bacterial loads in
reeds as compared to mouthpieces
yielded a p value of 0.0496, indicating that reeds were significantly
more heavily contaminated than
mouthpieces.
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• Analyses of the differences
between the bacterial loads in
clarinets and other woodwinds
yielded a p value of 0.0479, indicating that clarinets were significantly more heavily contaminated
than other woodwinds.
• Analyses of the differences between
the bacterial loads in clarinets and
all other instruments yielded a p
value of 0.0026, indicating that
clarinets were significantly more
heavily contaminated than all
other instruments, including brass.
• Analyses of the differences between
the bacterial loads in metal instruments (including saxophones) and
wood/plastic instruments (clarinets
and oboes) yielded a p value of
0.2376, confirming that the composition of the instrument did not
affect contamination.
• Analyses of the differences between
the bacterial loads in trombones
and all other instruments yielded a
p value of 0.2229, confirming that
contamination of trombones was
not statistically different from that
of other instruments.
• Analyses of the differences
between the bacterial loads in the
bells of the instruments and the
cases yielded a p value of 0.6864,
confirming that both sites were
equally contaminated.
• Analyses of the differences
between the bacterial loads in the
mouthpieces and the cases yielded
a p value of 0.0131, confirming
that the mouthpieces were significantly more heavily contaminated
than the cases.
• Analyses of the differences between
the bacterial loads in the reeds
and the cases yielded a p value of
0.0043, confirming that the reeds
were significantly more heavily
contaminated than the cases.
• Analyses of the differences
between the bacterial loads in
woodwind instrument cases and
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105
Infectious Disease Control Evaluation of the microbial flora found in woodwind and brass instruments
brass instrument cases yielded
a p value of 0.0008, confirming
that not only were the woodwind
instruments significantly more
heavily contaminated than brass
instruments, their cases were, too.
Discussion
The purpose of the present study was
to determine whether wind instruments are contaminated by either
frank or opportunistic pathogenic
microorganisms, which can cause significant disease in the person playing
the instrument. Such results could
be useful in determining whether
these microbes posed a danger of
a significant magnitude to warrant
periodically sterilizing the instrument
to ensure the safety of the musician.
The study followed Chart 1 and
measured microbial intensity by
both visual examination and CFUs/
swab. As confirmed by statistical
analyses of the data, there was a
statistically significant positive correlation between the two methods
of evaluating microbial load.
The results of the current study
confirmed that wind instruments
are heavily contaminated with
a wide variety of bacterial and
fungal isolates. Identification of
these microbes down to the species
level was completed; however, the
authors wish to note that using
these standard laboratory methods
did not isolate fastidious pathogens
such as spirochetes, mycoplasma,
mycobacteria, and viruses.
The results of the current study
also indicate that wind instruments
are contaminated with a number of
potentially harmful microbes, many
of which are associated with minor to
serious infectious or allergic diseases.
Furthermore, this study also found
that many of these microbes are
highly resistant to some or most of
the antibiotics normally used in general practice, including methicillin.
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March/April 2011
The medical literature is replete
with examples of carriers such as
“Typhoid Mary” who harbor and
spread potentially deadly diseases
without suffering ill effects themselves. The results of this study
found that wind instruments could
act as reservoirs of such diseases.
For this reason, prudence demands
that the presence of actual or
opportunistic pathogens must be
taken seriously in order to protect
susceptible musicians from these
microorganisms.
It must be stressed that while the
results found the heaviest contamination in the reed/mouthpiece sites,
there were sufficient microorganisms
throughout the instrument interstices and cases to warrant regular
sterilization of the entire instrument. Another unexpected finding
was that the species of microorganisms were not consistent throughout
the instruments. In other words, the
microorganisms isolated from the
sites closer to the mouthpiece end
were different from those isolated
from sites closer to the bell end.
The current study confirmed the
hypothesis that the internal components of woodwind and brass
instruments and their cases harbor
potentially pathogenic, opportunistic, and/or allergenic microorganisms. The study also confirmed
that microorganisms can be
isolated from various components
throughout instruments and their
cases and can be identified by routine laboratory methods. Because
most of the microorganisms
detected in this study are considered pathogenic, opportunistic,
and/or allergenic, sterilization of
the instrument is recommended
on a routine basis, and definitely
before an instrument is passed to a
new user. Currently, ethylene oxide
is the only agent known to sterilize
instruments effectively.30
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Because this study used deidentified instruments, no medical
histories were obtained. However,
anecdotal information from the
band teacher/leader confirmed that,
at any given time, more than 50% of
the band students had some respiratory distress (asthma or bronchitis)
that required therapy. Therefore,
additional studies must be performed to determine the microbial
concentration in the band room
before, during, and after band practice. In addition, demographic and
medical histories need to be obtained
from each band member to confirm
the anecdotal information obtained
from the band teacher/leader. Finally,
because this study analyzed wind
instruments obtained from a rural
setting, a comparable study should
be performed in an urban environment to compare findings.
Conclusion
The results of this study revealed
that wind instruments and their
cases become contaminated with
use and that this contamination can
last for extended periods of time.
Many of the bacterial and fungal
isolates must be considered to be
pathogenic, opportunistic, and/or
allergenic pathogens. In addition,
this study validated the methods
used to study contamination of
wind instruments and their cases.
Acknowledgements
Funding for this study was provided
by Lorenzo Lepore, DMD, founder
of Encore Etc., Inc.
Disclaimer
The authors have no financial interest in any of the products or manufacturers mentioned in this article
Author information
Dr. Glass is a professor of Forensic
Sciences, Pathology, and Dental
Medicine and an adjunct professor
of Microbiology, Oklahoma State
University Center for Health Sciences, Tulsa, where Dr. Conrad is
a professor of Microbiology, Dr.
Kohler is an assistant professor in
Microbiology, and Mr. Bullard is a
senior research assistant and chief
laboratory technologist.
References
1. Mr. Holland’s Opus Foundation. Available at:
http://www.mhopus.org. Accessed June 17,
2010.
2. Woolnough-King C. A microbiological survey
into the presence of clinically significant bacteria in the mouthpieces and internal surfaces of
woodwind and brass musical instruments,
1994-1995. Available at: http://www.crizz.co.
uk/micro/Intro.htm. Accessed June 17, 2010.
3. Deniz O, Savci S, Tozkoparan E, Ince DI, Ucar M,
Ciftci F. Reduced pulmonary function in wind
instrument players. Arch Med Res 2006;37(4):
506-510.
4. Gilbert TB. Breathing difficulties in wind instrument players. Md Med J 1998;47(1):23-27.
5. Glass RT. Other factors in infections: The transmission of disease. Gerodontics 1986;2(4):119-120.
6. Glass RT. Toothbrush types and retention of microorganisms: How to choose a biologically sound
toothbrush. J Okla Dent Assoc 1991;82(3):26-28.
7. Glass RT. The infected toothbrush, the infected
denture, and transmission of disease: A review.
Compendium 1992;13(7):592-598.
8. Glass RT. Transmission of dental implements and
appliances, part 1. The toothbrush. Dent Today
2004;23(9):123-127.
9. Glass RT, Carson SR, Barker RL, Peiper SC, Shapiro S. Detection of HIV proviral DNA on toothbrushes: A preliminary study. J Okla Dent Assoc
1994;84(3):17-20.
10. Glass RT, Jensen HG. More on the contaminated
toothbrush: The viral story. Quintessence Int
1988;19(10):713-716.
11. Glass RT, Martin ME, Peters LJ. Transmission of
disease in dogs by tooth-brushing. Quintessence Int 1989;20:819-824.
12. Glass RT, Min K-W, Adler V. The toothbrush, Kaposi’s sarcoma and AIDS: A case demonstrating
interesting associations. J Okla Dental Assoc
1995;86(2):22-24.
13. Glass RT, Shapiro S. Oral inflammatory diseases
and the toothbrush. J Okla Dent Assoc J 1992;
83(1):28-32.
14. Glass RT. Infection of dental implements and appliances, part 2. The denture. Dent Today 2004;
23(11):116-123.
15. Glass RT, Belobraydic K. Dilemma of denture contamination. J Okla Dent Assoc 1990;81(2):30-33.
16. Glass RT, Bullard JW, Hadley CS, Mix EW, Conrad
RS. Partial spectrum of microorganisms found in
dentures and possible disease implications. J
Am Osteopath Assoc 2001;101(2):92-94.
17. Glass RT, Bullard JW, Conrad RS, Blewett EL.
Evaluation of the sanitization effectiveness of a
denture-cleaning product on dentures contaminated with known microbial flora. An in vitro
study. Quintessence Int 2004;35(3):194-199.
18. Glass RT, Goodson LB, Bullard JW, Conrad RS.
Comparison of the effectiveness of several denture sanitizing systems: A clinical study. Compend
Contin Educ Dent 2001;22(12):1093-1102.
19. Goodson LB, Glass RT, Bullard JW, Conrad RS. A
statistical comparison of denture sanitation using a commercially available denture cleaner
with and without microwaving. Gen Dent 2003;
51(2):148-152.
20. Wendt S, Glass RT. The infected denture: How
long does it take? Quintessence Int 1987;
18(12):855-858.
21. Glass RT, Bullard JW, Conrad RS. The contamination of protective mouthguards: A characterization of the microbiota found in football players’
protective mouthguards as compared to the oral
microbiota found in first-year medical students.
J Am Dent Inst Cont Educ 2006;93:23-38.
22. Glass RT, Conrad RS, Wood CR, Warren AJ,
Kohler GA, Bullard JW, Benson G, Gulden JM.
Protective athletic mouthguards: Do they cause
harm? Sports Health 2009;1(5):411-415.
23. Glass RT, Wood CR, Bullard JW, Conrad RS. Possible disease transmission by contaminated
mouthguards in two young football players. Gen
Dent 2007;55(5):436-440.
24. Glass RT. Your heart, your toothbrush, your denture—Even your protective athletic mouthguard—Are they related in disease? Lecture at
the Ontario Dental Association 2010 annual
spring meeting. Toronto, Canada, May 13, 2010.
25. Roberts RR, Hota B, Ahmad I, Scott RD, Foster SD,
Abbasi F, Schabowski S, Kampe LM, Ciavarella
GG, Supino M, Naples J, Cordell R, Levy SB, Weinstein RA. Hospital and societal costs of antimicrobial-resistant infections in a Chicago teaching
hospital: Implications for antibiotic stewardship.
Clin Infect Dis 2009;49(8):1175-1184.
26. Antibiotic-resistant infections cost the U.S.
health system in excess of $20 billion annually.
Available at: http://www.prnewswire.com/newsreleases/antibiotic-resistant-infections-cost-theus-healthcare-system-in-excess-of-20-billion-annually-64727562.html. Accessed June 17, 2010.
27. Bauer AW, Perry DM, Kirby WM. Single-disk antibiotic-sensitivity testing of staphylococci: An
analysis of technique and results. AMA Arch
Intern Med 1959;104(2):208-216.
28. Bauer AW, Kirby WM, Sherris JC, Turck M. Antibiotic susceptibility testing by a standardized
single disk method. Am J Clin Pathol 1966;45(4):
493-496.
29. Grain fungal diseases & mycotoxin reference.
September 2006. Available at: http://archive.
gipsa.usda.gov/pubs/mycobook.pdf. Accessed
November 2, 2010.
30. Glass RT. Evaluation of the microbial flora found
in band musical instruments (woodwinds and
brass) and their potential to transmit diseases.
Results of a preliminary study. Testimony before
the Joint Committee on Education of the Massachusetts State Legislature, 111 Bill, Boston,
MA, 5/26/09.
Manufacturers
bioMerieux, Durham, NC
800.682.2666, www.biomerieux-usa.com
COMMENT
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General Dentistry
March/April 2011
107
self CDE
2 HOURS instruction
CREDIT
Exercise No. 279
Infectious Disease Control
Subject Code 148
The 15 questions for this exercise are based on the article
“Evaluation of the microbial flora found in woodwind and
brass instruments and their potential to transmit diseases”
on pages 100-107. This exercise was developed by Steven
E. Holbrook, DMD, MAGD, in association with the General
Dentistry Self-Instruction committee.
4.
How many of the instruments yielded yeast isolates
that could be considered opportunistic and/or
allergenic pathogens?
A. 2
B. 4
C. 8
D. 12
Reading the article and successfully completing the
exercise will enable you to:
• recognize the potential for disease transmission from
contaminated band instruments;
• recognize the need for periodic sterilization of band
instruments;
• identify the pattern of distribution of potential
pathogens in and among band instruments; and
• understand the possible consequences to patients from
exposure to potential pathogens from contaminated
band instruments.
5.
The reed/mouthpiece ends of the instruments
were consistently more contaminated than the bell
ends. Both the midpoints and the bell ends did not
retain microorganisms in sufficient quantities to
produce disease.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
6.
What percentage of mold isolates found in the
instruments were potential mycotoxin producers?
A. 12
B. 24
C. 48
D. 96
7.
Which band instruments were more heavily
contaminated with bacteria?
A. Brass
B. Percussion
C. Woodwinds
D. Strings
8.
Which of the following woodwind instruments was
most contaminated with bacteria?
A. Oboes
B. Clarinets
C. Trombones
D. Saxophones
9.
Analysis of the bacterial loads revealed that
which of the following did not affect bacterial
contamination?
A. Composition of the instruments
B. Length of the reed
C. Diameter of the mouthpiece
D. Shape of the bell
1.
2.
3.
108
What is the only effective method of band
instrument sterilization?
A. Dry heat
B. Moist heat
C. Ethylene oxide
D. Cold sterilization
In a recent study of protective athletic
mouthguards, 71% of non-aureus Staphylococcus
and Micrococcus spp. were resistant to
A. methicillin.
B. glutaraldehyde.
C. gentamycin.
D. triclosan.
High levels of methicillin resistance were found in
isolates of
A. Staphylococcus aureus.
B. Streptococcus mutans.
C. Treponema denticola.
D. Fusobacterium nucleatum.
March/April 2011
General Dentistry
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10.
11.
12.
The analysis of bacterial loads confirmed all of the
following except:
A. Reeds were significantly more contaminated
than their cases
B. Mouthpieces were significantly more
contaminated than their cases
C. Woodwind cases were significantly more
contaminated than brass cases
D. The band room was significantly more
contaminated than other classrooms
Studies have confirmed a relationship between
playing band instruments and breathing
difficulties. This pathology is the result of playing
contaminated band instruments.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
What do the results of the study indicate?
A. Band instruments were contaminated with
pathogenic microbes
B. Periodic sterilization of band instruments is
not indicated
C. Asthma in band students is caused by
contaminated instruments
D. Band students are more susceptable to
opportunistic pathogens
13.
All of the following bacterial isolates were
identified from internal components or cases of
band instruments or except:
A. Gram-positive cocci
B. Gram-positive bacilli
C. Gram-negative cocci
D. Gram-negative bacilli
14.
Bacterial load analysis confirmed that the bells of
instruments were equally as contaminated as their
A. mouthpieces.
B. valves.
C. reeds.
D. cases.
15.
What percentage of hospitalized patients from
a 2000 study were found to have antimicrobialresistant infections?
A. 3.5
B. 7.5
C. 13.5
D. 16.5
Answer form and Instructions are on pages 159-160.
Answers for this exercise must be received by February 29, 2012.
To enroll in Self-Instruction, click here.
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General Dentistry
March/April 2011
109
oral Diagnosis
What every dentist should know about zinc
Amar Patel, DDS
n
J. Anthony von Fraunhofer, MSc, PhD
Zinc plays an important role in human physiology, from its involvement in the proper function of the immune system to its role in
cellular growth, cell proliferation, and cell apoptosis as well as its
essential role in the activity of numerous zinc-binding proteins.
However, zinc also plays a key pathophysiological role in major
neurological disorders and diabetes. Zinc deficiency is a worldwide
problem, whereas excessive intake of zinc is relatively rare. Many
patients are exposed to zinc on a regular basis through dentistry
Z
inc is one of the essential trace
metals in the human body;
other essential trace metals
include chromium, selenium, manganese, and copper.1 Zinc can be
found in large quantities throughout the human diet; major sources
include oysters, beef, lobster, pork,
cereal, yogurt, fish, and eggs.2 Zinc
deficiency, a worldwide problem
that affects approximately 4 million
people in the U.S. alone, is seen
in populations having diets low in
red meat and rich in dietary fiber
and phytate (inositol hexaphosphoric acid). Zinc deficiency also
is observed in alcoholism, chronic
renal disease, sickle cell anemia,
and malabsorption conditions. The
initial manifestations of zinc deficiency are taste and olfactory dysfunctions, but as severity increases,
zinc deficiency causes a variety of
problems, including impaired brain
growth, anorexia, growth retardation, hypogonadism, and delayed
sexual maturity.
Research has shown that zinc
participates in more than 300
enzymatic reactions; in fact, zinc is
present in one form or another in
each of the six classes of enzymes.3
Within these classes, zinc heavily
influences carbohydrate and energy
110
March/April 2011
n
Nasir Bashirelahi, PhD
as a result of its use in certain restorative materials, mouthwashes,
toothpastes and, notably, denture adhesives. Of particular importance
to dental professionals are various case reports concerning the
neurologic effects of excess zinc intake by patients who routinely use
large quantities of zinc-containing denture adhesives. This review
presents relevant information concerning the use of zinc in dentistry.
Received: January 27, 2010
Accepted: April 26, 2010
metabolism, protein degradation
and synthesis, nucleic acid synthesis,
and intracellular transportation
while providing antioxidant activity.1
The pancreatic system also relies
on zinc for exocrine and endocrine
functions. Another zinc-dependent
process is spermatogenesis, as
zinc is important for testosterone
metabolism.1 The ubiquitous presence of zinc in the human body has
led researchers to study its relation
to various forms of cancer, such as
prostate and oral cancers.4,5 The
homeostatic properties of zinc allow
the body to reduce excretion of zinc
during times of insufficiency and
increase excretion during periods of
excess intake.6
Absorption of zinc, copper, and
iron via the diet is an active process
with similar transport mechanisms.1
Excess zinc intake, however, has
been linked to copper insufficiency,
due to the similarity in absorption
patterns in the gastrointestinal
tract for the two metals.7 Several
studies have connected the link
between copper-deficient anemia
and neutropenia to an increase in
zinc intake.8,9 Of direct concern
to dental professionals, however,
has been the recent discovery of
neurologic disorders resulting from
General Dentistry
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excessive use of denture adhesives;
these products can contain high
leachable zinc contents that can
cause copper deficiencies.10
The recommended daily allowance (RDA) of zinc for adult males
(ages 19–70) is 11 mg; for adult
females, the RDA is 8 mg.11 People
with diets rich in phytate (for example, vegetable-based diets) could
experience mineral deficiencies,
typically in developing countries.
Since phytate, present in vegetarian
diets, is a strong chelator of zinc
(as well as calcium, magnesium,
and iron), vegetarians and athletes
with high-carbohydrate diets could
require zinc supplementation.
Zinc supplements are available in
a variety of forms; dietary supplements commonly are based on zinc
gluconate, zinc sulfate, or zinc acetate, although the percentage of elemental zinc varies each compound.
For example, zinc sulfate contains
approximately 23% elemental
zinc.12 Other supplemental sources
of zinc include OTC cold remedies
such as throat lozenges, nasal sprays,
and gels. Recent controversy over
the side effects of nasal sprays
containing zinc has caused the FDA
to issue a warning to consumers
about anosmia resulting from use of
the sprays. As a result, the producer
of these nasal sprays has pulled its
products from the market.12
Excessive zinc intake causes toxicity, which commonly manifests as
nausea, stomachache, and mouth
irritation; long-term excessive
ingestion can lead to neurological
complications. Large doses of zinc
supplements are used to treat celiac
disease, sickle cell anemia, and
Wilson’s disease. Although chronic
therapeutic use of zinc can cause
hypocupremia, microcytic anemia,
and neutropenia, such conditions
respond to copper supplementation
and are reversible.
Zinc use in dentistry
An important enzyme that requires
the presence of zinc is Zn-superoxide dismutase (SOD), which is
critical for oxidation-reduction reactions within the body. This enzyme
converts superoxide into oxygen
and peroxide molecules, eliminating free radicals.13 Endodontic
studies performed on healthy and
symptomatic dental pulp showed
variations in the expression and concentrations of SOD.14 The benefits
of SOD include antioxidant and
anti-inflammatory properties and
improvements to immune response
and brain function. The enzyme
is approximately two times more
active in teeth with healthy dental
pulp than in those with irreversible,
symptomatic pulpitis.
In addition to its function
within the dental pulp, SOD has
played a critical role in other oral
health diseases. SOD levels have
been studied in patients with oral
squamous cell carcinoma (OSCC)
and in smokers with periodontal
disease. Patients with OSCC
showed decreased levels of SOD
in tissue and blood samples; the
study authors suggested that active
progression of OSCC increases
oxidative stress on patients who
might already have deficient antioxidant mechanisms.15 Cigarette
smokers with chronic periodontitis
were found to have decreased
levels of SOD compared to healthy
nonsmokers.16 The findings of
this study suggest that smoking
creates oxidative stress within the
oral cavity and results in SOD
deficiency, which can predispose
patients to periodontitis.
Zinc is also vital in the formation
of metallothioneins (MT), which
likewise have antioxidant properties.17 A recent study used immuneassays to determine the expression
of MT with p53 in various forms
of oral cancer. The results indicated
that there was a correlation between
MT prevalence and the aggressiveness of oral cancers.4
Zinc and caries
Cariogenic diets deficient in zinc
have demonstrated increased rates
of smooth surface enamel caries in
mandibular molars.18 This finding
suggests that zinc plays a critical
role in posteruption mineralization.
Other studies indicate that zinc is
excreted into the saliva in higher
concentrations for carious patients;
it has been postulated that remineralization with zinc should be considered in patients with active caries.19
Zinc and recurrent
apthous ulcers
Daily supplementation with 220
mg of zinc for a period of one
month has been found to be beneficial for patients subject to recurrent apthous ulcers (RAU).3 This
therapy has been shown to increase
zinc levels in serum, albumin,
and alkaline phosphatase activity;
clinical observation confirmed
that lesions disappeared and recurrence rates dropped following zinc
supplementation.
www.agd.org
Zinc and dentifrices
Zinc can provide additional
benefits for the oral mucosa, as it
has demonstrated the ability to
reduce the inflammatory activity of
surfactants.20 Studies with sodium
laurel sulfate, a common ingredient
in oral mouthrinses and dentifrices,
indicated that the addition of
zinc and triclosan contributed to
a protective effect on oral mucosa
through reduced erythema and
inflammation. Another study evaluating the antiplaque properties of
various ingredients in mouthrinses
discovered that the addition of zinc
citrate in conjunction with triclosan
decreased plaque formation.21 The
same study found that the addition
of zinc citrate decreased inflammatory responses within the oral
mucosa. More recent studies have
focused on the protective effect
of zinc citrate when it is included
in dentifrices; patients using a
zinc citrate dentifrice exhibited a
27–49% decrease in anaerobic and
streptococcal flora.22
Zinc and restorative materials
The combination of the adverse
effects from zinc deficiencies and
excessive zinc intake with the
delicate balance the body uses to
maintain zinc homeostasis indicate
that the presence of zinc in dental
products could have negative
systemic effects. This is particularly
true for dental products that could
constitute nontraditional sources
of zinc uptake, especially if such
products are abused.
Zinc is a widely used element
in dental products, notably in
inorganic dental cements such as
zinc phosphate and polycarboxylate cements (luting agents based
in zinc oxide), zinc oxide-eugenol
(ZOE) temporary cements, and
ZOE endodontic filling materials.
At one time, zinc was incorporated
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111
oral Diagnosis What every dentist should know about zinc
in conventional (low copper) dental
amalgams, but these materials have
largely been displaced by high
copper amalgams. Another major
use of zinc in dental materials is
in denture adhesives or fixatives,
predominantly in the form of the
triple salt formulation comprising
zinc, magnesium, and calcium salts
of gantrez acid (polymethyl vinyl
ether maleic acid).
Zinc oxide, used in permanent
and provisional cements and
temporary filling materials, has
been shown to possess inherent
antimicrobial effects.23 Further, the
antibacterial properties of zinc oxide
are being tested outside the field
of dentistry for their effectiveness
against a variety of bacteria, including Escherichia coli.24,25 It should
be noted that polymer-based sealer
materials are being increasingly used
in endodontics, with a trend away
from traditional zinc oxide-based
materials, despite certain clinical
advantages. Interestingly, one criticism leveled against ZOE root canal
sealers—cytotoxicity—has been
shown to be caused by the eugenol
component, not zinc oxide.26
The neurotoxic effects of zinc
have been demonstrated by in vitro
studies of dental amalgam placed
in cortical cell cultures of glial and
neuronal cells.27 Although amalgam
contains a variety of potentially
neurotoxic metals (mercury, copper,
tin, silver, and zinc), zinc leakage
caused the toxicity effects when
amalgam was placed in direct contact with neural cells. However, due
to zinc’s complex interaction with
the body, a clear dose-dependent
toxicity was not established. This
study did not establish that the
clinical use of amalgam was linked
to neurotoxicity in vivo; instead,
it alerted practitioners to the fact
that mercury is not the most neurotoxic metal in dental amalgam.
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March/April 2011
Additionally, it was suggested that
incorporation of a zinc chelator
within the amalgam restorative
material would reduce concerns over
neurotoxic effects arising from zinc
leaching due to leakage effects.27
In an effort to provide further
understanding of potential adverse
effects from zinc release, a study was
performed using dentin as a substrate to examine the in vitro release
of zinc from restorative materials.28
The authors concluded that without
the presence of dentin, high concentrations of zinc were released into
solution. In some instances, these
levels exceeded the cytotoxic levels
for cells. However, with the presence
of dentin, the release of zinc was
greatly diminished.28
A case report from Japan in
2005 reported the development of
palmoplantar pustulosis (PPP) in
a patient, the cause of which was
ascribed to dental restorations. The
clinical symptoms of PPP are the
presentation of pustules, vesicles,
and scaly erythema over the palmar
and sole regions. A forearm allergen
test administered to the patient
determined that the zinc contained
in the dental restorations caused the
condition, which was alleviated following removal of the restorations.29
Zinc and denture adhesives
In recent years, the neurology
literature has published case reports
on the examination of patients
experiencing hypocupremia and its
neurologic side effects.30-32 These
studies are of particular interest to
dentistry because the source of zinc
uptake was determined to be excessive use of denture adhesives. In
at least one case, excessive use was
defined as patient administration of
two or three tubes of denture adhesive per week over a period of years.
The actual prevalence of denture
adhesive-induced hypocupremia is
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unknown, but it may be higher than
anticipated if patient use of such
products greatly exceeds recommended dosages.
The instructions for use of
denture adhesives (packaged with
the product) suggest that optimal
use involves placing a thin film or a
series of dots across the intaglio surface and/or within the sulcus of the
denture. When this recommendation
is followed, approximately 0.5–1.5 g
of denture adhesive would be placed
on the denture. Since the average
tube of denture adhesive contains 68
g of paste, a single tube should last
a patient 3–10 weeks with daily use,
although actual consumption would
depend on the number of adhesive
applications per day.30 It is only
recently that packaging of denture
adhesives included warnings regarding overuse of these products and
potential adverse systemic effects.
The corollary of the complex
exchange mechanism of absorption
in gut cells is that an excess uptake
of zinc will lead to an acquired
copper deficiency. This competitive
binding between zinc and copper is
used therapeutically for individuals
with Wilson’s disease; affected individuals are prescribed zinc supplements to decrease serum copper
levels. In comparison, patients
reported to have abused denture
adhesive had zinc intakes that
were 5–23 times the supplemental
dosing provided to patients with
Wilson’s disease.31
Systemic effects arising from
copper deficiency have been previously described and were attributed
to hematologic and neurologic
disorders.31 Although the clinical
symptoms—notably neurological effects associated with copper
deficiency—have not always been
described in detail, these symptoms
have included myelopolyneuropathy, optic neuritis, motor neuron
disease, and peripheral neuropathy.
Commonly, these symptoms
initially manifest as paresis of the
lower extremities that progresses to
include the upper extremities. These
patients also have reported a loss of
balance and varying symptoms of
myelopathy involving the corticospinal tract and dorsal columns.31
Hyperzincemia is now considered
to be the second most common
cause of copper deficiency myelopathy, with the leading cause being
a history of upper gastrointestinal
surgeries.31 When patients suffering from hyperzincemia were
taken off the denture adhesive and
given copper supplements, serum
levels for both metals returned to
normal.30 The timing of diagnosis
and immediate treatment are critical
in preventing irrevocable neurologic
changes associated with zinc.31
In the three studies summarized
here, there were varying degrees of
neurologic improvement after cessation of denture adhesive use. As
noted, the estimated daily exposure
of zinc from denture adhesive use
for these patients ranged from
350–1,700 mg. While this intake is
very high, it does not directly reflect
the uptake dosage, as the mechanism of zinc uptake from denture
adhesive through the oral mucosa
has not been quantified.31
Summary
Zinc has great nutritional importance and is usually absorbed into
the body through dietary intake.
However, the presence of zinc in a
number of dental materials, especially denture adhesives, appears to
provide an additional source of zinc
intake. Pathological consequences
of excessive zinc intake, particularly
its possible interference with the
absorption of copper arising from
excessive use of denture adhesive
creams, should be a matter of
concern for all dentists who treat
patients with dentures. Zinc excess
might be an example of an induced
essential trace metal imbalance that
could affect the entire body.
When encountering neurological
syndromes in patients, dentists
should consider the possibility of
hyperzincemia due to excessive zinc
intake. It must be noted, however,
that this issue has been controversial
and litigious. Currently, the FDA
has issued no warnings regarding
the use of denture adhesives, but
dentists should admonish their
patients to limit the use of denture
adhesives in accordance with
manufacturers’ instructions. Finally,
the studies cited here indicate that
the use of essential trace metals and
vitamins should be considered holistically, not as individual elements.
Author information
Dr. Patel is a resident, Baltimore
College of Dental Surgery,
University of Maryland at
Baltimore, where Dr. von
Fraunhofer is professor emeritus
of biomaterials science and
Dr. Bashirelahi is a professor of
biochemistry.
References
1. Baynes J, Dominiczak MH. Medical biochemistry.
Philadelphia: Mosby;2009.
2. American Optometric Association. Zinc. Available at: www.aoa.org/x11848.xml. Accessed
November 15, 2009.
3. Haase H, Overbeck S, Rink L. Zinc supplementation for treatment or prevention of disease: Current status and future perspectives. Exper
Gerontol 2008;43(5):394-408.
4. Cardoso SV, Silveira-Junior JB, De Carvalho
Machado V, De-Paula AM, Loyola AM, De Aguiar
MC. Expression of metallothionein and p53 antigens are correlated in oral squamous cell carcinoma. Anticancer Res 2009;29(4):1189-1193.
5. Ho E, Song Y. Zinc and prostatic cancer. Cur
Opin Clin Nutrition Metabol Care 2009;12(6):
640-645.
6. Liuzzi JP, Cousins RJ. Mammalian zinc transporters. Annu Rev Nutr 2004;24:151-172.
7. Fosmire GJ. Zinc toxicity. Am J Clin Nutrition
1990;51(2):225-227.
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8. Willis MS, Monaghan SA, Miller ML, McKenna
RW, Perkins WD, Levinson BS, Bhushan V, Kroft
SH. Zinc-induced copper deficiency: A report of
three cases intially recognized on bone marrow
examination. Am J Clin Pathol 2005;123(1):
125-131.
9. Imataki O, Ohnishi H, Kitanaka A, Kubota Y, Ishida T, Tanaka T. Pancytopenia complicated with
peripheral neuropathy due to copper deficiency:
Clinical diagnostic review. Intern Med 2008;
47(23):2063-2065.
10. Winston GP, Jaiser SR. Copper deficiency: An unusual case of myelopathy with neuropathy. Ann
Clin Biochem 2008;45(Pt 6):616-618.
11. Trumbo P, Yates AA, Schlicker S, Poos M. Dietary
reference intakes: Vitamin A, vitamin K, arsenic,
boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium,
and zinc. J Am Diet Assoc 2001;101(3):294301.
12. National Institutes of Health. NIH Office of Dietary Supplements: Zinc. http://dietarysupplements.info.nih.gov/FactSheets/Zinc.asp.
Accessed November 12, 2009.
13. Schwartz JR, Marsh RG, Draelos ZD. Zinc and
skin health: Overview of physiology and pharmacology. Dermatol Surg 2005;31(7 Pt 2):837847.
14. Varvara G, Traini T, Esposito P, Caputi S, Perinetti
G. Copper-zinc superoxide dismutase activity in
healthy and inflamed human dental pulp. Int
Endod J 2005;38(3):195-199.
15. Gokul S, Patil V, Jailkhani R, Hallikeri K, Kattappagari KK. Oxidant-antioxidant status in blood
and tumor tissue of oral squamous cell carcinoma patients. Oral Dis 2010;16(1):29-33.
16. Agnihotri R, Pandurang P, Kamath SU, Goyal R,
Ballal S, Shanbhogue AY, Kamath U, Bhat GS,
Bhat KM. Association of cigarette smoking with
superoxide dismutase enzyme levels in subjects
with chronic periodontitis. J Periodontol 2009;
80(4):657-662.
17. Tapiero H, Tew KD. Trace elements in human
physiology and pathology: Zinc and metallothioneins. Biomed Pharmacother 2003;57(9):399411.
18. Fang MM, Lei KY, Kilgore LT. Effects of zinc deficiency on dental caries in rats. J Nutr 1980;
110(5):1032-1036.
19. Gomershtein V, Maksimovskii IuM. Zinc and caries [article in Russian]. Stomatologiia (Mosk)
1989;68(6):52-54.
20. Skaare AB, Rolla G, Barkvoll P. The influence of
triclosan, zinc, or propylene glycol on oral mucosa exposed to sodium lauryl sulphate. Eur J Oral
Sci 1997;105(5 Pt 2):527-533.
21. Kjaerheim V, Skaare A, Barkvoll P, Rolla G. Antiplaque, antibacterial, and anti-inflammatory
properties of triclosan mouthrinses in combination with zinc citrate or polyvinylmethylether
maleic acid (PVM-MA) copolymer. Eur J Oral Sci
1996;104(5-6):529-534.
22. Sreenivasan PK, Furgang D, Markowitz K, McKiernan M, Tischio-Bereski D, Devizio W, Fine D.
Clinical anti-microbial efficacy of a new zinc
citrate dentifrice. Clin Oral Investig 2009;13(2):
195-202.
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23. Daugela P, Oziunas R, Zekonis G. Antibacterial
potential of contemporary dental luting cements. Stomatologija 2008;10(1):16-21.
24. Liu Y, He L, Mustapha A, Li H, Hu ZQ, Lin M. Antibacterial activities of zinc oxide nanoparticles
against Escherichia coli O157:H7. J Appl Microbiol 2009;107(4):1193-1201.
25. Reddy KM, Feris K, Bell J, Wingett DG, Hanley C,
Punnoose A. Selective toxicity of zinc oxide
nanoparticles to prokaryotic and eukaryotic
systems. Appl Phys Lett 2007;90(213902):
2139021-2139023.
26. Gulati N, Chandra S, Aggarwal PK, Jaiswal JN,
Singh M. Cytotoxicity of eugenol in sealer containing zinc-oxide. Endod Dent Traumatol 1991;
7(4):181-185.
27. Nations SP, Boyer PJ, Love LA, Burritt MF, Butz
JA, Wolfe GI, Hynan LS, Reisch J, Trivedi JR. Denture cream: An unusual source of excess zinc,
leading to hypocupremia and neurologic disease. Neurol 2008;71(9):639-643.
28. Hedera P, Peltier A, Fink JK, Wilcock S, London Z,
Brewer GJ. Myelopolyneuropathy and pancytopenia due to copper deficiency and high zinc
levels of unknown origin II. The denture cream
is a primary source of excessive zinc. Neurotoxicol 2009;30(6):996-999.
29. Yanagi T, Shimizu T, Abe R, Shimizu H. Zinc dental fillings and palmoplantar pustulosis. Lancet
2005;366(9490):1050.
30. Lobner D, Asrari M. Neurotoxicity of dental
amalgam mediated by zinc. J Dent Res 2003;
82(3):243-246.
31. Meryon SD, Jakeman KJ. Zinc release from dental restorative materials in vitro. J Biomed Mater
Res 1986;20(3):285-291.
32. Al-Nazhan S, Spangberg L. Cytotoxicity Study of
AH26 and amalgam, in vitro, using human periodontal ligament fibroblasts. Saudi Dent J 1990;
2(2):48-51.
COMMENT
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Dentinal Hypersensitivity & treatment
CDE
2 HOURS
CREDIT
Dentin hypersensitivity and its management
C.H. Chu, BDS, MAGD, ABGD
n
Anty Lam, RDH, BSc, MPH
Dentin hypersensitivity is a common patient complaint that is more
prevalent than the profession realizes. It is important for dentists
to diagnose dentin hypersensitivity by exclusion and provide
appropriate treatment recommendations for patients. Various
treatment methods have been proposed but no universally accepted
desensitizing agent or treatment has been identified. When a patient
has symptoms that can be attributed to dentin hypersensitivity,
A
ddy and Urquhart defined
dentin hypersensitivity as
short, sharp pain arising from
exposed dentin, typically in response
to chemical, thermal, or osmotic
stimuli that cannot be explained
as arising from any other forms of
dental defect or pathology.1 Dentin
hypersensitivity is a prevalent oral
problem, affecting more than 40%
of adults worldwide and more than
40 million people in the United
States.2-4 It has been reported to
afflict 15–20% of the adult population, typically those between the ages
of 20 and 50, with a peak incidence
between the ages of 30 and 39.5
Some studies have reported prevalence levels as high as 68%.6 Patients
with periodontal diseases are at particularly high risk for dentin hypersensitivity, and studies report that
over 70% of periodontal patients
experience it.7,8 The condition can
last for days to weeks or indefinitely,
unless treatments are provided.
Although patients who experience
dentin hypersensitivity may mention it during a routine dental visit,
most of them do not specifically
seek treatment for this problem,
most likely because they do not
view it as a significant dental health
problem.9 However, dentin hypersensitivity can significantly affect an
n
Edward C.M. Lo, BDS, MDS, PhD
a thorough clinical examination should be carried out to rule out
other likely causes prior to diagnosis and treatment. Depending on
the identified cause, a combination of individualized instructions
on proper oral health behaviors, use of at-home products, and
professional treatment may be required to manage the problem.
Received: May 18, 2010
Accepted: August 3, 2010
individual’s quality of life—it limits
dietary choices, can impede effective
oral hygiene, and can have a negative effect on esthetics.
The incidence of dentin hypersensitivity is expected to rise as diets
change; however, prevention of both
caries and periodontal disease may
result in improved oral health status
and retention and functionality of
the dentition.
In a recent random telephone
survey, 62% of the respondents
reported a slight twinge upon
consumption of hot, cold, sour, or
sweet food, all of which can cause
dentin hypersensitivity.10 Further, it
was found that the most common
initiating factor for dentin hypersensitivity among the respondents
was consumption of cold drinks.
Studies have reported that premolars are most commonly affected by
dentin hypersensitivity.11 However,
another study found that mandibular incisors were most commonly
affected and determined that most
hypersensitive areas were found on
the facial surface of teeth.10
Dentin hypersensitivity usually
occurs in patients between the
ages of 30 and 40; the incidence
then declines with age.11 The most
likely reason for this decrease may
be related to changes in the pulp,
www.agd.org
in particular, dentinal sclerosis and
the development of secondary or
tertiary dentin.
In 2009, the Academy of General
Dentistry (AGD) conducted a
member survey on dentin hypersensitivity.12 Among the 710 members
who responded, nearly 60% noted
that the frequency of tooth erosion
had increased over the last five
years. However, more than half of
the respondents (56%) reported
that less than 25% of their patients
seek information from them regarding dentin hypersensitivity. Thirty
percent of the respondents reported
that the youngest age group to
demonstrate tooth surface loss was
the one covering ages 5–7.
Etiology
In a normal tooth, dentin is
covered in the crown by enamel
and, in most areas of the root, by
a thin layer of cementum. Each
tooth contains many thousands
of dentinal tubules, which are
microscopic tubular structures
that radiate outward from the pulp
(Fig. 1). These dentinal tubules are
typically 0.5–2.0 μ in diameter
and are connected to the pulp by a
plasma-like biological fluid. Each
tubule contains a cytoplasmic cell
process called a Tomes’ fiber and
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115
Dentinal Hypersensitivity & treatment Dentin hypersensitivity and its management
Fig. 1. A scanning electron microscopy image
of exposed dentin surface (2000x).
Fig. 4. Dental erosion due to frequent intake of
acidic beverages.
Fig. 2. Enamel loss exposing dentin in molars.
Fig. 5. Pain elicited by movement of fluid in
dentinal tubules.
Fig. 3. Gingival recession exposing tooth roots.
yet been fully determined. Studies
have attempted to evaluate pulpal
histology after bleaching but have
produced contradictory results.14
However, many researchers have suggested that inflammatory mediators
can play an important role in causing pain related to hypersensitivity.15
Mechanism of dentin
hypersensitivity
an odontoblast that communicates
with the pulp.
There are two types of nerve fibers
within the dentinal tubules, myelinated (A-fibers) and unmyelinated
(C-fibers). The A-fibers are responsible for the sensation of dentin
hypersensitivity, perceived as pain in
response to all stimuli. Depending
on the depth, approximately 30,000
tubules can be found in 1 mm2
in a cross-section of dentin. One
study found the number of open
dentinal tubules per surface area in
the exposed dentin surface of teeth
with dentin hypersensitivity to be
eight times that of teeth that did not
respond to stimuli.13
The primary causes of dentin
hypersensitivity are enamel loss on
the tooth crown (Fig. 2) and gingival recession exposing the tooth
root (Fig. 3). Enamel loss can be a
result of aggressive and/or incorrect
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March/April 2011
toothbrushing, overconsumption of
acidic foods, and/or tooth grinding
caused by stress and parafunctional
behaviors. A recent study found
that many people frequently ingest
fruits, lemon tea, fruit juice, and
soft drinks.10 The frequent intake of
these foods and beverages can cause
tooth erosion and dentin hypersensitivity (Fig. 4). In addition,
some dental restorative and surgical
procedures can cause the gingiva to
recede from the normal position at
the crown-root junction. When the
root is exposed to the oral environment, the cementum covering the
root can be removed easily, resulting
in exposure of the underlying dentin
and dentin hypersensitivity.
Dentin hypersensitivity also has
been reported during and following external tooth bleaching. The
mechanisms of tooth sensitivity after
external tooth bleaching have not
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The exact mechanism of dentin
hypersensitivity is still unclear
and continues to be the subject of
research. One commonly accepted
theory is Brannstrom’s hydrodynamic theory, which suggests that
changes in the fluid flow in dentinal
tubules can trigger pain receptors
present on nerve endings (located
at the pulpal aspect) to fire nerve
impulses, thereby eliciting pain
(Fig. 5).16 This hydrodynamic flow
can be increased by changes in temperature, humidity, air pressure, and
osmotic pressure or by forces acting
on the tooth. Physical pressure
and hot or cold foods and drinks
are typical triggers in people with
dentin hypersensitivity.15
Managing dentin
hypersensitivity
According to the 2009 AGD
member survey, only 20% of
dentists reported areas that patients
indicated were sensitive during a
Table 1. Recommendations to prevent dentin hypersensitivity. (Adapted from: Drisko CH. Dentine
hypersensitivity—Dental hygiene and periodontal considerations. Int Dent J 2002;52(5):385-393.)
Suggestions for patients
Suggestions for dental professionals
Avoid using large amounts of toothpaste or reapplying it during
brushing
Avoid overinstrumenting the root surfaces during scaling and root
planing, particularly in the cervical area of the tooth
Avoid medium- or hard-bristle toothbrushes
Avoid overpolishing exposed dentin during stain removal
Avoid brushing teeth immediately after ingesting acidic foods
Avoid violating the biological width during restoration placement, as
this can cause recession
Avoid brushing teeth with excessive pressure
Avoid excessive flossing or improper use of other interproximal
cleaning devices
Avoid burning the gingival tissues during in-office bleaching
Advise patients to be careful when using at-home bleaching products
Avoid picking or scratching at the gingiva or using toothpicks
inappropriately
dental examination.12 Most cases
(56%) of dentin hypersensitivity
were detected by the patient indicating that an area was sensitive. The
two most frequent initial physical
symptoms of dentin hypersensitivity were teeth cupping (52%) and
glassy or translucent tooth appearance (34%). The two most common
causes of dentin hypersensitivity
were aggressive toothbrushing
(34%) and/or drinking too many
acidic beverages (19%). According
to the respondents, many patients
(56%) managed their sensitivity
by avoiding consumption of cold
foods or beverages. The most
common strategy for professional
dental management of dentin
hypersensitivity was the application
of topical fluoride (39%). Although
abrasion from incorrect toothbrushing was common, only 20% of the
respondents provided counseling
specifically on brushing.
In 2003, the Canadian Advisory
Board on Dentin Hypersensitivity
(CABDH) conducted a survey of
dentists and dental hygienists in
Canada using a 66-item questionnaire. The survey found that fewer
than half of the 542 respondents
(331 dentists and 211 dental
hygienists) considered a differential
diagnosis for dentin hypersensitivity,
even though it is by definition a
diagnosis of exclusion.17 The survey
also revealed that many respondents
(64% of dentists and 77% of hygienists) incorrectly cited bruxism and
malocclusion as triggers for dentin
hypersensitivity, while only a small
percentage of the respondents (7%
of dentists and 5% of dental hygienists) could correctly identify erosion
as a primary cause. Furthermore,
17% of dentists and 48% of hygienists were unable to identify the
accepted theory of hypersensitivity.
Approximately half of the respondents reported that they lacked the
confidence to manage a patient’s
pain caused by dentin hypersensitivity. Also, only half of the respondents
reported that they would try to
modify the patient’s predisposing
factors to control the pain.
This survey also revealed a lack
of understanding of desensitizing
toothpastes among the respondents.17 Most dentists (56%) and
dental hygienists (68%) thought
that these toothpastes could prevent
dentin hypersensitivity, while 31%
of dentists and 16% of hygienists
believed that desensitizing toothpastes could not provide relief from
dentin hypersensitivity. These results
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indicate a need for continued dental
education on the diagnosis and management of dentin hypersensitivity.
Dentin hypersensitivity meets all
of the criteria necessary to be considered a genuine pain syndrome.18
It is important for people who
suffer from pain with symptoms
similar to those of dentin hypersensitivity to consult a dentist, because
dentin hypersensitivity may share
similar symptoms with dental caries
and advanced periodontal diseases.
In addition, the cause of the pain
should be identified and a diagnosis
by exclusion must be made for
dentin hypersensitivity, ruling out
other conditions requiring different
treatment. Once the diagnosis of
dentin hypersensitivity is confirmed, the dentist often needs to
discuss the patient’s oral hygiene
habits and diets. Precautions and
actions may need to be taken by
both patient and dentist. A list of
preventive recommendations is
shown in Table 1.19
Tooth sensitivity is to be expected
following dental whitening treatments, independent of technique
and products used.20 A clinical trial
compared various methods of external teeth bleaching and found that
tooth sensitivity is more common
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Dentinal Hypersensitivity & treatment Dentin hypersensitivity and its management
Chart 1. Algorithm for diagnosis and management of dentin hypersensitivity. (Canadian Advisory Board
on Dentin Hypersensitivity. Consensus-based recommendations for the diagnosis and management of
dentin hypersensitivity. J Can Dent Assoc 2003;69(4):221-226. Reprinted with permission.)
SCREEN PATIENT: Does your patient suffer from twinges or stabs of pain or sensitivity?
NO
No treatment required
YES
OBTAIN PATIENT HISTORY
• Probeforintrinsicandextrinsicacids
• Askpatienttodescribepain(lookfor • Obtaindetaileddietaryhistory(look
description of pain as short, sharp)
for excessive dietary acids: e.g.,
• Askpatienttoidentifypain-inciting
citrus juices and fruits, carbonated
stimuli (look for thermal, tactile,
drinks, wines, ciders)
evaporative, osmotic, chemical)
• Probeforgastricacidrefluxand
• Determinepatient’sdesirefor
excessive vomiting
treatment
Is your patient’s examination/history consistent with dentin hypersensitivity? b
EXAMINE PATIENT TO EXCLUDE a
• Crackedtoothsyndrome
• Post-restorativesensitivity
• Fracturedrestorations
• Marginalleakage
• Chippedteeth
• Pulpitis
• Dentalcaries
• Palatogingivalgrooves
• Gingivalinflammation
NO
Diagnosis inconsistent with dentin hypersensitivity
Seek other causes
YES
Treat other causes
CONFIRM YOUR PATIENT’S DIAGNOSIS c
INITIATE MANAGEMENT FOR DENTIN HYPERSENSITIVITY
• Educatepatienttoremoveriskfactors
• Recommendremovalofexcessivedietaryacids
• Recommendtoothbrushingremotefrommealtime(preferablybefore)
• Adviseagainstoverlyfrequentoraggressivetoothbrushing/hygiene
FOLLOW-UP: Does your patient’s dentin hypersensitivity persist?
NO
No further treatment
YES
INITIATE TREATMENT FOR DENTIN HYPERSENSITIVITY
Applydesensitizingtechniqueswithconsiderationforconvenienceandcost-effectiveness
NONINVASIVE
• Desensitizingtoothpasteusedcorrectlyd
• Topicalagents
INVASIVE
• Mucogingival
surgery
FOLLOW-UP: Does your patient’s dentin hypersensitivity still persist
(i.e., does your patient report improvement but still have pain and,
if so, does your patient still desire further treatment?)?
• Resins
• Pulpectomy
Maintain current therapy
long-term and review
regularly. Reconsider
predisposing factors.
NO
YES
No further treatment
REVIEW DIAGNOSIS TO EXCLUDE
• Periodontalpain
• Neuropathicpain
• Referredpain
• Chronicpainsyndrome
Should you continue dentin hypersensitivity treatment and patient education?
YES
Continue dentin hypersensitivity treatment and patient education,
with ongoing reminders to alter predisposing factors
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NO
Refer patient
to appropriate
specialist
(dental or
medical)
a. Potentially useful
diagnostic tools
• Airjet
• Coldwaterjet
• Otherthermaltests
• Dentalexplorer
• Periodontalprobe
• Radiographs(ifneeded)
• Percussiontesting
• Assessmentofocclusion
• Bitestresstests
b. Definition of dentin
hypersensitivity
Dentin hypersensitivity
ischaracterizedbyshort,
sharp pain arising from
exposed dentin in response
to stimuli (typically thermal,
evaporative, tactile,
osmotic, or chemical) and
which cannot be ascribed
to any other form of dental
defect or disease.
c. Other potential
diagnostic aids
• Selectiveanesthesia
• Transillumination
d. The best results are
achievedifdesensitizing
toothpaste is applied via
twice-daily brushing,
performed on an ongoing
basis according to a regular
schedule (not applied
topically, as in “dabbing”).
and in greater sensitivity with inoffice, chemical-activated or lightactivated 35% hydrogen peroxide
solution.20 Therefore, dentists could
consider recommending at-home
bleaching with a low concentration
of peroxide, such as custom-formed
trays with 10% carbamide peroxide or 3.5% hydrogen peroxide;
another option is a 6% carbamide
peroxide varnish. It is essential to
inform patients that all whitening
procedures can cause hypersensitivity, although it does not always
occur. Since the mechanism of
tooth sensitivity after external tooth
bleaching is unknown, management
is mainly supportive. The use of
analgesics may help to reduce tooth
sensitivity. A clinical trial found that
a single 600 mg dose of ibuprofen
administered orally reduced tooth
sensitivity during, but not after, the
treatment period.14
Dietary changes and behavior
modifications, such as decreasing the intake of acid-containing
foods or carbonated drinks, often
are necessary to manage dentin
hypersensitivity. The patient also
should be shown correct brushing techniques, because improper
toothbrushing has often been closely
correlated to dentin hypersensitivity.
It has been shown that manual and
power toothbrushes used with a
desensitizing toothpaste are almost
equally effective in reducing dentin
hypersensitivity symptoms.21 A
systematic, structured approach
to the problem of dentin hypersensitivity has been developed and
incorporated into an easy-reference
algorithm for diagnosis and management by the CABDH (Chart 1).17
Home management with
desensitizing toothpastes
Using a desensitizing toothpaste
is considered by many as the
“first option” in relieving dentin
Fig. 6. Interruption of the neural response to
pain stimuli with potassium ions.
Fig. 7. Occlusion of the open tubules to prevent
pain stimuli.
hypersensitivity. This treatment
is effective, but it often takes four
to eight weeks for pain relief.
Desensitizing toothpastes provide
relief from dentin hypersensitivity
symptoms in two ways: First, they
interrupt the neural response to
pain stimuli by the penetration
of potassium ions through the
tubules to the A-fibers of the nerves,
thereby decreasing the excitability of
these nerves (Fig. 6). Second, they
occlude open tubules to block the
hydrodynamic mechanism (Fig. 7).
Desensitizing toothpastes such
as Sensodyne (GlaxoSmithKline),
Colgate Sensitive (ColgatePalmolive), and Elmex Sensitive
(GABA International AG) contain
potassium salts, strontium salts,
and/or fluoride compounds. These
compounds use different approaches
to produce the desensitizing effect.
Potassium salts, such as potassium
nitrate and potassium chloride, provide potassium ions to decrease the
excitability of nerves that transmit
pain sensation. Strontium salts, such
as strontium chloride and strontium
acetate, form mineralized deposits
within porous dentinal tubules and
create a barrier on the surface of
the exposed dentin. Fluoride compounds, such as sodium fluoride
and amine fluoride, form precipitation of insoluble metal compounds,
mainly calcium fluoride globules,
that promote remineralization and
occlude dentinal tubule openings on
the exposed dentin surface.
Desensitizing toothpastes with
new chemicals, such as amorphous
calcium phosphate and casein
phosphopeptide-amorphous
calcium phosphate (ACP-CPP)
and arginine-calcium carbonate
(arginine-CaCO3) and calcium
sodium phosphosilicate (CSPS) bioactive glass, are now available commercially. The arginine-CaCO3 and
ACP-CPP products have a similar
mechanism of action to occlude and
block open dentinal tubules from
external stimuli associated with
dentin hypersensitivity.
When combined with water, ACP
crystallizes on the teeth in the form
of new enamel. CPP stabilizes ACP
until it is applied to teeth. CPP also
helps bind ACP to plaque, bacteria,
soft tissue, and dentin, where ACP
is slowly released to form enamel.
MI Paste (GC America Inc.) contains ACP-CPP, while MI Paste Plus
incorporates 0.2% sodium fluoride
(900 ppm fluoride). In 2008, Reynolds et al reported that a dentifrice
containing 2% CPP-ACP plus
1,100 ppm fluoride was superior to
an ACP-CPP dentifrice in arresting
caries progression and remineralizing enamel subsurface lesions.22
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Dentinal Hypersensitivity & treatment Dentin hypersensitivity and its management
A new toothpaste containing
arginine-CaCO3 (Pro-Relief, Colgate-Palmolive) was introduced in
2009. Arginine is a naturally occurring amino acid that is combined
with CaCO3 to form a deposit that
seals open dentinal tubules. A recent
clinical trial demonstrated that
brushing with a toothpaste containing 8% arginine-CaCO3 is effective
in reducing dentin hypersensitivity.23
CSPS bioactive glasses (NovaMin,
GlaxoSmithKline) are known to
induce osteogenesis in physiological systems and have been shown
to be able to seal and clog open
dentinal tubules.24 When NovaMin
particles come in contact with saliva
and water, they react by releasing
calcium and phosphate ions to seal
open dentinal tubules. SootheRx
(3M ESPE), a toothpaste containing
NovaMin, has been shown to reduce
dentin hypersensitivity.25
In-office professional care
In addition to asking patients to
use desensitizing toothpastes at
home, dentists can apply a variety
of professional products to exposed
dentin surfaces to reduce dentin
hypersensitivity. These products
include resin-based materials,
glutaraldehyde, hydroxyethylmethacrylate (HEMA), potassium
oxalates, sodium fluoride varnish,
and silver diamine fluoride (SDF)
solution. These products generally
occlude and seal exposed dentinal
tubules. Some dentin bonding
agents, such as Clearfil New Bond
(Kuraray Dental) and Xeno III
(Dentsply International), have demonstrated success in sealing dentinal
tubules to treat and prevent sensitivity without an etching agent. A
dentin bonding agent that requires
an acidic agent opens the pathway
for the diffusion of monomers into
the collagen network, but it also
facilitates the outward seepage of
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March/April 2011
tubular fluid from the pulp to the
dentin surface. This process deteriorates bonding for some of the
current adhesives.26
An aqueous solution of glutaraldehyde and HEMA, such as Gluma
Desensitizer (Heraeus Kulzer Inc.)
or Calm-It (Dentsply Caulk), has
been used as a desensitizing agent,
with glutaraldehyde serving as the
mechanism for tubule occlusion.27
Some dentists use potassium oxalate
to precipitate and occlude dentinal
tubules to treat dentin hypersensitivity. Super Seal (Phoenix Dental) is a
potassium oxalate-based, acid-resistant desensitizer that can be applied
with a cotton pellet for root sensitivity after periodontal treatment.
Fluoride can be incorporated
incrementally into fluorapatite crystals on the tooth surface, making
the surface more resistant to acid
dissolution. Fluoride also enhances
enamel remineralization, increasing
the speed of remineralization and
also increasing the mineral content
of exposed dentin.28 Fluoride
varnish is a popular agent used by
dentists because it can be applied
quickly and easily. Furthermore,
it sets rapidly on tooth surfaces so
that gagging and swallowing are
minimized. Due to their simplicity
in clinical use, fluoride varnishes
containing 5% sodium fluoride,
such as Duraphat (ColgatePalmolive), Duraflor (Medicom),
and Fluorilaq (Pascal International,
Inc.), are becoming more popular
for treating dentin hypersensitivity.
An extended-contact varnish
(Vanish XT, 3M ESPE) is a photocured fluoride varnish that forms
an immediate layer of protection
to relieve dentin hypersensitivity.
This varnish is a resin-modified
glass ionomer that contains
glycerophosphate for calcium and
phosphate release in addition to
fluoride. The formation of resin
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tags provides an immediate and
extended period of occlusion of the
dentinal tubules.
SDF is another emerging fluoride
agent. Recent reviews conclude that
SDF not only desensitizes dentin,
it also arrests caries progression.29,30
Saforide (Toyo Seiyaku Kasei Co.,
Ltd.) contains 38% SDF, or approximately 44,800 ppm of fluoride
ion. It is a colorless solution widely
used in countries such as Australia,
China, and Japan. A transient
mucosal irritation may develop after
topical application, but no serious
complications were reported. However, SDF is currently unavailable in
the United States.
Iontophoresis, a technique that
utilizes a low galvanic current to
accelerate ionic exchanges and precipitation of insoluble calcium with
fluoride gels, has also been used to
occlude open dentinal tubules.31
Dention (Pikosystem Co., Ltd.)
is a portable iontophoresis device
that uses four alkaline batteries to
deliver sodium fluoride gel using a
spoon tray with a low electric current to minimize dentin hypersensitivity. Two or three four-minute
treatments generally are required
to eliminate or reduce the dentin
hypersensitivity for a period of two
to six months.
Arginine-CaCO3 also is used as
an active ingredient in a professionally used prophy paste to manage
dentin hypersensitivity. A clinical
study of 390 patients indicated that
professional prophylaxis by dentists
and dental hygienists using an
arginine-CaCO3 paste could reduce
dentin hypersensitivity significantly.32 Furthermore, dentists can
apply a dental sealant and cavity
varnish to cover the exposed dentin
surface. In conditions where enamel
and/or dentin have been lost due
to abrasion, erosion, and/or abfraction, leaving a notching of the root,
filling materials such as glass ionomer and composite resin can cover
the exposed root and restore tooth
morphology.
In addition to topical application
of various products, other clinical treatment methods have been
used. One option is to use lasers,
either alone or in combination with
surface treatments such as topical
fluoride application, to manage
dentin hypersensitivity.33 Gingival
grafts are another option, particularly when gingival recession is
progressive, when there are esthetic
concerns, or if dentin hypersensitivity is unresponsive to more conservative treatments. A clinical study
of 11 cases reported success with a
two-stage surgical technique.34
Conclusion
Although dentin hypersensitivity is
a common oral health problem for
many adult population groups, highquality scientific studies on the epidemiology, biologic mechanism, and
treatment of this condition are lacking. Many treatment methods have
been proposed, yet no universally
accepted or highly reliable desensitizing agent or treatment has been identified. Well-conducted clinical trials
are needed to provide high-quality,
evidence-based outcomes to guide
clinicians and patients in choosing
the most appropriate treatment for
dentin hypersensitivity.
When a patient has symptoms
that can be attributed to dentin
hypersensitivity, the dentist should
perform a thorough clinical examination to rule out the other likely
causes prior to diagnosis and treatment. Depending on the identified
cause, a combination of individualized instructions on proper oral
health behaviors, use of at-home
products, and professional treatment may be required to manage
the problem.
Disclaimer
The authors have no financial,
economic, commercial, and/or
professional interests in any of the
products or manufacturers listed in
this article.
Author information
Dr. Chu is an associate professor
and Dr. Lo is a professor in the
faculty of dentistry, University of
Hong Kong. Ms. Lam is an associate professor in dental hygiene, City
University of New York.
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2. Irwin CR, McCusker P. Prevalence of dentine
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4. Smith WA, Marchan S, Rafeek RN. The prevalence and severity of non-carious cervical lesions in a group of patients attending a
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7. Chabanski MB, Gillam DG, Bulman JS, Newman
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9. Gillam DG, Seo HS, Bulman JS, Newman HN.
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10. Chu CH, Pang KL, Yip HK. Dietary behaviour and
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11. Addy M. Dentine hypersensitivity: Definition,
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Tooth wear and sensitivity: Clinical advances in
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2000:239-248.
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12. Academy of General Dentistry. AGD public
awareness campaign: Dentin hypersensitivity.
AGD Impact 2010;38(2):6-7.
13. Absi EG, Addy M, Adams D. Dentine hypersensitivity: A study of the patency of dentinal tubules
in sensitive and non-sensitive cervical dentine. J
Clin Periodontol 1987;14(5):280-284.
14. Charakorn P, Cabanilla LL, Wagner WC, Foong
WC, Shaheen J, Pregitzer R, Schneider D. The
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15. Marshall K, Berry TG, Woolum J. Tooth whitening: Current status. Compend Contin Educ Dent
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16. Brannstrom M. A hydrodynamic mechanism in
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through the dentine. In: Anderson DJ, ed. Sensory mechanisms in dentine. Oxford: Pergamon
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17. Canadian Advisory Board on Dentin Hypersensitivity. Consensus-based recommendations for
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18. Curro FA. Tooth hypersensitivity in the spectrum
of pain. Dent Clin North Am 1990;34(3):429-437.
19. Drisko CH. Dentine hypersensitivity—Dental
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20. Amengual J, Forner L. Dentine hypersensitivity in
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2009;58(4):181-185.
21. Sengupta K, Lawrence HP, Limeback H. Comparison of power and manual toothbrushes in dentine sensitivity. J Dent Res 2005;84(spec issue
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22. Reynolds EC, Cai F, Cochrane NJ, Shen P, Walker
GD, Morgan MV, Reynolds C. Fluoride and casein phosphopeptide-amorphous calcium phosphate. J Dent Res 2008;87(4):344-348.
23. Ayad F, Ayad N, Delgado E, Zhang YP, DeVizio W,
Cummins D, Mateo LR. Comparing the efficacy
in providing instant relief of dentin hypersensitivity of a new toothpaste containing 8.0% arginine, calcium carbonate, and 1450 ppm
fluoride to a benchmark desensitizing toothpaste containing 2% potassium ion and 1450
ppm fluoride, and to a control toothpaste with
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Mississauga, Canada. J Clin Dent 2009;20(4):
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The effects of a novel bioglass dentifrice on
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35-39.
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diamine fluoride: A caries “silver-fluoride bullet.” J Dent Res 2009;88(2):116-125.
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with hypersensitivity. J Dent Res 2010;89 (spec
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hypersensitive dentine. J Clin Periodontol
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34. Fombellida Cortazar F, Sanz Dominguez JR, Keogh TP, Cuerda Pilarte M, Martos Molino F. A
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Manufacturers
Colgate-Palmolive, New York, NY
800.763.0246, www.colgate.com
Dentsply Caulk, Milford, DE
800.523.2855, www.caulk.com
Dentsply International, York, PA
800.877.0020, www.dentsply.com
GABA International AG, Therwil, Switzerland
41.61.415.6060, www.gaba.com
GC America Inc., Alsip, IL
800.323.7063, www.gcamerica.com
GlaxoSmithKline, Research Triangle Park, NC
888.825.5249, www.gsk.com
Heraeus Kulzer Inc., South Bend, IN
800.431.1785, www.heraeus-dental-us.com
Kuraray Dental, New York, NY
800.879.1676, www.kuraraydental.com
Medicom, Tonawanda, NY
800.361.2862, www.medicom.com
Pascal International, Inc., Bellevue, WA
800.426.8051, www.pascaldental.com
Phoenix Dental, Fenton, MI
877.463.9905, www.phoenixdental.com
Pikosystem Co., Ltd., Godollo, Hungary
36.30.630.3571, www.pikosystem.hu
Toyo Seiyaku Kasei Co., Ltd., Osaka, Japan
www.toyo-hachi.co.jp
3M ESPE, St. Paul, MN
888.364.3577, www.3m.com
COMMENT
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March/April 2011
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self CDE
2 HOURS instruction
CREDIT
Exercise No. 280
Dentinal Hypersensitivity & Treatment
Subject Code 161
The 15 questions for this exercise are based on the article
“Dentin hypersensitivity and its management” on pages
115-122. This exercise was developed by Gus E. Gates,
DDS, MAGD, in association with the General Dentistry
Self-Instruction committee.
5.
Which teeth are most commonly affected by
dentin hypersensitivity?
A. Incisors and canines
B. Molars and premolars
C. Premolars and incisors
D. Canines and molars
Reading the article and successfully completing the
exercise will enable you to:
• define dentin hypersensitivity and give its etiology;
• describe the prevalence of dentin hypersensitivity; and
• discuss methods and materials for the treatment of
dentin hypersensitivity.
6.
Dentin hypersensitivity usually occurs in patients in
which age bracket?
A. 20–29
B. 30–39
C. 40–49
D. 50–59
7.
Within the dentinal tubules, the unmyelinated
nerve fibers (C-fibers) are responsible for the
sensation of dentin hypersensitivity. The number
of open dentinal tubules per surface area in teeth
with dentin hypersensitivity is eight times that of
non-hypersensitive teeth.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
8.
Tooth erosion and dentin hypersensitivity can
be caused by frequent consumption of all the
beverages listed below except:
A. Lemon tea
B. Orange juice
C. Diet cola
D. Coffee
9.
According to a 2009 Academy of General Dentistry
survey, what is the most common strategy for
dentists to manage dentin hypersensitivity?
A. Using topical fluoride
B. Improving tooth brushing
C. Applying sealant material
D. Changing patient drinking habits
1.
Dentin hypersensitivity can be defined as a
________ duration, _______ pain arising from
exposed dentin.
A. long, sharp
B. short, sharp
C. short, dull
D. long, dull
2.
Less than 20% of periodontal patients have
problems with dentin hypersensitivity. This is
because patients with periodontal disease are at a
lower risk for dentin hypersensitivity.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
3.
4.
Dentin hypersensitivity is a problem that does not
significantly affect a patient’s quality of life. For
this reason, most patients do not seek treatment
for it.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
According to patients, what is the most common
initiating factor for dentinal hypersensitivity?
A. Sour food
B. Hot drinks
C. Cold drinks
D. Sweet food
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123
10.
11.
12.
Suggestions to patients for preventing dentin
hypersensitivity include all of the following except:
A. Avoid medium or hard toothbrushes
B. Avoid brushing teeth immediately after
ingesting hot foods
C. Avoid using large amounts of dentifrice
during brushing
D. Avoid excessive flossing
13.
Which of the following is not found in a
desensititizing toothpaste?
A. Potassium salts
B. Strontium salts
C. Fluoride compounds
D. Magnesium
14.
Suggestions for dental professionals to prevent
dentin hypersensitivity include all of the following
except:
A. Avoid the use of all home bleaching products
B. Avoid overpolishing exposed dentin
C. Avoid violating the biological width during
restoration placement
D. Avoid overinstrumenting the root surface
during scaling
Fluoride compounds decrease the excitability
of the nerves to stimuli by forming mineralized
deposits with the porous dentinal tubules. This
creates a barrier on the surface of the exposed
dentin.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
15.
Which chemical has been shown to form new
enamel on teeth?
A. Amorphous calcium phosphate
B. Casein phosphopeptide
C. Calcium carbonate
D. Calcium sodium phosphosilicate
A clinical trial compared various methods of
external tooth bleaching and found that tooth
sensitivity is more common with in-office systems
that contain _____% of hydrogen peroxide.
A. 20
B. 25
C. 30
D. 35
Answer form and Instructions are on pages 159-160.
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Dental Materials
CDE
2 HOURS
CREDIT
Diametral tensile strength of composite core
material with cured and uncured fiber posts
Sheila Pestana Passos, MDS Maria Jacinta M.C. Santos, DDS, MSc, PhD
AminS.Rizkalla,PhD,P.Eng. Gildo Coelho Santos Jr., DDS, MSc, PhD
n
n
Omar El-Mowafy, BDS, PhD
n
The aim of this study was to determine the influence of different
types of posts and post head designs on the fracture resistance
of a composite resin core material using the diametral tensile
strength (DTS). Seventy-five disc specimens were prepared using
a composite core and prefabricated glass fiber posts and were
divided into four test groups and one control group ( n = 15).
F
iber posts are used extensively
to restore endodontically
treated teeth because they present some potential advantages over
metal posts, such as a modulus of
elasticity similar to that of dentin,
high tensile strengths compatible
with Bis-GMA bonding procedures, esthetics, and easy handling
characteristics.1-3 Prefabricated
fiber-reinforced composite (FRC)
posts are used to provide retention
to a composite resin core buildup
when the coronal tooth exhibits an
extensive loss. Prefabricated FRC
posts have been used as a possible
substitute for cast post and core restorations of endondontically treated
teeth.4,5 According to the predominant view, the post and core should
be used to increase the retention of
fixed prosthetic reconstruction, not
for reinforcement.6
Several post designs and surface
characteristics are used to increase
retention and to optimize stress
distribution on the root; for this
reason, the post head design is
an important factor in creating
a reliable substructure for a core
restoration.7 Post heads can be flat,
spherical, or serrated; the most
commonly used core materials are
The use of fiber posts reduced the DTS of the composite core
material; the DTS value of the control material was significantly
higher ( p = 0.05) than all of the test groups.
Received: May 26, 2010
Accepted: June 21, 2010
amalgam, composite, and glass-ionomer cement.8 In some situations,
the clinician faces the challenge of
shortening the post when it is too
long compared to the preparation
inside the root. Cutting the fiber
post at its apical portion may lead to
a post that is shorter than expected
and requires replacement. On the
other hand, cutting the post head
after cementation avoids the risk of
the post being too short; however,
if the post has a specially designed
head, this feature is removed and the
extra retention could be lost.
Retention values provide a rapid
and convenient way of comparing post stability. Core buildup
materials with greater retention are
more resistant to dislodgement,
which occurs due to lateral occlusal
stresses.9 The failure rate of crowns
placed over fiber post and cores has
been measured to be 8%; the major
cause of failure was interfacial failure
between post and core materials.7-11
The interaction between composite
resins and fiber-reinforced posts is
critical for the success of restorations
placed over these materials. The
experimental and manufacturer’s
surface treatments as well as the
adhesive application have enhanced
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the bond strength between fiber
posts and resin cement.12
In FRC post technology, glass
or quartz fibers are coated with a
silane coupling agent to improve
the adhesion at the fiber-resin
matrix interface, protect fibers
from damage during handling,
modify the catalytic and wettability
properties of fiber surfaces, and
increase the chemical durability of
the fiber-matrix interface, especially
to water.12 However, the silane
coupling agent is able to chemically
bridge only resins and hydroxidecovered inorganic substrates.13
Moreover, a chemical bond is possible only between the composite
resin core material and the exposed
fibers of the post at the fiber post/
composite core interface.
The highly cross-linked polymers
of the matrix in FRC posts do not
have any functional groups available
for reaction.13,14 In FRC materials such as EverStick (StickTech),
an effort to solve the problem of
adhering to highly cross-linked
polymers has been made by
utilizing semi-interpenetrating
polymer network (IPN) structures.14 With this technology, the
fibers are pre-impregnated with a
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125
Dental Materials Diametral tensile strength of composite core material with cured and uncured fiber posts
Table 1. Core materials used in this study.
Group
Core material
Manufacturer
Lot No.
1 (control)
ParaCore
Coltene/Whaledent
0095236
2
EverStick (conventional)
Stick Tech Ltd.
2050426-ES-125
3
ParaPost (without head)
Coltene/Whaledent
MT-52625
4
ParaPost (conventional)
Coltene/Whaledent
MT-52625
5
EverStick (separated head)
Stick Tech Ltd.
2050426-ES-125
Fig. 1. Posts centered in core buildup material.
difference in DTS of the composite
resin core material with or without
conventional or modified posts with
or without a head.
Chart 1. Average (±SD) DTS values (MPa) and Tukey’s B
rank order test results. A solid line indicates values that
present no significant difference (p = 0.05).
45
Materials and methods
40
DTS (MPa ± SD)
35
30
25
20
15
10
5
0
1
2
polymethylmethacrylate (PMMA),
which may be partially dissolved by
the application of a photocuring
resin for five minutes. As a result
of the partial dissolution at the
surface of the fiber frame, grooves
and undercuts are created where
micromechanical bonding can
be established in addition to the
chemical adhesion. According to
the manufacturer, the post surface
is thereby “reactivated” to offer
considerably more favorable conditions for adhesion to the core or the
luting material.15
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March/April 2011
3
Group
4
5
Little information is available in
the literature about the alteration of
the design of ParaPost or EverStick
posts within composite core material. Therefore, the objective of this
study was to evaluate the diametral
tensile strength (DTS) when cured
glass fiber posts (ParaPost) and
uncured glass fiber posts (EverStick)
with different designs are bonded
to ParaCore core buildup material.
This study had two null hypotheses:
There is no difference in DTS of the
composite resin core material with
or without a post; and there is no
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Seventy-five disc-shaped specimens
6.0 mm in diameter and 3.0 mm
thick (n = 15) were produced using
a stainless steel jig.11 The posts
were incorporated at the centers of
the composite resin core material
(Fig. 1); the composite core materials are shown in Table 1.
Composite resin discs with no
posts were prepared as a control
group (Group 1). For Group 2,
a conventional EverStick post
was used. Group 3 used ParaPost
Fiber Lux (Coltene/Whaledent)
after removing the head portion;
the ParaPost surfaces were coated
with a non-rinse conditioner
(ParaBond, Coltene/Whaledent),
as suggested by the manufacturer.
One drop from each of two adhesives (ParaBond Adhesive A and
ParaBond Adhesive B, Coltene/
Whaledent) was mixed, applied to
the post surface, and air-dried for
five seconds. In Group 4, ParaPost
Fiber Lux was used with the head
intact; specimens were prepared as
described for Group 3. In Group
5, an EverStick post with a modified end was used. The fibers at the
post end were spread apart to allow
the composite material to flow in
between prior to polymerization.
Each specimen was photopolymerized (QHL75, model 506, Dentsply
International, output: 600 mW/
cm2) for 120 seconds. Specimens
were stored in distilled water at
37°C for seven days prior to the
mechanical test.
For DTS testing, compressive
loading was subjected perpendicular
to the circumferential area of the
disc specimen using a universal testing machine (Instron Model 8501;
Instron Corp.) at 0.5 mm/min
crosshead speed. Load was applied
until failure occurred. DTS values
were calculated using the formula
described below:
σx=
2p
πDT
where σx is the DTS (MPa), p is the
force (N), D is the specimen diameter (mm), and T is the specimen
thickness (mm).16 Means and standard deviations (SD) were calculated
and data were statistically analyzed
using one-way ANOVA and Tukey’s
B-rank order tests at p = 0.05.
Results
A comparison of DTS values for all
groups tested is shown in Chart 1.
The DTS values were separated
into three groups at p < 0.05. These
values ranged from 25.72 MPa for
Group 5 to 41.07 MPa for Group 1.
Tukey’s test revealed that the control
group exhibited significantly higher
DTS values than all of the other
materials tested (p < 0.05). Groups
2 and 3 exhibited DTS values that
were 27–31% lower than that of the
control group, while the DTS values
of Groups 4 and 5 were 37% lower
than that of the control group. In
addition, the mean DTS values for
Group 2 were significantly higher
than those for Groups 4 and 5
(p < 0.05). No significant difference
was found between the DTS of
ParaPost with a head (Group 4) and
ParaPost without a head (Group 3)
(p > 0.05).
Discussion
DTS is an alternative to direct tensile testing suitable for brittle materials; the main advantages of this test
are its relative simplicity and the
reproducibility of the results. For the
DTS test, a disc of the brittle material is compressed along the radial
direction until fracture occurs, at
which point the compressive stress
applied to the specimen introduces
a tensile stress in the material in the
plane of the force being applied by
the test machine.16
In the present study, the first
hypothesis was not validated, as
the composite resin core material
without a post showed higher
DTS than the composite resin core
material with a post. The second
hypothesis was partially accepted,
in that no difference in DTS was
observed between ParaPost with a
head and ParaPost without a head,
while the conventional EverStick
post presented higher DTS than the
modified EverStick post.
The design of the post and core
specimens in the present study represented a clinical scenario in which
there is limited interocclusal height.
Clinically, when a core material is
added to the post, it should extend
approximately 2.0 mm above the
post head; however, some clinical
situations do not allow such extension and the post head is finished
flush with the core’s top surface.11,16
If the specimens in this study had
allowed the post to extend to only
half the thickness of the core, simulating an ideal clinical situation
of 2.0 mm of core above the post
head, higher DTS values may have
been recorded.11
In the present study, modification
of the ParaPost (Groups 3 and 4)
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did not present a significant difference in DTS values, indicating
that the ParaPost head is ineffective
in increasing retention of the core
buildup material to the post when
compressive forces are applied. The
clinical implication of this finding
is that the ParaPost head can be cut
off prior to or after cementation
when a shorter post is required at
both ends (head or apical), without
compromising the retention of the
core buildup material. These results
are consistent with those from a
previous study.11 In addition, modification of the EverStick post design
resulted in significantly lower DTS
values compared to the conventional
EverStick post, indicating that separation of EverStick fibers weakens
the entire specimen in tension.
The control group, consisting of
ParaCore buildup material only
with no posts, exhibited the highest
DTS values (41.07 MPa) of all of
the groups. A range of DTS values
from 32–52 MPa for six photopolymerized composite resins has been
reported previously.17 Incorporation
of posts in the core specimens
resulted in a significant reduction
in the DTS values of the specimens,
regardless of the type of post used.
These findings demonstrate that
the composite resin core material
provides higher fracture resistance
when used as a solid block. The
clinical significance of this finding needs to be further explored;
additionally, posts with other head
designs should be tested.
Conclusion
Within the limitations of this study,
it can be concluded that the inclusion of posts weakens composite
resin cores in tension; there was
no difference in DTS between the
cured ParaPost and the uncured
EverStick post. Also, the ParaPost
head appears to be ineffective in
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127
Dental Materials Diametral tensile strength of composite core material with cured and uncured fiber posts
increasing retention of the post to
the core material; therefore, the
post head can be cut off in order to
achieve the desired post length.
Acknowledgements
The authors would like to thank
StickTech Ltd. and Coltene/
Whaledent for providing sample
materials for this research.
Disclaimer
The authors have no commercial
relationship with any of the manufacturers listed in this article.
Author information
Dr. Passos is a postgraduate
student, Department of Dental
Materials and Prosthodontics, Sao
Jose dos Campos Dental School,
Sao Paulo State University, Sao
Jose dos Campos, SP, Brazil. Drs.
Maria Santos and Gildo Santos Jr.
are assistant professors, Division
of Restorative Dentistry, Schulich
School of Medicine and Dentistry,
University of Western Ontario,
London, ON, Canada, where Dr.
Rizkalla is an associate professor,
Division of Biomaterials Science.
Dr. El-Mowafy is a professor,
Clinical Sciences/Restorative
Dentistry, Faculty of Dentistry,
University of Toronto, ON,
Canada.
11.
References
1. Asmussen E, Peutzfeldt A, Heitmann T. Stiffness, elastic limit, and strength of newer types
of endodontic posts. J Dent 1999;27(4):275278.
2. Mannocci F, Innocenti M, Ferrari M, Watson TF.
Confocal and scanning electron microscopic
study of teeth restored with fiber posts, metal
posts, and composite resins. J Endod 1999;
25(12):789-794.
3. Purton D, Chandler N, Qualtrough A. Effect of
thermocycling on the retention of glass fiber
root canal posts. Quintessence Int 2003;34(5):
366-369.
4. Matinlinna JP, Lassila LV, Ozcan M, Yli-Urpo A,
Vallittu PK. An introduction to silanes and their
clinical applications in dentistry. Int J Prosthodont 2004;17(2):155-164.
5. Silva NR, Castro CG, Santos-Filho PC, Silva GR,
Campos RE, Soares PV, Soares CJ. Influence of
different post design and composition on stress
distribution in maxillary central incisor: Finite
element analysis. Indian J Dent Res 2009;20(2):
153-158.
6. Torbjorner A, Karlsson S, Odman PA. Survival
rate and failure characteristics for two post designs. J Prosthet Dent 1995;73(5):439-444.
7. Cohen BI, Condos S, Deutsch AS, Musikant BL.
Fracture strength of three different core materials
in combination with three different endodontic
posts. Int J Prosthodont 1994;7(2): 178-182.
8. Kahn FH, Rosenberg PA, Schulman A, Pines H.
Comparison of fatigue for three prefabricated
threaded post systems. J Prosthet Dent 1996;
75(2):148-153.
9. Cohen BI, Musikant BL, Deutsch AS. Comparison of retentive properties of four post systems.
J Prosthet Dent 1992;68(2):264-268.
10. Campos TN, Arita CK, Missaka R, Adachi LK,
Adachi EM. Influence of core materials in the
12.
13.
14.
15.
16.
17.
microleakage of cast crowns. Cienc Odontol
Bras 2005;8(4):13-17.
Santos Jr GC, El-Mowafy O, Hernique Rubo J. Diametral tensile strength of a resin composite
core with nonmetallic prefabricated posts: An in
vitro study. J Prosthet Dent 2004;91(4):335341.
Ishida H. Structural gradient in the silane coupling agent layers and its influence on the
mechanical and physical properties of composites. In: Ishida H, Kumar G, eds. Molecular characterization of composite interfaces. New York:
Plenum Press;1985:25-50.
Cecilia G, Ornella R, Francesca M, Beatrice B,
Egidio B, Marco F. The adhesion between prefabricated FRC posts and composite resin cores:
Microtensile bond strength with and without
post-silanization. Dent Mater 2005;21(5):437444.
Kallio TT, Lastumaki TM, Vallittu PK. Bonding of
a restorative and veneering composite resin to
some polymeric composites. Dent Mater 2001;
17(1):80-86.
Vakiparta TM, Yli-Urpo A, Vallittu PK. Flexural
properties of glass fiber reinforced composite
with multiphase biopolymer matrix. J Mater Sci
Mater Med 2004;15(1):7-11.
Craig R, Craig RG, Powers JM. Restorative dental materials, ed. 11. St. Louis: Elsevier;2001:
25-50.
Eldiwany M, Powers JM, George LA. Mechanical
properties of direct and post-cured composites.
Am J Dent 1993;6(5):222-224.
Manufacturers
Coltene/Whaledent, Cuyahoga Falls, OH
800.221.3046, www.coltene.com
Dentsply International, York, PA
800.877.0020, www.dentsply.com
Instron Corp., Canton, MA
800.564.8378, www.instron.com
Stick Tech Ltd., Turku, Finland
358.02.4808.2500, www.sticktech.com
COMMENT
128
March/April 2011
General Dentistry
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self CDE
2 HOURS instruction
CREDIT
Exercise No. 281
Dental Materials
Subject Code 017
The 15 questions for this exercise are based on the article
“Diametral tensile strength of composite core material
with cured and uncured fiber posts” on pages 125-128.
This exercise was developed by William U. Wax, DDS,
FAGD, in association with the General Dentistry SelfInstruction committee.
6.
Which method is used to improve adhesion
between FRC posts and the core material?
A. Self-curing resin cement
B. Polycarboxylate cement
C. PMMA impregnation
D. Exposing OH groups in the post
7.
The study showed that the use of a post increases
the strength of the core. Removing the head of
a ParaPost increases the strength of the core as
opposed to leaving the head on.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
8.
A core material should extend approximately ____
mm above the head of the post.
A. 2
B. 3
C. 4
D. 5
9.
Leaving the EverStick fibers intact provided greater
fracture resistance than separating them. In the
study, omission of a post produced the highest DTS
values.
A. Both statements are true.
B. The first statement is true; the second is false.
C. The first statement is false; the second is true.
D. Both statements are false.
10.
The ability to maintain core retention to a ParaPost
without a head allows one to
A. shorten the post to suit intraoral conditions.
B. bond directly to a posted root.
C. use amalgam as a core material.
D. use glass ionomer as a core-cementing
medium.
11.
What percentage of crowns placed over fiber post
and core buildups fail?
A. 6
B. 8
C. 10
D. 12
Reading the article and successfully completing the
exercise will make you aware of:
• the types of available posts;
• the importance of post head design; and
• the effects of a post on composite core materials.
1.
2.
3.
The modulus of elasticity of fiber posts as
compared to metal posts is similar to that of
A. enamel.
B. dentin.
C. composite resin.
D. Bis-GMA resins.
The main purpose of a post and core is to
A. retain the restoration.
B. fill in undercuts prior to prepping the tooth.
C. re-establish the vertical height of the tooth.
D. reinforce the remaining tooth structure.
Which of the following is not a post head design
mentioned in the article?
A. Flat
B. Spherical
C. Serrated
D. Ovoid
4.
Failure of a restoration placed over a fiber post
and core can be traced to failure between
A. the crown and the core.
B. the core and the dentin.
C. the post and the dentin.
D. the post and the core.
5.
What is used to improve adhesion between fibers
and the resin matrix of the post?
A. Methylmethacrylate
B. Resin cement
C. Polycarboxylate cement
D. Silane
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129
12.
The FRC post matrix does not have available
______________ with which to react.
A. wetting agents
B. fibers
C. functional groups
D. organic substrates
13.
What is used to partially dissolve the PMMA of preimpregnated fibers?
A. Silane
B. Polycarboxylate cement
C. DTS liquid
D. Photocuring resin
14.
Experiments with post head configuration are
designed to _______________ retention and
____________ stress distribution on the root.
A. increase; optimize
B. decrease; optimize
C. increase; facilitate
d. decrease; facilitate
15.
Modification of an EverStick post end was
accomplished by
A. spreading the fibers.
B. photocuring the fibers.
C. coating the post with resin.
D. shortening the post.
Answer form and Instructions are on pages 159-160.
Answers for this exercise must be received by February 29, 2012.
To enroll in Self-Instruction, click here.
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Digital Dental Photography
Incomplete cusp fractures: Early diagnosis
and communication with patients using
fiber-optic transillumination and intraoral
photography
Samer S. Alassaad, DDS
The diagnosis of incomplete cusp fractures has primarily relied on
patient symptoms, which sometimes results in late treatment approaches. The transillumination of tooth structure by a fiber-optic
light source can be considered an important adjunct tool in the
diagnosis of incomplete cusp fractures before they reach their end
stages. Furthermore, transilluminated teeth can be documented by
intraoral photography, using a two-handed technique by holding
a transillumination device and an intraoral camera simultaneously,
I
ncomplete cusp fractures are
oblique dentinal fractures that
usually originate at the internal
line angles of intracoronal preparations; they can result in complete
cuspal fracture, with or without root
involvement, if they are permitted
to progress to a natural conclusion.1
Although one study demonstrated
that complete cusp fractures of
posterior teeth are a common occurrence, with an incidence of 69.9 per
1,000 person-years, incomplete cusp
fractures are very subtle and can be
a challenge to diagnose.2,3
Cusp fractures are seen most commonly in teeth weakened by large
intracoronal restorations, where
restoration effects are thought to be
associated with a reduced amount
of dentin supporting the cusps of
restored teeth.2-5 In addition, the
risk of cusp fractures increases
with the presence of excursive
interferences and parafunctional
occlusal habits, carious lesions,
and aging.1,3,5-9 In a tooth with
healthy pulp tissue, incomplete
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March/April 2011
with the resulting images shared with the patient. This simple,
painless, and noninvasive technique can be incorporated easily
into daily practice to evaluate high-risk sites, regardless of patient
symptoms. This article reviews incomplete cusp fractures, explains
how to detect them using transillumination and intraoral photography, and addresses how to discuss the results with patients.
Received: March 16, 2010
Accepted: June 7, 2010
cusp fractures can be symptomatic
and are reported most commonly
as persistent sensitivity to cold and
chewing; however, they also can be
asymptomatic.3 Early diagnosis is
most important in the management
of incomplete fractures to limit the
propagation of the crack and subsequent microleakage, involvement of
the pulpal or periodontal tissues, or
catastrophic failure of the cusp.7,8,10
As incomplete cusp fractures
propagate along the internal line
angles of intracoronal preparations
and toward enamel, diagonal or horizontal crack lines will become more
visible near the enamel surface;
they also may be complicated by a
vertical component when the crack
crosses a buccal or a lingual groove
or a proximal marginal ridge.11
Although visual observation can
Fig. 1. Maxillary second premolar. Left: Occlusal view of cusps weakened by an intracoronal metallic
restoration. Center: Buccal view. Right: Buccal view of a transilluminated buccal cusp showing an
incomplete fracture.
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Fig. 2. Mandibular first molar. Far left: Occlusal view. Center left: Lingual view. Center right: Lingual view of a transilluminated mesiolingual cusp. An
oblique fracture warrants further investigation. Far right: Oblique fracture involving both mesiolingual and distolingual cusps viewed under the light source
of the intraoral camera.
detect what appears to be a crack or
a fracture of the tooth structure, it
may be difficult or impossible for
the clinician to differentiate it from
an insignificant craze line.12,13 When
teeth with significant fractures are
transilluminated using a fiber-optic
light source, they will show a welldefined demarcation of blocked
illumination at the fracture lines
(Fig. 1); meanwhile, structurally
sound teeth, including those with
craze lines, will transmit the light
throughout the tooth structure.9,10,12
Magnification is a key element in
the codiagnosis of incomplete cusp
fractures. While dentists can rely
on various magnification devices
to assist in their diagnosis, patients
have a clear view of incomplete
cusp fractures only with intraoral
photography, especially when
intraoral cameras with 40–50x
magnification are used. As a result,
these images can be used to clearly
communicate the conditions that
many patients have a difficult time
understanding through verbal
explanations and can satisfy their
concerns regarding the treatment
plan.14 These images also create
valuable records of the patient’s
condition prior to the start of
dental restorative procedures.14
Devices and techniques
Capturing high-quality intraoral
images of transilluminated teeth
that demonstrate incomplete cusp
fractures requires a two-handed
technique. This technique is not
difficult to master, but it requires
practice and patience. The dentist
uses one hand to hold the transillumination device and the other
hand to hold the intraoral camera
and keeps his or her eyes on the
screen. The only assistance that
may be needed from a staff member
is retraction and saliva control.
A pen-sized cordless transillumination device that emits
an intense beam of cool, white
light powered by an LED and
transmitted through a focused
glass fiber-optic element (Microlux
Transilluminator, AdDent, Inc.)
is used along with a wand-like
intraoral camera that has the ability to automatically compensate
for the intensity of incoming light
(Advance Cam intraoral camera,
TPC Advanced Technology).
The dental operating light is
turned off to reduce the other
sources of light to a minimum.
The intraoral camera is positioned
in the lingual or buccal vestibule
and stabilized so that it covers the
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lingual or buccal surfaces of the
tooth. The transillumination device
is positioned on the suspected cusp
tip and moved around the cusp
until the incomplete fracture is
well-defined on the screen, at which
point the image is captured.
Placement of the light source at
a right angle to the fracture plane
will result in the light beam being
interrupted by the fracture, thereby
illuminating only the fractured
portion while the rest of the tooth
remains dark. On the other hand, if
no crack is present, the light beam
will not be interrupted and will dissipate gradually.
Once an incomplete cusp fracture is identified, removing the
existing restoration together with
its liner and any present caries is
recommended to directly visualize
the extension of the fracture.1,8
Oblique fractures usually will be
visible at internal line angles of
the preparation. Some of these
fractures can appear lighter than
the rest of the tooth structure due
to refraction of the illuminating light of the operatory or the
intraoral camera along the fracture
line (Fig. 2). Old fractures under
metallic restorations may be accentuated due to the presence of stains
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133
Digital Dental Photography Communication with patients using transillumination and intraoral photography
Fig. 3. Maxillary second molar. Left: Lingual view of a transilluminated distolingual cusp. Right:
Intracoronal surface of a distolingual cusp. An old fracture is accentuated by the presence of a stain.
Fig. 4. Intracoronal surface of a mesiolingual cusp on a mandibular first molar. Left: The oblique
fracture is not completely visible under the light source of the intraoral camera. Right: The extension
of the oblique fracture is more visible with fiber-optic transillumination.
(Fig. 3). However, the extension
of some other fractures may be
determined only by fiber-optic light
transillumination (Fig. 4).
Discussion
A variety of transillumination
devices have been used to reveal
incomplete fractures; however,
pen-sized cordless units specifically
manufactured for this purpose are
best-suited for such a diagnostic
technique. Their light portal is easily
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March/April 2011
and closely adapted to different
sections of the tooth in different
directions. They emit adequate light
intensity to highlight fractures by
being completely interrupted at
the fracture line. They also can be
viewed directly by the eye without a
protective device.
The transillumination device can
be considered an important adjunct
tool in the diagnosis of incomplete
cusp fractures before they reach
end stages. However, a slight
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variation in the position of the
transillumination device will yield
a less-demarcated fracture line. The
presence of deep restorations and
caries also can block fiber-optic
light transmission, making the use
of fiber-optic transillumination
problematic.1 As a consequence,
other diagnostic tests such as magnification and tactile examination
should be considered.9
At the same time, evaluating the
restoration’s structural and marginal
integrity, carious lesions, occlusal
interferences, and heavy occlusal
forces is advised. If removal of the
restoration is indicated for reasons
other than incomplete cusp fractures, the transillumination device
can still be used (after complete
removal of the restoration and
caries) to detect any incomplete
fracture that might not have been
visible during the initial examination process.3
Although extraoral cameras offer
higher resolution, most wand-like
intraoral cameras are capable of
capturing images with adequate
resolution that can be magnified
and viewed on computer monitors
and printed for further documentation purposes. Intraoral cameras
also have small heads that are
easily positioned and stabilized at
the lingual or buccal side of the
transilluminated tooth to capture
images without requiring the
use of a mirror as an additional
device. Because of their ability to
automatically compensate for the
intensity of incoming light, intraoral
cameras can easily capture details
of the brightly transilluminated
fracture line and the surrounding
tooth structure when used with the
intense light emitted by the pensized cordless units.
Once an incomplete cusp
fracture is diagnosed, it should be
considered structurally unsound,
and protection from occlusal forces
to minimize fracture propagation
is indicated.1,11 Many techniques
have been described to protect teeth
with fractured cusps. Definitive
treatment has included occlusal
adjustment, pin-retained amalgams,
bonded amalgams, bonded composites, cusp overlay restorations,
and full-coverage crowns, with
excellent prognosis.6,8,10 However,
future research may indicate that
intracoronal restorations and occlusal adjustments are insufficient to
stop structural breakdown and that
more protective extracoronal coverage is indicated.11
Summary
Fiber-optic transillumination and
intraoral photography are some
of the most accessible technologies that dentists can incorporate
into their practices. When used
simultaneously, these technologies
are worth even more in terms of
diagnosis, treatment planning,
documentation, education, and
presentation of treatment to today’s
more visually focused patients.
These devices can be implemented
regularly as a part of the examination process to detect incomplete
cusp fractures and to evaluate
high-risk areas such as cusps weakened by large restorations, occlusal
trauma, and carious lesions, regardless of patient symptoms.
Author information
Dr. Alassaad is in a private practice
in Davis, California.
References
1. Ailor JE Jr. Managing incomplete tooth fractures.
J Am Dent Assoc 2000;131(8):1168-1174.
2. Bader JD, Martin JA, Shugars DA. Incidence
rates for complete cusp fracture. Community
Dent Oral Epidemiol 2001;29(5):346-353.
3. Braly BV, Maxwell EH. Potential for tooth fracture
in restorative dentistry. J Prosthet Dent 1981;
45(4):411-414.
4. Gelb MN, Barouch E, Simonsen RJ. Resistance to
cusp fracture in Class II prepared and restored
premolars. J Prosthet Dent 1986;55(2):184-185.
5. Bader JD, Shugars DA, Martin JA. Risk indicators
for posterior tooth fracture. J Am Dent Assoc
2004;135(7):883-892.
6. Ratcliff S, Becker IM, Quinn L. Type and incidence of cracks in posterior teeth. J Prosthet
Dent 2001:86(2):168-172.
7. Rosen H. Cracked tooth syndrome. J Prosthet
Dent 1982;47(1):36-43.
8. Kahler W. The cracked tooth conundrum: Terminology, classification, diagnosis, and management. Am J Dent 2008;21(5):275-282.
9. American Association of Endodontists. Cracking
the cracked tooth code: Detection and treatment
of various longitudinal tooth fractures. Chicago:
American Association of Endodontists, Summer
2008. Available at: http://www.aae.org/
uploadedFiles/Publications_and_Research/
Endodontics_Colleagues_for_Excellence_
Newsletter/ECFEsum08.pdf.
10. Agar JR, Weller RN. Occlusal adjustment for initial
treatment and prevention of the cracked tooth
syndrome. J Prosthet Dent 1988;60(2): 145-147.
11. Clark DJ, Sheets CG, Paquette JM. Definitive diagnosis of early enamel and dentin cracks based on
microscopic evaluation. J Esthet Restor Dent
2003;15(7):391-401.
12. Liewehr FR. An inexpensive device for transillumination. J Endod 2001:27(2):130-131.
13. Pitts DL, Natkin E. Diagnosis and treatment of
vertical root fractures. J Endod 1983;9(8):338346.
14. Plummer KD. Incorporating digital photography
in the dental operatory. Dimens Dent Hyg 2009;
7(9):24-26.
Disclaimer
The author has no financial,
economic, commercial, and/or
professional interests in any of
the companies whose products or
devices are included in this article.
Manufacturers
AdDent, Inc., Danbury, CT
203.778.0200, www.addent.com
TPC Advanced Technology, City of Industry, CA
800.560.8222, www.tpcdental.com
COMMENT
www.agd.org
General Dentistry
March/April 2011
135
Caries Detection and Prevention
Utility and effectiveness of computer-aided
diagnosis of dental caries
Kyle D. Tracy, DMD Bradley A. Dykstra, DDS David C. Gakenheimer, PhD JamesP.Scheetz,PhD
Stephanie Lacina William C. Scarfe, BDS, MS Allan G. Farman, BDS, PhD, DSc
n
n
n
n
n
Digital radiography has created a growing opportunity for
computer-aided diagnostic (CAD) tools. The Logicon Caries
Detector (LCD), with upgraded CAD software based on user
feedback, was re-evaluated for its effectiveness via a retrospective
clinical study.
Using the upgraded LCD software, 12 dentists (evaluators)
blindly assessed 17 radiographs taken by another (attending)
dentist, who restored 28 proximal surfaces. The attending dentist
confirmed the presence of early dentinal caries, as well as identifying 48 surfaces as caries-free or with enamel caries only subject
to noninvasive treatment. The radiographs, imported into the
software using a digital imaging and communications in medicine
(DICOM) reader, were visually assessed under typical operatory
lighting conditions, then with the aid of the software’s density
analysis tool. The effectiveness of the evaluators was gauged
by calculating two measures of performance, sensitivity and
specificity, for the detection and classification of dentinal caries.
E
arly proximal surface dental
caries can be difficult to detect,
classify in terms of depth, and
diagnose visually with radiographs.
The advent of digital radiology
alone has not changed this situation
significantly. Studies have shown
that none of the digital radiography
systems (charge coupled device/
complementary metal oxide semiconductor [CCD/CMOS] sensors
and phosphorous plates) afford
better (or, in some cases, even comparable) diagnostic capability for
proximal caries detection and classification than analog intraoral D-,
E-, and F-speed film kit.1-12 Timely
treatment is imperative to halt the
progress of caries; consequently,
methods of improving caries detection are valuable. While digital
radiography on its own does not
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March/April 2011
Sensitivity among all evaluator dentists was 30% with the initial
image; 34% with the brightness and contrast adjusted image;
39% when the image was sharpened; and 69% when the density
analysis tool was utilized. Specificity was found to be 97% with
the initial image; 95% with the brightness and contrast adjusted
image; 93% with the sharpened image; and 94% when the
density analysis tool was used.
Compared to the unaided eye, the LCD can significantly improve
dentists’ ability to detect and classify caries. Dentists may be able
to find twice as much early dentinal caries requiring restoration
(or at least aggressive noninvasive treatment) than previously,
while not unnecessarily restoring additional healthy teeth. The LCD
enables dentists to obtain more information from dental digital
radiography than is possible with the unaided eye, leading to
improved patient care.
Received: November 10, 2009
Accepted: March 10, 2010
yet provide an improved diagnostic
capability, it makes possible technological advancements that aim
to extract more information from
radiographs than the trained eye
can readily see. Software programs
such as computer-aided diagnostic
(CAD) tools might have the potential to increase early detection and
classification of dental caries and
quantitatively monitor its state over
time, demonstrating the advantages of using digital radiography
versus film.
The Logicon Caries Detector
(LCD) (Carestream Dental LLC), a
patented, FDA-approved computer
diagnostic tool, is an example of
available CAD software.13,14 This
software program has been available
since 1998 for use with the Kodak
RVG Digital Radiography System
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(formerly the Trophy RVG system)
(Carestream Dental LLC). The
clinical study conducted to support
the FDA application demonstrated
that this software could help dentists
detect 20% more cases of proximal
surface caries penetrating into the
dentin and needing restoration than
they could find with the unaided
eye.14,15 At the same time, the
software did not result in additional
surfaces being restored unnecessarily.
Based on subsequent findings
from several university laboratory
studies using extracted teeth and
feedback from dental practices
using the software in a clinical
environment, the LCD has been
upgraded to include methods for
reducing calculation failures due to
complicated tooth geometry (surface contacts and overlaps); a region
of interest (ROI) adjustment
tool that automatically computes
multiple calculations to help locate
the greatest extent of the caries; a
manual override of the ROI tool to
allow the user to easily survey the
proximal surface for variations in
the caries pattern; full-screen filters
for the display image to provide the
maximum amount of visual information without affecting the calculations; and a DICOM file reader to
allow the program to be used with
any DICOM-compatible intraoral
radiograph.16-18 (The DICOM
version of this product is not commercially available at this time.) The
purpose of the current article is to
present a retrospective clinical evaluation of the updated LCD software,
using patient treatment records.
In March 2001, the National
Institutes of Health (NIH) published a consensus statement on
diagnosis and management of dental
caries, expressing a need for advances
in radiographic methods of diagnosing noncavitated lesions and a need
for clinical studies to evaluate the
efficacy of new methods. The work
reported in this article contributes to
both of these needs as identified by
the NIH panel of nonadvocate, nonfederal experts following a number
of presentations from prominent
investigators in the field.19,20
In January 2002, an International
Consensus Workshop on Caries
Clinical Trials (ICW-CCT) was held
in Scotland; it included a presentation on modern concepts of caries
management.21 Seven linked steps
were proposed to facilitate caries
management clinically:
1. Caries detection
2. Lesion measurement
3. Lesion monitoring by
repeated measures
4. Caries activity measures
5. Diagnosis, prognosis, and
clinical decision-making
6. Interventions/treatments
7. Outcome of caries control/
management
The CAD program described in
this article contributes directly to
steps 1–3, and the results from those
steps provide important input to
steps 4–7.
CAD has become a major research
field in medical imaging and
diagnostic radiology.22 Systems are
available for applications such as
detection of breast cancers in mammograms and malignant nodules in
chest radiographs. A key to success in
the medical field has been the realization that computers by themselves
are not effective enough for automatically diagnosing diseases; rather,
CAD, which brings the doctor into
the decision loop, is more effective
than the computer alone or the
doctor alone. Radiologists use the
computer output for a “second opinion” but still make the final diagnosis
and treatment decision themselves.
The LCD has been developed for
the dental field using exactly this
approach. This article outlines how
the LCD has improved dentists’
diagnostic performance in proximal
caries detection and classification.
Materials and methods
Study protocol
Radiographs were collected by one
of the authors (BAD, referred to in
this article as the attending dentist)
during routine visits of patients to
his private practice and diagnosed
by him for interproximal caries
visually and using the LCD. The
attending dentist has had the LCD
for a number of years and is familiar
with its operation and utility in
helping to determine whether caries
is present on a surface, how deep
the caries extends, and whether the
surface needs to be restored, treated
noninvasively, or merely monitored.
After examination, the attending
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dentist developed a treatment plan
to restore those surfaces where he
diagnosed the decay had entered the
dentin and restoration was necessary. During the restoration process,
photographs were taken to document the depth of decay, based on
appearance of decalcification of the
enamel (evidenced as white material
instead of the normal, translucent
enamel material) and staining of
the dentin (brown spots). A tactile
inspection also was performed to
identify soft spots.
At the same time, the attending
dentist recorded surfaces which
were caries-free or had caries in the
enamel that required monitoring
and noninvasive treatment. This
determination was based on direct
inspection of surfaces when there
was no adjacent tooth and/or based
on his long history of periodically
seeing the same patient and taking a
series of radiographs, analyzing the
suspect surfaces with the LCD, and
tracking the results over time.
In cases where caries was present in
the enamel but the attending dentist
did not believe that restoration was
required, the patient was advised to
follow one or more of the following
instructions: improve oral hygiene
using brushing and especially flossing; change diet and minimize consumption of sweets, soft drinks, and
so forth; use a daily fluoride rinse
or daily fluoride tray treatment; and
possibly use a recalcification product
such as MI Paste (GC America Inc.).
The LCD was used during follow-up
visits to monitor the state of the
caries and to assess the effectiveness
of these noninvasive measures, with
the goal being to avoid restoring the
suspect surfaces.
Seventeen of the attending
dentist’s radiographs were selected
for this study for two reasons: They
had one or more surfaces with
confirmed dentinal decay that had
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137
Caries Detection and Prevention Utility and effectiveness of computer-aided diagnosis of dental caries
Patient
Tooth density
SURFACE
ENAMEL
DENTIN
Geometric center of the density dip
Lesion probability
1.0
Strong caries
pattern
into dentin
confirming
visual evidence
Fig. 1. Visual appearance of caries (indicated
by arrows) in initial (left) , brightness and
contrast-adjusted (center) , and sharpened
(right) images for surfaces 13D (left tooth) and
14M (right tooth).
1.0
0.0
0.0
ENAMEL
DENTIN
Restoration decision threshold
Region of interest (ROI) tool
Auto. calculates 9 locations of
v-tool apex; manual over-ride
also available
Fig. 2. The LCD density analysis, pattern recognition, and correlation with known caries database for
premolar surface 13D.
been detected visually and/or with
the LCD by the attending dentist
but was not readily obvious on the
radiograph and the surfaces had
been a challenge to detect and classify; and they included caries-free
surfaces and surfaces where decay
appeared to be in the enamel only.
These latter surfaces were tracked
by the attending dentist for several
years (2006–2009) during periodic
examinations to confirm their condition. The type of treatment (restoration or noninvasive) was decided
prior to any consideration of the
radiographs’ use in this study.
It should be noted that the
attending dentist did not experience
any false positives when performing
restorations after using the results
from the LCD; this may be due to
the fact that the LCD was only part
of his decision to restore a surface.
The patient’s age, dietary habits,
oral hygiene, and caries history
were also considered when determining treatment plans.
Hardware and software
Images were collected by the
attending dentist using the Kodak
RVG 6000 digital radiography
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March/April 2011
Patient
Tooth density
SURFACE
ENAMEL
DENTIN
Geometric center of the density dip
Lesion probability
1.0
Classic early
decay pattern
into dentin. LCD
shows deeper
lesion than visual
evidence.
1.0
0.0
0.0
ENAMEL
DENTIN
Restoration decision threshold
Region of interest (ROI) tool
Auto. calculates 9 locations of
v-tool apex; manual over-ride
also available
Fig. 3. The LCD density analysis, pattern recognition, and correlation with known caries database for
molar surface 14M.
system (Carestream Dental LLC).
The surfaces were analyzed by the
attending dentist as described above
(and later by an independent team
of evaluators as described below)
for proximal caries using the LCD
(Version 4.0 Build 55) in four dif-
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ferent modalities: visual assessment
of each surface using the initial
image; visual assessment of each
surface using the image with the
brightness and contrast adjusted;
visual assessment of each surface
using the sharpened image; and
October 2006
March 2008
January 2009
Dentin
Density
change across
the caries site
Enamel
Caries outline
on radiograph
Probability
of caries vs.
restoration
decision
threshold
(yellow line)
1
0
Enamel
Dentin
Enamel
Dentin
Fig. 5. LCD analysis of one enamel caries site during three patient visits.
October 2006
March 2008
January 2009
Caries outline
on radiograph
(none found)
Density
change across
the caries site
(none found)
Enamel
assessment of each surface with the
aid of local tooth density analysis
and caries pattern recognition. This
last modality also correlates the
results with a histological database
of known caries, producing a
probability that carious lesions
are present on the subject surface
and comparing that probability
to a decision threshold for recommending that the dentist consider
restoration of the surface (based on
a 15% false positive rate).
Examples of the first three
modalities are shown in Figure 1,
while Figures 2 and 3 demonstrate
examples of the fourth modality
for the two contact surfaces shown
in Figure 1, both of which had
dentinal caries. Figure 4 highlights
the findings of the attending
dentist when he restored these same
surfaces (photo taken with a Kodak
1000 intraoral video camera).
Figure 5 shows the LCD results
over a period of 27 months for an
Enamel
Dentin
Fig. 4. Clinical confirmation of dentinal caries
for surfaces 13D (left) and 14M (right), based
on decalcified enamel (white tooth material)
and dentin staining (brown spots).
Dentin
Probability
of caries vs.
restoration
decision
threshold
(yellow line)
1
0
Enamel
Dentin
Enamel
Dentin
Enamel
Dentin
Fig. 6. LCD analysis of one caries-free surface during three patient visits.
example surface; the attending
dentist monitored it during patient
follow-up visits due to caries in
the enamel but deemed it to not
require restoration. Figure 6 shows
the LCD results over the same
27-month period for a surface that
the attending dentist designated as
caries-free.
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Retrospective blinded
clinical trial
The 17 radiographs selected for this
study were saved in DICOM format
so that the LCD could be evaluated independently of the Kodak
Dental Imaging Software (KDIS)
that had been used with the RVG
6000 sensor to collect the images.
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139
Caries Detection and Prevention Utility and effectiveness of computer-aided diagnosis of dental caries
Table 1. Results of retrospective clinical diagnoses: Sensitivity and specificity.
Sensitivity (true positive rate)
Evaluator’s viewing modality
Mean
Standard
deviation
Initial image
30.4
15.1
95% confidence interval
Coefficient
of variation
Standard
error
Lower
Upper
0.50
4.4
21.6
39.1
Brightness and contrast-adjusted image
34.2
13.6
0.41
3.9
26.4
42.1
Sharpened image
39.3
15.8
0.41
4.6
30.2
48.4
LCD density analysis
68.8
12.1
0.17
3.5
61.8
75.7
Evaluator’s viewing modality
Mean
Standard
deviation
Coefficient
of variation
Standard
error
Initial image
96.7
5.5
0.06
1.6
Brightness and contrast-adjusted image
95.3
7.9
0.08
Sharpened image
93.1
8.6
0.09
LCD density analysis
94.1
3.8
0.04
1.1
Sensitivity (true negative rate)
95% confidence interval
Lower
Upper
93.6
99.8
2.3
90.9
99.8
2.5
88.2
97.9
92.0
96.2
All figures are percentages except coefficient of variation, which is the ratio of standard deviation to mean value.
Twenty-eight proximal surfaces in
these radiographs were restored,
and the attending dentist provided
photographic evidence of the caries
penetration into the dentin (generally showing decalcification through
the enamel and brown spots in the
dentin, as shown in Fig. 4). In addition, 48 proximal surfaces in these
radiographs had been determined
by the attending dentist to be either
caries-free or having caries in the
enamel only, which needed to be
watched and treated noninvasively.
Twelve practicing licensed dentists
from the University of Louisville
School of Dentistry served as evaluators. The evaluators viewed the set
of 17 images independently, with
no knowledge of which surfaces had
been restored by the attending dentist or which ones were designated as
caries-free or with enamel caries only.
One person (author KDT) served
the role of university study coordinator. He first trained the evaluators in
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March/April 2011
the use of the LCD (typically within
one hour) on an independent set of
radiographs not used in the study
itself, then recorded their assessment
of the subject set of 17 radiographs
during a series of sessions tailored
to each evaluator’s schedule. The
coordinator also had no knowledge
of which surfaces had been restored
and which ones were designated
as caries-free or with enamel caries
only. The images were presented to
each evaluator in a different order,
based on a randomization process.
Initially, none of the evaluators were
familiar with the LCD; also, they
had limited experience with digital
radiography because the school
clinic had not yet integrated digital
intraoral radiography.
For each radiograph, the evaluators were asked to assess all of the
proximal surfaces except for those
partially off the radiograph, those
with serious overlaps blocking the
view of the enamel region of the
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tooth, those with severe cervical
burnout, those with crowns or large
restorations already in place, and
those in which the exposure was very
poor and proper visual assessment
was not possible. A total of 159
surfaces on the 17 radiographs were
assessed by each evaluator as part of
the study. There were 28 confirmed
cases of dentinal caries on the 159
surfaces, for a prevalence of 18%.
For each surface, evaluators were
asked to classify caries depth using
the following four-point scale: 0 =
no caries present; 1 = caries less than
halfway through the enamel; 2 =
caries halfway or more through the
enamel but not into the dentin; and
3 = caries through the enamel and
touching or entering the dentin.
For each radiograph, evaluators
were asked to systematically assess
all of the surfaces with one modality before moving on to the next
modality. The study objective was
to measure the incremental value of
one modality with increased image
analysis features over the previous
simpler one, so the evaluators were
prevented from using an earlier
modality on the same image later in
the study.
The study coordinator recorded
each assessment by the evaluators.
The evaluators all used the same
computer workstation in the same
room under the same artificial
lighting conditions (representative
of a dental office without windows).
The evaluators were allowed to work
at their own pace, with no time
restrictions. The study objectives,
scope, and diagnostic protocol
were reviewed and approved by the
institutional review board (IRB)
of the University of Louisville and
overseen by two faculty members
(authors AGF and WCS).
Table 2. Statistical significance of different viewing modalities.
Sensitivity (true positive rate)
Mean
difference
Comparison of evaluator’s viewing modalities
Non-parametric
p value*
Initial image
Brightness and contrastadjusted image
3.8
0.0156
Initial image
Sharpened image
8.9
0.0029
Initial image
LCD density analysis
38.4
0.0005
Brightness and contrastadjusted image
Sharpened image
5.1
0.0156
Brightness and contrastadjusted image
LCD density analysis
34.6
0.0005
Sharpened image
LCD density analysis
29.5
0.0005
Specificity (true negative rate)
Mean
difference
Comparison of evaluator’s viewing modalities
Initial image
Brightness and contrastadjusted image
-1.4
Non-parametric
p value*
0.3453
Initial image
Sharpened image
-3.6
0.0170
Results
Initial image
LCD density analysis
-2.6
0.0818
Table 1 shows the mean values,
standard deviations, coefficients of
variation, standard errors, and 95%
confidence intervals for sensitivity
and specificity for the 12 evaluators.
Table 2 shows the significance of
the differences in the performance
of the evaluators using the different
viewing modalities, based on the
nonparametric p value produced by
the Wilcoxon signed-rank test. It is
generally accepted that the difference
between two modalities is considered significant if the p value is less
than 0.05, and the lower the p value,
the more significant the result.23
For this study, sensitivity equaled
the total number of Class 3 lesions
assessed independently by the
evaluators and recorded by the
study coordinator for surfaces in the
image set confirmed by the attending dentist to have caries in the
dentin, divided by the total number
of such confirmed surfaces (28).
When viewing the initial image,
sensitivity was low (30%). Use of
Brightness and contrastadjusted image
Sharpened image
-2.2
0.1293
Brightness and contrastadjusted image
LCD density analysis
-1.2
0.4082
Sharpened image
LCD density analysis
+1.0
0.4778
*Based on Wilcoxon signed-rank test.
the brightness and contrast and
sharpening filters improved evaluator performance only modestly
(34–39%). On the other hand,
use of the LCD density analysis
tool produced a sensitivity (69%)
which more than doubled that of
the initial image. In terms of significance, when the evaluators used
the LCD density analysis tool, their
results were much more significant
(p = 0.0005) compared to when
they merely visually assessed the
radiographs or used the filters.
The LCD density analysis was
performed by each evaluator on
each surface by selecting the desired
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proximal region to be analyzed
using a custom v-tool (shown in
Fig. 2 and 3) that executed the
calculation automatically. When
a calculation is run, the density
analysis automatically conducts nine
separate calculations by moving the
apex of the v-tool inside the yellow
box (ROI tool) shown in the image,
with the greatest extent of the decay
being displayed. The evaluators also
were given the option to manually
override the ROI tool by moving the
apex of the v-tool inside the yellow
box that updates the calculation.
Evaluators had the further option
of running the software in a fully
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Caries Detection and Prevention Utility and effectiveness of computer-aided diagnosis of dental caries
manual mode when they traced the
tooth edge and the dentinoenamel
junction.
The LCD density analysis
provided useful information that
improved the evaluators’ ability to
assess surfaces with subtle dentinal
caries, since it more than doubled
their performance compared to their
visual assessment of the initial image.
The specificity results are outlined
in the lower half of Tables 1 and
2. Specificity is defined as the total
number of surfaces diagnosed as
Class 0, 1, or 2 (caries-free or caries
only in the enamel) by the evaluators and recorded by the study coordinator for surfaces in the image
set that were originally diagnosed
as such by the attending dentist,
divided by the total number (48)
of such surfaces diagnosed by the
attending dentist. The mean value
of specificity for the 12 evaluators
on these surfaces was greater than
90% for all viewing modalities,
ranging from 93–97% depending
on the modality, indicating that the
evaluators easily identified surfaces
that did not need to be restored
(based on the attending dentist’s
diagnosis), regardless of which
modality was used. In addition, in
most cases there was no significant
difference between the modalities
(p > 0.05 in all cases but one).
Therefore, the LCD did not have
a statistically significant negative
impact in terms of prompting the
need for unnecessary restorations.
The variation in performance
between the 12 evaluators is evident
in Table 1 by the values for standard
deviation, coefficient of variation,
standard error, and 95% confidence
interval. For sensitivity, the range
is large between evaluators viewing
the initial image, the brightness and
contrast-adjusted image, and the
sharpened image, but it is noticeably
smaller when they used the LCD,
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March/April 2011
best shown by comparing the coefficients of variation. For specificity,
the variation in performance among
evaluators is relatively small and
is not significantly dependent on
viewing modality.
Discussion
The attending dentist who provided
the radiographs for this study used
the LCD in his practice. He found
all 28 of the surfaces with dentinal
caries that were retrospectively
assessed by the evaluators. At the
same time, he experienced no false
positives. However, unlike the
evaluators, he had several years of
experience in using the LCD in a
clinical environment. In addition,
he had the advantages of being able
to conduct an oral examination and
to use his knowledge of the patient’s
age, dietary habits, caries history,
and oral hygiene in his diagnosis.
Truth (the goal standard) for
specificity was determined differently than it was for sensitivity in
this study. Since the attending dentist clearly was not going to open
patients’ teeth to prove that they
did not have caries in the dentin,
his diagnoses of surfaces were based
on following the surfaces for several
years during patients’ recall visits.
He also took additional radiographs
during follow-up visits to reassess
the state of the sites of concern and
used the LCD to aid in those reassessments. This method also is used
in medical radiology, because no
one would be willing to conduct (or
undergo) invasive surgery to prove
true negatives.24-26
It also is important to note that
no false negatives were involved in
the calculation of sensitivity, nor
were any false positives involved in
the calculation of specificity, because
the evaluators did not see or treat
the patients in this retrospective
study. For the purposes of this study,
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www.agd.org
sensitivity equals the evaluators’
true positive rate, while specificity
reflects their true negative rate.
The wide variation in the evaluators’ ability to find surfaces needing
restoration using the unaided eye
could be due to the radiographs
with obvious dentinal caries being
excluded from this study; the
remaining cases were subtle and
required careful inspection of the
radiographs. The amount of time
spent by each evaluator on any radiograph was not controlled; therefore,
some evaluators may have performed
better (or worse) compared to others
because they spent more (or less)
time inspecting the radiographs.
In addition, it should be noted
that none of the evaluators were
using digital radiography or the
LCD in their jobs in the school
clinic. Still, with limited training
and no extended period of experience, the LCD clearly helped the
evaluators find significantly more
cases of dentinal caries that needed
to be restored; it also reduced the
statistical spread among evaluators
in the sensitivity results. At the same
time, this tool appeared to have
essentially no negative impact on
the evaluators’ specificity (that is, it
did not cause them to significantly
misdiagnose more surfaces as having
dentinal caries that otherwise did
not need restoration).
Conclusion
CAD software can be very useful in
extracting additional information
from digital radiographs to help
dentists diagnose and monitor proximal caries. The LCD program used
in this study more than doubled the
evaluators’ performance in detecting
early caries that needed restoration,
while not causing a significant
number of unnecessary restorations.
The evaluators in this study received
a minimal amount of training
(approximately one hour) and had
no prior experience with the LCD.
The same program can be used to
monitor enamel caries sites over
time to determine if noninvasive
treatments are arresting (or possibly
recalcifying) the sites.
It was possible to conduct this
study with the caries detection
software alone because the images
were provided in DICOM format.
Similar studies could be conducted
with images from other sensors if
they were saved in DICOM format.
Acknowledgements
The authors wish to thank the
UCLA Statistical/Biomathematical
Consulting Clinic, Los Angeles, for
assisting in the statistical analyses
of the study data. The authors also
wish to thank Professor Kunio Doi,
director of the Kurt Rossmann
Laboratories for Radiologic Image
Research, Department of Radiology,
University of Chicago, for providing
information on the status of CAD
in medical radiology and for providing information on how normals
(true negatives) are established in
medical imaging.
Disclaimer
The LCD and associated intellectual
property are owned by Carestream
Health, Inc. (formerly a division of
Eastman Kodak), Rochester, New
York. The device is manufactured in
the U.S. for Carestream Health by
GA Industries, Rancho Palos Verdes,
California, and is distributed in the
U.S. by Carestream Dental LLC
(formerly PracticeWorks, LLC),
Atlanta, Georgia, a subsidiary of
Carestream Health, Inc. Logicon is a
trademark of the Northrop Grumman Corporation, Los Angeles.
Dr. Gakenheimer and Ms. Lacina
are employees of Carestream Dental
LLC, and Dr. Gakenheimer is president and CEO of GA Industries.
Author information
Dr. Tracy is a resident, Department
of Surgery, Division of Oral and
Maxillofacial Surgery, University
of Cincinnati in Ohio. During
this study, he was a senior dental
student, School of Dentistry, University of Louisville in Kentucky,
where Drs. Scarfe and Farman
are professors of Radiology and
Imaging Science. Dr. Dykstra is
in clinical practice in Hudsonville,
Michigan. Dr. Gakenheimer is one
of the inventors of and product
line manager for the LCD for
Carestream Dental LLC, where Ms.
Lacina is the product specialist for
the LCD. At the time of this study,
Dr. Scheetz was a professor, Diagnostic Science, Prosthodontics, and
Restorative Dentistry Department,
School of Dentistry, University of
Louisville; he has since retired.
9.
10.
11.
12.
13.
14.
References
1. White SC, Yoon DC. Comparative performance
of digital and conventional images for detecting
proximal surface caries. Dentomaxillofac Radiol
1997;26(1):32-38.
2. Uprichard KK, Potter BJ, Russell CM, Schafer TE,
Adair S, Weller RN. Comparison of direct digital
and conventional radiography for the detection
of proximal surface caries in the mixed dentition. Pediatr Dent 2000;22(1):9-15.
3. Syriopoulos K, Sanderink GC, Velders XL, van
der Stelt PF. Radiographic detection of approximal caries: A comparison of dental films and
digital imaging systems. Dentomaxillofac Radiol
2000;29(5):312-318.
4. Nair MK, Nair UP. An in-vitro evaluation of Kodak Insight and Ektaspeed Plus film compared
with a CMOS detector for natural proximal caries: ROC analysis. Caries Res 2001;35(5):354359.
5. Hintze H, Wenzel A, Frydenberg M. Accuracy of
caries detection with four storage phosphor systems and E-speed radiographs. Dentomaxillofac
Radiol 2002;31(3):170-175.
6. Abreu M Jr, Mol A, Ludlow JB. Performance of
RVGui sensor and Kodak Ektaspeed Plus film for
proximal caries detection. Oral Surg Oral Med
Oral Pathol Oral Radiol Endod 2001;91(3):381385.
7. Han WJ. A comparison of film and 3 digital imaging systems for natural dental caries detection: CCD, CMOS, PSP, and film. Korean J Oral
Maxillofac Radiol 2004;34:1-6.
8. Khan EA, Tyndall DA, Ludlow JB, Caplan D.
Proximal caries detection: Sirona Sidexis versus
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Bottenberg P. Approximal caries diagnosis after
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systems: Interobserver agreement and comparison to histological hard-tissue sections. Caries
Res 2008;42(1):57-61.
Hintze H. Diagnostic accuracy of two software
modalities for detection of caries lesions in digital radiographs from four dental systems. Dentomaxillofac Radiol 2006;35(2):78-82.
Castro VM, Katz JO, Hardman PK, Glaros AG,
Spencer P. In vitro comparison of conventional
film and direct digital imaging in the detection
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2007;36(3):138-142.
Alkurt MT, Peker I, Bala O, Altunkaynak B. In
vitro comparison of four different dental x-ray
films and direct digital radiography for proximal
caries detection. Oper Dent 2007;32(5):504509.
Yoon DC, Wilensky GD, Neuhaus JA, Manukian
N, Gakenheimer DC. Quantitative dental caries
detection system and method, U.S. patent
5,742,700. April 21, 1998. Washington, D.C.:
U.S. Patent Office.
U.S. Food and Drug Administration, Center for
Devices and Radiological Health. Summary of
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html.
Gakenheimer DC. The efficacy of a computerized
caries detector in intraoral digital radiography. J
Am Dent Assoc 2002;133(7):883-890.
Wenzel A. Computer-automated caries detection in digital bitewings: Consistency of a program and its influence on observer agreement.
Caries Res 2001;35(1):12-20.
Wenzel A, Hintze H, Kold KM, Kold S. Accuracy
of computer-automated caries detection in digital radiographs compared with human observers. Eur J Oral Sci 2002;110(3):199-203.
Gakenheimer DC. Computer-automated caries
detection tools: A big payoff is possible when
user judgment is combined with the tool. Eur J
Oral Sci 2003;111(2):179-181.
National Institutes of Health. Diagnosis and
management of dental caries throughout life:
NIH consensus statement. 2001;18(1):1-24.
Horowitz AM. A report on the NIH Consensus
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Management of Dental Caries Throughout Life. J
Dent Res 2004;83 Spec No C:C15-C17.
Pitts NB. Modern concepts of caries measurement. J Dent Res 2004;83 Spec No C:C43-C47.
Doi K. Computer-aided diagnosis in medical
imaging: Historical review, current status and
future potential. Computer Med Imag Graph
2007;31(4-5):198-211.
Altman DG. Practical statistics for medical research. New York: Chapman & Hall;1991.
Doi K. Personal communication concerning verification of normals in medical radiology. Chicago, IL; September 21, 2009.
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Caries Detection and Prevention Utility and effectiveness of computer-aided diagnosis of dental caries
25. Li F, Aoyama M, Shiraishi J, Abe H, Li Q, Suzuki
K, Engelmann R, Sone S, MacMahon H, Doi K.
Radiologists’ performance for differentiating
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2004;183(5):1209-1215.
26. Li F, Arimura H, Suzuki K, Shiraishi J, Li Q, Abe H,
Engelmann R, Sone S, MacMahon H, Doi K.
Computer-aided detection of peripheral lung
cancers missed at CT: ROC analyses without
and with localization. Radiology 2005;237(2):
684-690.
Manufacturers
Carestream Dental LLC, Atlanta, GA
800.944.6365, www.carestreamdental.com
GC America Inc., Alsip, IL
800.323.7063, www.gcamerica.com
COMMENT
144
March/April 2011
General Dentistry
www.agd.org
trauma in Primary/Young teeth
Management of multiple trauma avulsion of
anterior primary teeth: A three-year follow-up
Claudia Marina Viegas, MDS Ana Carolina Scarpelli, MDS Joao B. Novaes-Junior, PhD
Henrique Pretti, MDS Alexandre Fortes Drummond, PhD Saul Martins Paiva, PhD
n
n
n
n
Dental trauma can cause physical, esthetic, and psychological
problems. This paper presents the case of a 2-year-old boy
who suffered multiple avulsions of the maxillary anterior teeth.
Treatment consisted of fixed orthodontic appliances with artificial
anterior teeth. The clinical follow-up lasted for three years. The
D
ental trauma in children can
create physical, esthetic, and
psychological problems for
both the child and the parents.1
Avulsion is a dental trauma injury
characterized by the complete
dislocation of the tooth or teeth
from the alveolus.2 The premature
loss of incisors is a concern for the
parents of children affected by this
type of trauma, and the quest for
treatment often includes anxiety
regarding esthetic and functional
harm.3 Although infrequent, avulsion can result in consequences to
the permanent teeth, including
enamel defects, which are clinically diagnosed as discoloration.4
Malformations, impacted teeth, and
disturbances to the eruption and
development of permanent teeth
also may occur.2
This article describes the diagnosis and treatment of a case of
multiple avulsions of the maxillary
primary incisors and canines suffered by a child who was the victim
of a car accident.
procedure for the re-establishment of esthetic and dental function
was based on a simple, low-cost therapeutic solution. The child
and parents were satisfied with the treatment results.
Received: September 10, 2009
Accepted: December 23, 2009
of Minas Gerais, Brazil, for dental
treatment. The mother presented
three primary teeth and a CT scan.
She said that her son had been
run over by a car three days earlier
and received primary care in the
emergency ward of a public hospital. On the day of the accident,
a CT scan of the boy’s head (Fig.
1) was performed. No fracture or
alteration was diagnosed, but the
child had suffered avulsion of the
maxillary primary incisors and
canines and was referred for dental
treatment (Fig. 2).
During the clinical examination,
the dentist noted the exposure of the
upper alveolar edge and the presence
of visible bone spicules. The region
was cleaned with 0.9% sodium
chloride solution (Farmax) and a
sterile gauze compress (Cremer).
The mother was instructed on
hygiene of the teeth and traumatized region. Recall appointments
were held at two-month intervals to
follow the healing process.
Four months after the initial
visit, the wound had scarred and
a new clinical examination was
performed, noting the presence of
the primary first molars and the
absence of the primary maxillary
second molars. A diagnosis was
Case report
A boy, aged 2 years and 4 months,
was brought by his mother to the
Pediatric Dentistry and Orthodontics Clinic of the Federal University
Fig. 1. A CT scan of the patient’s head,
illustrating the absence of primary
maxillary incisors and canines.
www.agd.org
Fig. 2. A frontal view of the patient after avulsion of the
primary maxillary incisors and canines.
General Dentistry
March/April 2011
145
trauma in Primary/Young teeth Management of multiple trauma avulsion of anterior primary teeth
Fig. 3. The Hyrax appliance, constructed with six artificial maxillary
anterior teeth.
Fig. 4. An intraoral view of the patient nine months after the initial visit,
showing the Hyrax appliance in place.
Fig. 5. The fixed-space maintainer with six artificial maxillary anterior
teeth.
Fig. 6. An intraoral view of the patient 15 months after the initial visit,
showing the fixed-space maintenance appliance in place.
made of atresia of the jaw, associated with mouth breathing and
pacifier sucking. It was decided
to delay treatment until after the
complete eruption of the primary
second molars, which occurred nine
months after the accident.
An esthetic, functional restorative
solution was defined for the atresia
of the maxilla. A Hyrax appliance
(orthodontic palatal split screw
11.0 mm, Morelli Orthodontics)
was created with six artificial maxillary anterior teeth (canines, lateral
incisors, and central incisors), with
bands on the maxillary second
molars and retention on the maxillary first molars.5 The appliance was
activated following the Hyrax activation protocol of ¼ turn in the morning and ¼ turn at night for 14 days
146
March/April 2011
(Fig. 3 and 4). After six months,
the appliance was replaced with a
fixed-space maintainer without an
activation screw and a segmented
palatine arch to not hinder maxillary
growth (Fig. 5 and 6). Photos of the
child were taken three years after the
initial visit (Fig. 7–9).
It is worth noting that the patient
maintained consistent dental
monitoring and that he was advised
to maintain it until the permanent
teeth were fully descended. Both the
child and his mother were very satisfied with the treatment.
Discussion
Whenever possible following avulsion, it is important to locate the
avulsed tooth and perform radiographic examinations to ensure that
General Dentistry
www.agd.org
the missing tooth has not undergone
intrusion.2,4 In the case reported
here, the child had experienced
avulsion of the six maxillary anterior
teeth, which was confirmed by the
CT scan and the avulsed teeth that
the mother brought to the clinic.
Reimplantation of avulsed teeth
is not recommended, as the risks for
a 2-year-old child are numerous and
include aspiration, inflammatory
bone resorption, abscess formation,
and interference with the development of the permanent tooth
germ.2,4 In this case, no reimplantation was performed. In order to
minimize the psychological, physical, and functional repercussions
stemming from the dental trauma,
fixed appliances with artificial teeth
were created.
Fig. 7 and 8. Intraoral views of the patient three years after the initial visit, showing the fixed-space
maintenance appliance in place.
Because the patient’s maxillary
arch constriction was related to
mouth breathing, a maxillary
expansion appliance was produced
first. Rapid expansion of the maxilla is indicated for children when
constriction of the maxillary arch
is related to mouth breathing and
a high palatal vault.6 The Hyrax
appliance was selected because of
its maxillary expansion properties.7,8 The primary first and second
molars were used to anchor the
appliance, since these teeth are
capable of supporting the strong
forces produced during rapid
expansion of the maxilla.8
Following maxillary expansion, a
fixed-space maintenance appliance
was fabricated with artificial anterior
teeth to maintain the space in the
arch due to early loss of the canines
and incisors, which could negatively
affect the normal development of
the dentition. Canines are known to
be important for space maintenance
during the development of the
dentition.9
artificial anterior teeth proved to
be an efficient alternative in the
re-establishment of function and
esthetics. The self-esteem of the
child involved was restored, demonstrating the importance of oral
esthetics. Furthermore, the treatment plan involved a simple and
low-cost procedure, which makes it
useful for a potentially large number
of patients.
Summary
References
Considering the case presented
and the result achieved, the use of
fixed orthodontic appliances with
COMMENT
Acknowledgements
This study was supported by the
State of Minas Gerais Research
Foundation (FAPEMIG), Brazil.
Author information
Drs. Viegas and Scarpelli are on the
faculty of dentistry, Department of
Pediatric Dentistry and Orthodontics, Federal University of Minas
Gerais, Belo Horizonte, MG, Brazil,
where Drs. Pretti, Drummond, and
Paiva are assistant professors and Dr.
Novaes-Junior is an associate professor, Department of Oral Surgery
and Pathology.
1. Cardoso M, Rocha MJC. Traumatized primary
teeth in children assisted at the Federal University of Santa Catarina, Brazil. Dent Traumatol
2002;18(2):129-133.
www.agd.org
Fig. 9. An extraoral view of the patient three
years after the initial visit, showing the
fixed-space maintenance appliance in place.
2. Flores MT, Malmgren B, Andersson L, Andreasen JO, Bakland LK, Barnett F, Bourguignon C, DiAngelis A, Hicks L, Sigurdsson A,
Trope M, Tsukiboshi M, von Arx T; International Association of Dental Traumatology. Guidelines for the management of traumatic dental
injuries. III. Primary teeth. Dent Traumatol 2007;
23(4):196-202.
3. Flores, MT. Traumatic injuries in the primary dentition. Dent Traumatol 2002;18(6):287-298.
4. Wilson CF. Management of trauma to primary
and developing teeth. Dent Clin North Am
1995;39(1):133-167.
5. Biederman W. A hygienic appliance for rapid
expansion. JPO J Pract Orthod 1968;2(2):67-70.
6. da Silva Filho OG, Montes LA, Torelly LF. Rapid
maxillary expansion in the deciduous and mixed
dentition evaluated through posteroanterior
cephalometric analysis. Am J Orthod Dentofacial
Orthop 1995;107(3):268-275.
7. Needleman HL, Hoang CD, Allred E, Hertzberg J,
Berde C. Reports of pain by children undergoing
rapid palatal expansion. Pediatr Dent 2000;
22(3):221-226.
8. Cozzani M, Rosa M, Cozzani P, Siciliani G. Deciduous dentition-anchored rapid maxillary expansion in crossbite and non-crossbite mixed
dentition patients: Reaction of the permanent
first molar. Prog Ortho 2003;4:15-22.
9. Lindsten R, Ogaard B, Larsson E. Anterior space
relations and lower incisor alignment in 9-yearold children born in the 1960s and 1980s. Angle Orthod 2001;71(1):36-43.
Manufacturers
Cremer, Blumenau, SC, Brazil
55.47.3321.8389, www.cremer.com.br
Farmax, Divinopolis, MG, Brazil
0800.941.0080, www.farmax.ind.br
Morelli Orthodontics, Sorocaba, SP, Brazil
800.703.1455, www.morelli.com.br
General Dentistry
March/April 2011
147
oral Medicine, oral Diagnosis
Enalapril-induced angioedema:
A dental concern
Kim K. McFarland, DDS, MSHA
n
Eric Y.K. Fung, PhD
Drug-induced angioedema is a rare but potentially life-threatening
side effect of increased levels of bradykinin. It may be overlooked
and diagnosed as a dental-related problem due to its appearance
as facial swelling. A clear understanding of the pathophysiology
A
ngioedema is an abrupt,
diffuse edematous swelling of the soft tissues of a
localized body area involving the
skin, mucosa, and subcutaneous
tissues. The extremities are most
commonly affected, although the
face, genitals, trunk, and neck also
can be involved.1 This disorder also
is referred to as Quincke’s disease
after the clinician who reported
changes in tissue permeability.2 The
most common cause of this disorder
is mast cell degranulation leading
to the release of histamine or the
activation of bradykinin formation.2
However, in 0.1–1% of patients,
angioedema has been reported as an
adverse side effect of a class of drugs
known as angiotensin-converting
enzyme (ACE) inhibitors.3-5
ACE inhibitors are widely used in
the treatment of essential hypertension and congestive heart failure,
renal failure, and diabetic nephropathy.6-8 This class of drugs blocks the
enzyme that converts angiotensin I
to the potent angiotensin II, which
has vasoconstrictor and sodiumretaining activity.6 As a result, ACE
inhibitors reduce blood pressure by
decreasing peripheral vascular resistance without reflexively increasing
cardiac output, rate, or contractility. Drugs in this class are listed
in the table. ACE inhibitors are
148
March/April 2011
of angioedema can better serve both physicians and dentists in
providing the most appropriate care for patients.
Received: October 21, 2009
Accepted: February 15, 2010
contraindicated during pregnancy
due to increased risk of fetal renal
failure, intrauterine growth retardation, and other congenital defects.6
Side effects of this class of ACE
inhibitors include dry cough, allergic skin rashes, drug fever, altered
sense of taste, postural hypotension,
and hyperkalemia.6 Dry cough is
a common side effect that occurs
in approximately 15% of patients
and is caused by increased levels of
bradykinin. Angioedema is a rare
but potentially life-threatening
adverse side effect that often is
misdiagnosed or overlooked by
some physicians, who may consider
it to be a dental-related problem.2,4,5
This adverse drug effect can occur
at any time during drug treatment
and manifests as swelling of the
face, extremities, lips, mucous
membranes, tongue, glottis, or
larynx.3-5 The following case report
documents a case of drug-induced
angioedema during treatment with
enalapril.
Case report
A 55-year-old man came to a community health center dental clinic
with left facial swelling (Fig. 1).
The patient explained that he was
referred to the dental clinic after visiting the local hospital’s emergency
room, where he was informed that
Table. ACE inhibitors.
Drug
Brand name(s)
Benazepril
Lotensin
Captopril
Capoten
Enalapril
Vasotec
Fosinopril
Monopril
Lisinopril
Prinivil, Tensopril,
Zestril
Moexipril
Univasc
Perindopril
Aceon
Quinapril
Accupril
Ramipril
Altace, Tritace
Trandolapril
Mavik
General Dentistry
www.agd.org
Fig. 1. Front view of the patient depicting facial
swelling.
he had a dental abscess that was
causing his face to swell. The patient
had a medical history of idiopathic
hypertension, chronic obstructive
pulmonary disease, gastrointestinal
problems, and endogenous depression. The patient was taking the following medications on a daily basis:
metoprolol 50 mg; omeprazole 40
mg; amlodipine 10 mg; enalapril 10
mg; and escitalopram 20 mg; he also
was taking clonazepam 0.5 mg twice
daily. The patient did not report any
known drug allergies.
A clinical and radiographic
examination of the patient’s teeth
revealed no apparent dental decay
or abscess. The patient was partially
edentulous, was missing most of
his posterior teeth, and recently
had tooth No. 20 extracted (Fig. 2).
The remaining teeth were not sensitive to temperature or percussion.
No purulent exudate or swelling
was associated with the teeth, but
chronic generalized periodontal
disease was present. Tooth No. 21
exhibited vertical bone defects and
deep periodontal pockets measuring more than 9.0 mm. However,
the periodontal disease did not
appear to be the cause of the facial
swelling, which was confined to the
interstitial spaces surrounding the
facial musculature.
A medical consultation by a
community health center physician was provided to rule out the
possibility of allergic reaction. The
physician determined that, since the
facial swelling was unilateral and
the patient had no history of drug
allergies, the cause of the swelling
was a dental infection. The dentist
informed the patient about his periodontal disease but noted that the
periodontal disease might not be the
cause of the swelling. The dentist
prescribed amoxicillin 500 mg, 1
gm stat and 500 mg every six hours
until gone, and acetaminophen with
hydrocodone 5/500 mg, one tablet
every six hours as needed for pain.
After leaving the dental clinic,
the patient crossed the street to the
neighborhood pharmacy to fill the
prescriptions. While at the pharmacy, the patient called the dentist
and asked if he could have tooth
No. 21 removed. The dentist agreed,
because removal could empirically
rule out a dental infection as a
potential cause of the facial swelling.
The patient returned immediately to
the dental clinic.
Two cartridges of local anesthetic,
2% lidocaine 1:100,000 epinephrine, were administered via an
inferior alveolar nerve block and
local infiltration. A simple forceps
extraction of tooth No. 21 was
performed. The patient was given
postsurgery instructions, both orally
and in writing, and was dismissed.
Approximately two hours later,
a nurse at the emergency room of
the local hospital called the dentist
to say that the patient had returned
to the emergency room with left
facial swelling. The emergency
room doctor needed to know what
drugs had been administered to the
patient while he was at the dental
clinic and what procedure had
been performed. The patient was
extremely concerned that his facial
swelling had not decreased despite
removal of the tooth. After being
examined by the emergency room
staff, the patient was instructed
to return home and follow the
postoperative instructions provided
by the dental clinic.
Later that evening, the patient
returned to the hospital emergency
room with difficulty breathing.
The patient’s facial swelling had
diminished on the left side but was
now present on the right side. At
the emergency room, the following
drugs were administered to the
patient: diphenhydramine 50 mg
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Fig. 2. Dental radiograph demonstrating
periodontal disease and recent tooth
extraction.
(IV), famotidine 40 mg (IV), methylprednisolone 125 mg (IV), and
epinephrine (1:1,000) 0.3 mg subcutaneously. The emergency room
physician instructed the patient to
stop taking enalapril. The patient
was instructed to take prednisone
20 mg twice daily for five days and
hydroxyzine 50 mg every six hours
as needed. The patient responded
well to drug treatment and made a
full recovery.
Discussion
Angioedema can be induced by
allergic reactions or NSAIDs,
which are frequently accompanied
by urticaria.6 However, ACE
inhibitor-induced angioedema is
seldom accompanied by hives.2
Although enalapril-induced
angioedema can occur at any time
during drug therapy, it usually
occurs during the first week.9 In
addition, it is more likely to occur
in blacks, patients over the age of
65, and patients with a history of
drug rash or seasonal allergies.3,4,10
ACE inhibitor-induced angioedema
is caused by increased levels of
bradykinin and impairment of
aminopeptidase P and dipeptidyl
peptidase IV, which are involved
in the metabolism of substance P
and bradykinin.11,12 Most cases of
ACE inhibitor-induced angioedema
General Dentistry
March/April 2011
149
oral Medicine, oral Diagnosis Enalapril-induced angiodema: A dental concern
resolve upon cessation of the
medication.4,5 Common drug treatments may include oral treatment
with antihistamines, corticosteroids, and systemic administration
of epinephrine.4,6
In this instance, the patient had
been taking enalapril for more than
two years; therefore, etiopathic
angioedema must be considered
in the differential diagnosis of
patients with facial swellings of an
unknown origin. An awareness of
this issue and a clear understanding
of the pathophysiology of angioedema can benefit both physicians
and dentists in providing the most
appropriate treatment.
allergic reactions, especially when
patients present with facial swelling
of an unknown origin.
Disclaimer
The authors have no financial,
economic, or commercial interests
related to the topic or drugs presented in this article.
5.
6.
7.
8.
Author information
Dr. McFarland is an assistant clinical professor, Department of Oral
Biology, University of Nebraska
Medical Center College of Dentistry in Lincoln, where Dr. Fung is
a professor of pharmacology.
9.
10.
References
Summary
Swelling of the lips, face, or oral
cavity could indicate an idiopathic
allergic reaction to an ACE inhibitor. Although patients may have a
long history of taking ACE inhibitors with no resulting side effects,
the presence of swelling could indicate an allergic reaction. It is very
important to rule out idiopathic
1. Kaplan AP, Greaves MW. Angioedema. J Am
Acad Dermatol 2005;53(3):373-388.
2. Neville BW, Damm DD, Allen CM, Bouquot JE.
Oral and maxillofacial pathology, ed. 3. St. Louis: Saunders;2009.
3. Morimoto T, Gandhi TK, Fiskio JM, Seger AC,
So JW, Cook EF, Fukui T, Bates DW. An evaluation of risk factors for adverse drug events associated with angiotensin-converting enzyme
inhibitors. J Eval Clin Pract 2004;10(4):499509.
4. Kostis JB, Kim HJ, Rusnak J, Casale T, Kaplan A,
Corren J, Levy E. Incidence and characteristics of
11.
12.
angioedema associated with enalapril. Arch Intern Med 2005;165(14):1637-1642.
Nussberger J, Cugno M, Cicardi M. Bradykininmediated angioedema. N Engl J Med 2002;347
(8):621-622.
Katzung, BG, Masters SB, Trevor AJ. Basic and
clinical pharmacology, ed 11. New York: McGrawHill Medical;2009.
August P. Initial treatment of hypertension. N
Engl J Med 2003;348(7):610-617.
Verdecchia P, Reboldi G, Angeli F, Gattobiglo R,
Bentivoglio M, Thijs L, Staessen JA, Porcellati C.
Angiotensin-converting enzyme inhibitors and
calcium channel blockers for coronary heart disease and stroke prevention. Hypertension
2005;46(2):386-392.
Dean DE, Schultz DL, Powers RH. Asphyxia due
to angiotensin converting enzyme (ACH) inhibitors mediated angioedema of the tongue during
the treatment of hypertensive heart disease. J
Forensic Sci 2001;46(5):1239-1243.
Burkhart DG, Brown NJ, Griffin MR, Ray WA,
Hammerstrom T, Weiss S. Angiotensin converting
enzyme inhibitor-associated angioedema: Higher risk in blacks than whites. Pharmacoepidemiol Drug Saf 1996;5(3):149-154.
Cugno M, Nussberger J, Cicardi M, Agostoni A.
Bradykinin and the pathophysiology of angioedema. Int Immunopharmacol 2003;3(3):311317.
Jurakic Toncic R, Marinovic B, Lipozencic J. Nonallergic hypersensitivity to nonsteroidal antiinflammatory drugs, angiotensin-converting
enzyme inhibitors, radiocontrast media, local
anesthetics, volume substitutes and medications
used in general anesthesia. Acta Dermatovenerol Croat 2009;17(1):54-69.
COMMENT
150
March/April 2011
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oral Diagnosis
Interdental papilla overgrowth
John K. Brooks, DDS
Nikolaos G. Nikitakis, DDS, PhD
A 21-year-old woman was referred to a specialized oral
medicine clinic by her general dentist for evaluation of
a nodule on her maxillary anterior gingiva. The patient
first noticed the lesion when she was 15 years old. The
mass gradually increased in size, but relatively rapid
growth was noticed during the last few months. The
lesion bled mildly during toothbrushing but otherwise
was asymptomatic. The patient was a nonsmoker and her
oral hygiene was satisfactory. Her medical history was
significant for hypothyroidism, which had been managed
with levothyroxine for the last few years, and mitral
valve prolapse with regurgitation. Clinical examination
revealed a nontender nodule of normal coloration and
fibrous consistency arising from the interdental papilla
between the right maxillary central and lateral incisors
(Fig. 1). A periapical radiograph did not reveal any bone
defect in the area. The lesion was surgically removed and
submitted for histopathological examination (Fig. 2).
Which of the following pathologic disorders is the most
compatible diagnosis?
A. Oral focal mucinosis
B. Peripheral giant cell granuloma
C. Peripheral ossifying fibroma
D. Peripheral odontogenic fibroma
E. Pyogenic granuloma
Diagnosis is on page 154.
Fig. 2. Islands of odontogenic epithelium are visible in a background of
fibrous connective tissue (H&E stain, magnification 200x).
Fig. 1. Sessile mass on the maxillary anterior gingiva.
Author information
Dr. Brooks is a clinical professor, Department of Diagnostic Sciences and
Pathology, Dental School, University of Maryland, Baltimore. Dr. Nikitakis is an
assistant professor, Department of Oral Pathology and Oral Medicine, School
of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
152
March/April 2011
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Rubbery palatal mass
John K. Brooks, DDS
Nikolaos G. Nikitakis, DDS, PhD
A 42-year-old woman sought evaluation at the University of Maryland Dental School urgent care clinic for
an oral “swelling” that had gradually increased in size
during the last seven or eight years. The patient reported
constant, intense, sharp pain associated with the lesion,
often radiating to her right ear and down her neck. The
pain was exacerbated by opening or closing her mouth,
swallowing, and speaking. The severity of the pain led
to sleep disruption; also, the patient recently began
Which of the following is the most appropriate diagnosis?
A. Pleomorphic adenoma
B. Inflammatory myofibroblastic tumor
C. Fibrosarcoma
D. Leiomyosarcoma
E. Spindle cell carcinoma
Diagnosis is on page 154.
Fig. 1. Expansile soft tissue mass along the
posterior hard palate.
experiencing right-sided headaches. The medical history
was significant for hypertension, which was controlled
by amlodipine, clonidine, and metroprolol. In addition,
the patient was taking escitalopram oxalate for depression. The patient denied alcohol or tobacco usage.
Clinical examination revealed a 2.5 cm x 2.0 cm
irregular, rubbery mass arising from the palatal aspect
of the maxillary right tuberosity. The tumor was
bilobed with a deep central fissure; the buccal aspect
of the mass was mobile, while the palatal component
was firm and exhibited multiple, linear erythematous
streaks (Fig. 1). The inferior surface was ulcerated,
attributed to chronic trauma from the opposing third
molar. The lesion appeared to have caused rotation and
buccal displacement of the maxillary second molar.
There was no lymphadenopathy. An MRI indicated a
right palatal mass with a hyperintense signal (Fig. 2).
An incisional biopsy was performed for histopathologic
review (Fig. 3). Immunohistochemical staining was
focally positive for actin.
Fig. 2. A heterogeneous signal with diffuse
borders is seen on the MRI (arrows). The tumor
appears to have caused rotation and buccal
displacement of the maxillary second molar.
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Fig. 3. Numerous spindle cells are set
against a collagenous background. Scattered
inflammatory cells are present as well (H&E
stain, magnification 200x).
General Dentistry
March/April 2011
153
Answers
Oral Diagnosis
Interdental papilla
overgrowth
Diagnosis:
D. Peripheral odontogenic
fibroma
Peripheral odontogenic fibroma
(POF) is a relatively rare benign
odontogenic tumor of ectomesenchymal origin and is regarded as
the extraosseous counterpart of
the central odontogenic fibroma.
Typically, POFs are clinically
described as indolent, singular, firm
sessile masses of normal mucosal
surface and color. These tumors
arise in the tooth-bearing regions
of the jaws, with a greater affinity
for the mandibular anterior and
premolar gingiva. Less frequently,
lesions occur on the maxillary
gingiva and the edentulous alveolar
mucosa. Lesional displacement
of teeth is an uncommon feature.
The size of reported tumors has
ranged from 0.3–3.4 cm. The mean
age of affected patients is 37, and
the tumors have a slight female
predilection. Although POFs are
not locally destructive, resorption
of the subjacent bone can be seen
infrequently on radiographs or
during surgical exploration.
Microscopically, lesions exhibit a
nonencapsulated epithelium with
narrow, deeply plunging rete ridges.
The submucosa displays interwoven
fascicles of fibrous connective tissue,
occasionally interspersed with a
more myxoid stroma. Islands of
inactive odontogenic epithelial rests
are scattered within the stroma. In
addition, multinucleated giant cells
and spherical dystrophic calcifications, resembling dentin, cementum, and/or bone, can appear in the
154
March/April 2011
underlying connective tissue. Cut
surfaces of surgical specimens often
exhibit a gritty texture.
The treatment of choice for POFs
is complete surgical resection;
however, it should be emphasized
that recurrence has been reported
as high as 50%, usually within two
years postoperatively. Moreover,
at least 20% of this subset will
demonstrate a propensity to recur
two or more times.
References
1. Buchner A, Merrell PW, Carpenter WM.
Relative frequency of peripheral odontogenic tumors: A study of 45 new cases
and comparison with studies from the
literature. J Oral Pathol Med 2006;
35(7):385-391.
2. Odontogenic cysts and tumors. In: Neville
BW, Damm DD, Allen CW, Bouquot JE. Oral
& maxillofacial pathology, ed. 3. St. Louis:
Saunders/Elsevier;2009:727-729.
3. Ritwik P, Brannon RB. Peripheral odontogenic fibroma: A clinicopathologic study of
151 cases and review of the literature with
special emphasis on recurrence. Oral Surg
Oral Med Oral Pathol Oral Radiol Endod
2010;110(3):357-363.
Rubbery palatal mass
Diagnosis:
B. Inflammatory
myofibroblastic tumor
The term inflammatory myofibroblastic tumor (IMT) refers to a rare,
diverse group of lesions with varying
etiologies that present as spindle
cell proliferations with an intense
inflammatory component. There is
a wide spectrum of phenotypes of
IMTs, with subsets ranging from a
reactive lesion to a benign neoplasm
or to a more aggressive or possbile
malignant process. The most
frequent site of occurrence of IMTs
involves the lungs, with fewer cases
General Dentistry
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found in the visceral organs and
the head and neck. Only a small
number of oral IMTs have been
documented, mostly occurring on
the buccal mucosa.
The mean age of patients with oral
IMTs is 35; in contrast, the majority
of affected patients with extraoral
lesions are diagnosed during the first
two decades of life (mean age = 10).
Generally, there is a slight female
predilection. An alarming feature
of oral IMTs is their reported rapid
growth rate, often attaining sizes
of 2.0 cm in less than two months.
The majority of oral IMTs are
characterized as solitary, painless,
erythematous nodules with a firm
consistency.
Histopathologically, three basic
cellular patterns of IMT have been
recognized, all of which display
specialized spindle cell populations
of myofibroblasts. One variant is
composed of scattered myofibroblasts in an edematous myxoid
background, admixed with plasma
cells, lymphocytes, eosinophils, and
dispersed blood vessels. The second
pattern is predominated with dense
aggregations of spindle cells in a
myxoid and collagenized setting,
with clusters of plasma cells and
lymphoid nodules. Each of these
two subtypes exhibits ganglion-like
cells. The third subset is distinguished by the presence of collagen
sheets with sparse populations
of plasma cells and eosinophils.
Immunohistochemical staining
may offer diagnostic and prognostic
applications.
The modality of treatment for oral
IMTs usually entails complete surgical excision, although select cases
with a more aggressive behavior
respond to chemotherapeutic
agents. Of note, at least one-fourth
of oral IMTs extend into contiguous
structures. Although the limited
number of oral cases of IMT have
not demonstrated recurrence or
malignant transformation, patients
should undergo reassessment for at
least 10 years. Overall, the recurrence rate for IMTs is 19–25%,
and 8–18% of lesions may become
malignant.
References
1. Coffin CM, Fletcher JA. Inflammatory
myofibroblastic tumour. In: Fletcher, CDM,
Unni KK, Mertens F, eds. World health
organization classification of tumours.
Pathology and genetics of tumours of soft
tissue and bone. Lyon: IARC Press;2002:
91-93.
2. Brooks JK, Nikitakis NG, Frankel BF,
Papadimitriou JC, Sauk JJ. Oral inflammatory myofibroblastic tumor demonstrating
ALK, p53, MDM2, CDK4, pRb, and Ki-67
immunoreactivity in an elderly patient. Oral
Surg Oral Med Oral Pathol Oral Radiol
Endod 2005;99(6):716-726.
Self-Instruction
Exercise No. 255
Exercise No. 256
Exercise No. 257
March/April 2010, p. 108
1. A
2. A
3. C
4. D
5. B
6. A
7. D
8. C
9. A
10. B
11. D
12. C
13. B
14. D
15. C
March/April 2010, p. 124
1. A
2. C
3. B
4. C
5. B
6. B
7. D
8. B
9. A
10. A
11. C
12. A
13. C
14. D
15. A
March/April 2010, p. 138
1. C
2. B
3. C
4. A
5. D
6. C
7. B
8. B
9. D
10. A
11. C
12. B
13. A
14. D
15. C
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LSK121
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155
2010 Reviewers
We express our gratitude here to the following individuals who reviewed materials for General Dentistry
from January 1 to December 31, 2010.
Sidney L. Adler, DDS, MAGD
Bronx, NY
Bernardo Ferreira Brasileiro, DDS, MS, PhD
Aracaju,SE,Brazil
T. Bob Davis, DMD, MAGD
Dallas, TX
Guy M. Hanson, DDS, MAGD
Boise, ID
SeyedHamzehAghaie,DDS,FAGD
Thornhill, ON, Canada
John K. Brooks, DDS
Owings Mills, MD
Paul Dawood, DDS, FAGD
Anaheim, CA
Tina Heil, DMD, FAGD
Suwanee, GA
Mert N. Aksu, DDS
Ann Arbor, MI
Ronald S. Brown, DDS
Washington, DC
Ronald W. Deenik, DDS, FAGD
Holland, MI
Marc C. Henderson, DDS, FAGD
New Milford, CT
A. Lichelle Aldana, DDS, FAGD
Salem, MA
Joseph B. Burley, DDS, FAGD
Hagerstown, MD
Shihab M. Diais, DDS, FAGD
Odessa, TX
Gerald N. Hino, DDS, MAGD
Yakima, WA
Charles D. Aldridge, DDS, MAGD
Bend, OR
Carroll R. Butler, DDS, FAGD
Kerrville, TX
Michael G. Dragon, DDS, FAGD
Abita Springs, LA
William L. Hoch, DMD, MAGD
Beaver, PA
Saad Abdullah M. Al-Harbi, BDS
Jeddah, Saudi Arabia
Michael J. Calabrese, DMD, MAGD
Feeding Hills, MA
Valerie A. Drake, DDS, FAGD
Harlingen, TX
Isaac A. House, DDS, FAGD
Haughton, LA
Francis W. Allen, DMD, MAGD
Salem, OR
Jefferson R. Call, DMD, FAGD
Hillsboro, OR
Dwight D. Duckworth, DDS, MAGD
Springdale, AR
James H. Howard, DDS, FAGD
Omaha, NE
Wael M. Al-Omari, BDS, MDSC, PhD
Irbid, Jordan
Thomas H. Callahan, DDS, MAGD
Tiger, GA
Stephen W. Durham, DMD, FAGD
Beaufort, SC
Kimberly Quan Hubenette, DDS, MAGD
Santa Rosa, CA
Thomas L. Anderson, DDS
Prairie Village, KS
Greg D. Camfield, DMD, FAGD
Creve Coeur, MO
James S. Eaves, DDS, FAGD
Manassas, VA
Kevin D. Huff, DDS, MAGD
Dover, OH
Paul A. Andrews, DDS
Lake Mary, FL
Jonathan G. Campbell, DDS, FAGD
Salt Lake City, UT
Rabeh Ebeed, DDS, MAGD
Hudson, NH
Fahmida Hussain, DMD, FAGD
Philadelphia, PA
John R. Antonelli, DDS
Davie, FL
Kim L. Capehart, DDS
Simpsonville, SC
Denise Estafan, DDS, MS
New York, NY
Eric G. Jackson, DDS, FAGD
Downers Grove, IL
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Kodiak, AK
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Lawton, OK
Douglas R. Fabiani, DMD, FAGD
Sarasota, FL
Lanny Jacob, DMD
Winnipeg, MB, Canada
Andrew J. Avillo, DDS, FAGD, ABGD
San Diego, CA
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Cambridge, MD
George T. Felt, DDS, MAGD
Meredith, NH
Thomas C. Jagor, DDS, MAGD
Atlanta, GA
Michael L. Babinski, DMD, MAGD
Colchester, CT
John F. Carpenter, DMD, MAGD
New Windsor, NY
Michael A. Forman, DDS
Vaughn, ON, Canada
Steven E. Janko, DMD, MAGD
Hopedale, MA
Marsha A. Babka, DDS, FAGD
Berwyn, IL
James L. Carroll, DDS, MAGD
Auburn, AL
Kevin A. Jasinski, DMD, FAGD
Mc Coll, SC
WilliamR.Baez,DDS,FAGD,ABGD
Aldie, VA
Stephen W. Carstensen, DDS, FAGD
Bellevue, WA
Lucas Da Fonseca Roberti Garcia,
DDS, MSc, PhD
RibeiraoPreto,SP,Brazil
Saul Bahn, DMD, MScD
Ambrose Chan
Hisham Barakat, DDS, MAGD
Vienna, VA
Richard M. Chapin, DDS
Kinston, NC
Timothy M. Barber, DMD, MAGD, ABGD
The Woodlands, TX
William R. Chase, DDS, FAGD
Cathedral City, CA
Peter G. Bastian, DDS, MAGD
Huntsville, ON, Canada
Leslie C. Chew, DDS
Richmond, BC, Canada
Willie K. Beasley, DDS, MAGD
Mandeville, LA
Venu M Chimmiri, DDS, FAGD
South Windsor, CT
John D. Beckwith, DMD, FAGD
Hillsborough, NJ
John J. Christensen, DDS, FAGD
Layton, UT
Joseph A. Belsito, DDS, FAGD
Windsor, ON, Canada
Ward W. Clemmons, DDS, FAGD
Fort Smith, AR
Steven D. Bender, DDS
Plano, TX
Randolph A. Coffey, DMD, MAGD, ABGD
Bradenton, FL
Charles E. Berner, DDS, MAGD
Cleveland, OH
Harvey S. Cohen, DDS, MAGD
Baltimore, MD
Harold Biller, DDS, MAGD
Jamaica, NY
Kaianne M. Conibear, DDS
Orlando, FL
Wesley S. Blakeslee, DMD, FAGD
Manasquan, NJ
Mullen O. Coover, DDS, MAGD, ABGD
Mount Pleasant, SC
Warren E. Boardman, DMD, MAGD
Ridgewood, NJ
Steven A. Corben, DMD, FAGD
Danvers, MA
Rebecca M. Bockow, DDS
Seattle, WA
Adam P. Cormier, DDS
Bossier City, LA
Sallyanne Bonner, DMD, MAGD
Lebanon, NJ
Bruce E. Cunningham, DMD, MAGD
Jacksonville, AL
Barry L. Bowden, DDS, MAGD
Austin, TX
Nelson P. Daly, DDS, FAGD
Baton Rouge, LA
Carl H. Boykin, DDS, MAGD
Jackson, MS
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Atlanta, GA
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Canaan, NH
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Woodland Hills, CA
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Mount Pleasant, SC
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League City, TX
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Denville, NJ
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Lancaster, CA
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Berwyn, PA
Tim L. Goodheart, DDS, FAGD
Raytown, MO
Cody C. Graves, DDS, FAGD
Goldthwaite, TX
Scott E. Gray, DDS, ABGD, FAGD
Englewood, OH
Janiene F. Gresla, DDS, FAGD
Burlington, MA
Jiafeng Gu, MD, PhD
New York, NY
Mitchell M. Guess, DMD, MAGD
Hattiesburg, MS
Harish Gulati
Boston, MA
Jeffery W. Hadley, DDS, FAGD
Henderson, NV
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Thornhill, ON, Canada
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Columbus, OH
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Granbury, TX
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Pikesville, MD
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Westford, MA
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Vancouver, WA
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Elmsford, NY
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Smithtown, NY
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San Diego, CA
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Sugar Grove, IL
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Ocean Springs, MS
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Lake Villa, IL
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Langley, BC, Canada
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Naples, FL
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Springville, CA
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Layton, UT
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Chapel Hill, NC
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Denison, TX
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Houston, TX
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Littleton, MA
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McClellan, CA
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Wylie, TX
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Turners Falls, MA
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Philadelphia, PA
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Fontana, CA
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Keystone Heights, FL
Harish Koratkar, BDS, FAGD
Hopkins, MN
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Fernandina Beach, FL
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Brooklyn, NY
Jerry M. Strauss, DMD, MAGD
Fairfield, NJ
Lawrence Kotlow, DDS
Albany, NY
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Malone, WI
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Udaipur, Rajasthan, India
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Dallas, TX
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Silver Spring, MD
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Ocala, FL
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Dubuque, IA
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Augusta, GA
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Augusta, GA
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Philadelphia, PA
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Tunkhannock, PA
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General Dentistry
March/April 2011
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Fixed Prosthodontics
Management of the severely worn
dentition with different prosthetic
rehabilitation methods: A case series
Emre Mumcu, DDS, PhD
n
Onur Geckili, DDS, PhD
n
Hakan Bilhan, DDS, PhD
Clinicians are often faced with the challenge of restoring a severely
worn dentition. Esthetic and functional rehabilitation of patients in
this condition represents a noteworthy clinical challenge. Although
treatment options for the severely worn dentition with reduced
occlusal vertical dimension can be limited, providing a functional
T
ooth wear has been described
as the loss of tooth substance
resulting from abrasion,
attrition, erosion, or abfraction.1
Abrasion is the loss of tooth
surface caused by friction from
foreign substances other than
tooth-to-tooth contact.2 Attrition
is tooth wear caused by the
rubbing together of opposing
occlusal surfaces of teeth during
mastication or parafunction.2,3
Erosion (corrosion) indicates the
progressive loss of tooth structure
through nonbacteriogenic
chemical processes.1 Abfraction
is the pathologic loss of tooth
structure attributed to mechanical
loading, resulting in noncarious
cervical lesions.1,2
Etiologic factors also include diet,
gastroesophageal disease, eating
disorders, bruxism, harmful oral
habits, and congenital anomalies
such as amelogenesis imperfecta
and dentinogenesis imperfecta.1,2,4
Although some degree of tooth
wear is acknowledged as a normal
part of the aging process, known
as physiologic wear, problems arise
when the normal rate of tooth wear
is accelerated by unusual endogenous or exogenous factors.1,2
n
Tolga Kayserili, DDS, PhD
and esthetic restoration in these situations is crucial for restoring
the patient’s quality of life. Different treatment approaches for the
rehabilitation of worn dentition are presented in this case series.
Received: January 12, 2010
Accepted: April 26, 2010
Prior to treating tooth wear, it is
crucial to determine the causes and
to try to eliminate them following
treatment.1,2 It is often believed that
tooth wear is the result of bruxism,
although other etiologic factors may
be involved.2 Clinicians must fully
understand other possible causes
of wear and how the appearance of
the dentition may differ according
to the cause of wear.2 For example,
wear caused by attrition is located
only in occlusal contact areas.
Facial or lingual surfaces of teeth
are affected only if opposing teeth
are in contact in these areas during
excursive movements. Also, a similar
amount of tooth wear is visible in
both arches.1,2
Erosion or corrosion can occur as
the result of endogenous sources,
such as bulimia or gastroesophageal reflux disease, or exogenous
sources, such as acidic beverages,
citrus-sucking habits, and the use
of amphetamine drugs, chewable
vitamin C tablets, or aspirin.1,2,4
Corroded tooth surfaces have
imprecise extensions, unlike
attrition lesions.2 Bulimia affects
the palatal surfaces of maxillary
anterior teeth and also can affect
the buccal surfaces of posterior
www.agd.org
teeth.1 Citrus sucking affects the
labial and palatal surfaces of the
maxillary incisors, increasing the
translucency and sharpness of these
teeth.1,2 Old amalgam restorations
could begin to protrude from posterior teeth.1
Abrasion can occur as a result of
gritty foods, abrasive tooth polishes,
improper usage of toothbrushes
and toothpicks, damaging oral
habits such as tobacco chewing and
pencil or nail biting, or clasps of
removable dentures; it also can be
an occupational hazard for tailors
and shoemakers.1,4 Abrasion from
food results in worn occlusal areas
without outlined borders. A general
rounding effect, microscopic pits,
or scratches are visible on tooth
surfaces.4 Also, cervical wedgeshaped lesions are noticeable from
toothbrush strokes.
Abfraction can be seen primarily
in the cervical region of teeth. To
differentiate abfraction from abrasion, the reasons for occurrence
should be considered. Abfraction
lesions occur from the loading
forces placed on teeth during
static events, such as swallowing or
clenching, or cyclic events, such as
chewing or bruxing.1
General Dentistry
March/April 2011
e41
Fixed Prosthodontics Management of the severely worn dentition with different prosthetic rehabilitation methods
Fig. 1. Intraoral view of worn maxillary teeth.
Fig. 2. Mandibular removable partial denture with worn artificial teeth.
Fig. 3. Intraoral view of the cast metal post-and-core restorations after
cementation.
Fig. 4. Final view of the metal-ceramic crowns.
Fig. 5. Post-treatment view of the removable
partial denture.
A differential diagnosis is not
always possible because more than
two mechanisms may be involved
in the etiology of tooth wear.1,2,4
Once the clinician has developed
e42
March/April 2011
a complete understanding of the
etiology, a treatment plan can be
formulated. The number of teeth
to be treated, condylar position,
space availability, vertical dimension of occlusion (VDO), and the
choice of restorative material must
be considered.4,5
Before starting any restorative
treatment, an initial interview—
including a detailed review of the
patient’s medical and dental history,
a discussion of the patient’s usual
diet, and an evaluation of potential
work-related factors and detrimental
oral habits—should be conducted.1,2
The clinical examination should
include observation of specific wear
patterns and VDO using previously
described techniques.5-7 Loss of
tooth structure does not necessarily
mean loss of VDO; in fact, it may
General Dentistry
www.agd.org
be difficult to determine if the VDO
has been lost. Several aspects such as
loss of posterior support, history of
wear, phonetic evaluation, interocclusal distance, and facial appearance should be examined carefully.1,4
The clinical examination can be
enhanced with the use of stone
study casts, intraoral photographs,
radiographs, and salivary tests.1
In situations where loss of tooth
structure has occurred and the
VDO is still acceptable, treatment
may include crown lengthening,
orthodontic movement with limited
intrusion, and surgical repositioning
of a segment of teeth and supporting
alveolar bone. Whenever the clinical
evaluation demonstrates the necessity
to restore the VDO, a trial period
with removable occlusal splints can
be followed by crown placement and
Fig. 7. Final view of the patient after the cementation of metal-ceramic
crowns.
Fig. 6. View of the generalized worn dentititon.
fixed partial dentures or cast overlay
removable partial dentures.1 In definitive rehabilitation, the final choice of
treatment depends on the condition
of the patient’s remaining teeth.1
The following case series presents
different prosthetic management
options for the treatment of a worn
dentition.
Case reports
Case report No. 1
A 63-year-old man came to the
clinic with severely worn teeth and
generalized hypersensitivity (Fig. 1).
There were no significant findings
in the patient’s medical history. Possible causes of tooth wear had been
evaluated and conversation with the
patient revealed a grinding habit and
a high consumption of acidic drinks.
His dental history included no
treatment of the maxillary teeth and
restoration of the mandibular edentulous region with four porcelain
crowns and a mandibular removable
denture with precision attachments.
Clinical examination revealed generalized worn dentition in the maxillary and mandibular anterior regions
as well as worn artificial teeth on
the mandibular removable denture
(Fig. 2). It was determined that the
3.0–4.0 mm loss of VDO was caused
by a combination of attrition and
erosion. Clinical examination was
improved with the use of stone
study casts, intraoral photographs,
and periapical radiographs. Since
the optimal VDO was lost, the
task of rehabilitation was easier to
accomplish, because the dimension
could be regained without surgical or
orthodontic interventions.
Maxillary anterior teeth were
treated endodontically and restored
with cast metal post-and-core
restorations for extending the VDO
(Fig. 3). The provisional restorations
were fabricated according to the
increased VDO and were temporarily cemented. Since the masticatory
muscles and the temporomandibular joint showed no clinical signs
or symptoms of discomfort during
this period, the definitive metalceramic crowns were fabricated and
cemented using a polycarboxylate
cement (Poly-F Plus, Dentsply
DeTrey GmbH) (Fig. 4). Simultaneously, the worn artificial teeth of
the mandibular partial denture were
replaced with new ones (Fig. 5).
To protect the restorations, an
occlusal splint was created and used.
Follow-up one year later revealed no
complications with the prosthesis
and excellent patient satisfaction.
Case report No. 2
A 56-year-old man was referred
to the clinic with a severely worn
www.agd.org
dentition. Conversation with the
patient revealed gastroesophageal
reflux disease and a nail-biting
habit. Clinical examination revealed
generalized severely worn maxillary
and mandibular teeth (Fig. 6).
Preliminary impressions
were made with an irreversible
hydrocolloid impression material
(Xantalgin, Heraeus Dental North
America), and the maxillomandibular relationship was transferred into
a semi-adjustable articulator (ARTI
S4, IML Instrument Mechanic
Lab, Inc.) using a facebow transfer
for estimating a suitable treatment option. An acrylic maxillary
occlusal splint was constructed at a
4.0 mm increase of VDO to assess
the patient’s adaptation to a reorganized occlusal scheme. After three
months of adaptation to the new
VDO, all teeth were prepared and
restored with metal-on-porcelain
crowns (Fig. 7).
Case report No. 3
A 58-year-old woman with a severely
worn dentition came to the clinic
expressing the desire to have her
teeth restored for reasons of function, dental hypersensitivity, and
esthetics. The patient’s medical and
dental histories were recorded and
radiographs were taken. A history
of nocturnal and diurnal bruxism
General Dentistry
March/April 2011
e43
Fixed Prosthodontics Management of the severely worn dentition with different prosthetic rehabilitation methods
Fig. 8. View of the reduced VDO due to worn teeth.
was reported. Intraoral examination
revealed a loss of dental structure,
especially from the maxillary first
and second incisors, and several
missing teeth, both in the maxilla
and mandible (Fig. 8). The patient
had lost her teeth approximately 12
years earlier and had not worn any
prosthesis since that time. Clinical
determination of VDO was achieved
using the same method from case
report No. 1, and a 3.0 mm loss of
VDO was determined, depending
on the loss of posterior support.
Impressions were made for
diagnostic examination with an
irreversible hydrocolloid (Xantalgin), and stone models were
Fig. 9. Final view of the patient after increasing the VDO.
mounted to a semi-adjustable
articulator with occlusal records
and a facebow transfer (ARTI S4)
of the patient. The occlusal scheme
was reorganized using bimaxillary
acrylic occlusal splints. Bilateral and
simultaneous contact of all posterior teeth was achieved using these
acrylic occlusal splints. Because
there were no signs or symptoms
of discomfort after a three-month
trial period, the existing teeth were
restored with metal-ceramic crowns,
while the plan was to replace the
missing posterior teeth in both
arches with removable partial dentures with precision attachments.
All maxillary and mandibular teeth
Fig. 10. Initial view of a patient with worn teeth.
e44
March/April 2011
General Dentistry
www.agd.org
were prepared by guidance of the
occlusal splints.
Metal-ceramic restorations were
fabricated in accordance with the
increased VDO. After the removable partial denture was fabricated,
the fixed segment was cemented.
Centric occlusion, protrusive
contacts, and canine guidance
were established in the definitive
restorations (Fig. 9). The patient
was satisfied and the recall evaluation six months later showed no
complications.
Case report No. 4
A 36-year-old woman came to
the clinic with generalized worn
dentition (Fig. 10). Similar to case
reports No. 2 and 3, the VDO
had to be increased and tested for
several months; a removable overlay
denture was fabricated for this
purpose (Fig. 11 and 12). The use
of such a denture provides several
advantages, such as better function
and better esthetic estimation of
the final rehabilitation outcome.
Because the loss of tooth substance
occurred primarily in the mandible,
the plan was to increase the VDO
using a mandibular provisional
overlay denture. Another advantage
of this treatment modality is a
longer adaptation period for the
Fig. 11. View of the removable overlay denture.
patient established via restored
esthetics and function.
Discussion
Reconstruction of the severely
worn dentition can create a challenge for clinicians. The best
treatment for any wear depends
on early recognition of the wear,
but it can be difficult and even
impossible to do this.1,2 All four
cases presented here had severe
worn dentition situations requiring
full-mouth rehabilitation with a
need to increase the VDO. If an
increase in VDO is indicated and
performed, the patient should
return for a follow-up visit in
several months.4 In all cases, diagnostic evaluations were made on
semi-adjustable articulators, and
provisional restorations or occlusal
splints were used for the adaptation of the musculoskeletal system
before the definitive restorations
were delivered. Despite warning
against increasing the VDO, evi-
Fig. 12. Intraoral view of the overlay denture.
dence from long-term observations
supports the view that, in general,
the patient will adapt to such an
increase and that the new VDO is
stable.4,6,7 Determining and eliminating factors causing tooth wear
is critical in long-term preservation
of the new VDO and restorations.
Inserting an occlusal splint in a
patient with a history of bruxism
appears to be essential to protect
the restorations.
Summary
In this case series, satisfactory and
stable clinical results were obtained
by restoring the VDO, with drastic
improvement in esthetics and function justifying the procedures used.
Author information
Drs. Mumcu, Geckili, and Bilhan
are research assistants, Faculty of
Dentistry, Department of Prosthodontics, Istanbul University,
Istanbul, Turkey. Dr. Kayserili is in
private practice in Istanbul.
References
1. Grippo JO, Simring M, Schreiner S. Attrition,
abrasion, corrosion and abfraction revisited: A
new perspective on tooth surface lesions. J Am
Dent Assoc 2004;135(8):1109-1118.
2. Spear F. A patient with severe wear on the anterior teeth and minimal wear on the posterior
teeth. J Am Dent Assoc 2008;139(10):13991403.
3. The glossary of prosthodontic terms. J Prosthet
Dent 2005;94(1):10-92.
4. Larson TD. Tooth wear: When to treat, why, and
how. Part one. Northwest Dent 2009;88(5):3138.
5. Prasad S, Kuracina J, Monaco EA Jr. Altering occlusal vertical dimension provisonally with base
metal onlays: A clinical report. J Prosthet Dent
2008;100(5):338-342.
6. Spear FM. Approaches to vertical dimension.
Adv Esthet Interdiscip Dent 2006;2(3):2-12.
7. Dawson PE. Functional occlusion: From TMJ to
smile design. St. Louis: Mosby;2006:432-433.
Manufacturers
Dentsply DeTrey GmbH, Konstanz, Germany
49.07531.5830, www.dentsply.de
Heraeus Dental North America, South Bend, IN
800.431.1785, heraeus-dental-us.com
IML Instrument Mechanic Lab, Inc., Kennesaw, GA
800.815.2389,
www.iml.de/shopeng10/dental-care/index.html
COMMENT
www.agd.org
General Dentistry
March/April 2011
e45
substance Abuse
Opiate overdose in an adolescent after
a dental procedure: A case report
James Hawthorne, MD
Catherine Martin, MD
n
Pamela Stein, DMD, MPH
n
Madeline Aulisio
Oxycodone/acetaminophen is a combination of acetaminophen
and the opiate oxycodone. It is an effective analgesic that is
commonly prescribed postoperatively. The potential for misuse,
diversion, abuse, and overdose with opiates in general is an area
of increasing concern to all prescribing clinicians. This case report
illustrates the possibility of a severe or potentially fatal outcome
A
16-year-old boy came to
an outpatient universitybased psychiatric office,
accompanied by his parents. The
reason for his referral was a recent
suicide attempt by overdose:
Approximately three months earlier
he had attempted suicide by taking
approximately 30 Percocet tablets
of unknown strength and was
hospitalized in an inpatient child
and adolescent psychiatric ward for
four days.
The patient said that four months
prior to this visit, his wisdom teeth
were removed and he subsequently
was prescribed oxycodone/acetaminophen (Percocet). He began
taking the Percocet as prescribed,
but, over time, he developed the
habit of taking two or three tablets
per week, as these helped him to
cope with stresses he encountered
in school. These stresses included
falling behind on assignments,
being caught cheating on his
homework, his perception of
parental pressure to succeed, and
peer pressure to use drugs. He
soon needed more Percocet, so he
accessed his mother’s and grandfather’s prescriptions, taking them
for his own usage.
e46
March/April 2011
n
Laurie Humphries, MD
to a common prescribing practice. Caution is emphasized when
prescribing opiates, and screening for substance misuse and suicide
risk factors is recommended.
Received: March 1, 2010
Accepted: April 27, 2010
This pattern continued for
approximately one month until the
stresses from school became too
great and the patient attempted
suicide as described above. His
reasons for the suicide attempt
included exacerbation of pressure
from school and perceived parental
pressure to succeed. He did not
overtly tell anyone of his intentions,
although he sent a text message to a
friend that was indicative of suicide
intent. The friend informed her
father, who contacted the patient’s
parents, who rushed him to the
local emergency room.
The patient was medically cleared,
and psychiatric admission to the
adolescent unit followed. During
this admission he was diagnosed
with obsessive-compulsive disorder,
depression, and opiate abuse; was
prescribed fluoxetine (Prozac) 10
mg; and was subsequently discharged home, with follow-up to be
made at the outpatient clinic. Upon
arrival at the clinic, the patient was
judged to be suffering from clinical
depression and his obsessive-compulsive symptoms were improved.
He also was no longer misusing opiates. The fluoxetine was continued,
and the possibility of increasing the
General Dentistry
www.agd.org
dosage was discussed. The patient
was referred to a psychologist for
psychological testing, and continuance of therapy was encouraged.
The patient had no previous history of psychiatric diagnoses. His
early development and growth were
unremarkable. His medical history
included acne treated with isotretinoin (Accutane) and premature
male pattern baldness, which caused
him significant emotional distress.
The patient lived at home with his
biological parents, ages 44 and 43,
and two younger sisters, ages 6 and
14. He attended a local high school,
where his grades were mostly Bs,
struggling particularly in reading
and writing. He had multiple friends
at school, none of whom used drugs.
He described himself as a perfectionist and felt that this contributed to
his stress at school. Significant family
psychiatric history included a greatgrandfather and great-uncle who
committed suicide; a grandfather
with treatment-resistant depression;
a first cousin with depression and
ADHD; and multiple family members with alcohol dependence.
Referral for psychological testing
showed the patient to be a student
of average intelligence (107 on
the WAIS-III) who likely would
perform poorly on repetitious tasks
under a time pressure. Overall,
his scholastic abilities were on a
level comparable to those of his
classmates. However, he scored
significantly lower in the areas of
reading comprehension, writing,
and the application of instructions.
These deficiencies were in the face of
above-average school performance
that suggested significant overachieving on his part, which may
have contributed to the stresses that
he experienced.
Discussion
This case illustrates many issues
of concern to any clinician who
prescribes opiates to adolescent
patients, including adolescent
suicide risk, the misuse and diversion of opiates, and undiagnosed
psychiatric illness.
Suicide is the third leading cause
of death among adolescents in the
United States, with rates beginning
to rise after the onset of puberty
and stabilizing in early adulthood.1,2
Annually, the two suicide methods
that adolescents use most commonly are suffocation (including
hanging) and firearms.3 Intentional
self-poisoning, such as in this case
report, is the third most-commonly
used method by adolescents,
accounting for 5% of all adolescent
suicides in the U.S. in 2006.3
Predicting which patients are at
risk for suicide can be approached
through the evaluation of risk
factors, which include substance
misuse; previous suicide attempts;
psychiatric illness; family history
of depression and suicide; current
stressors; recent loss; hopelessness;
history of abuse; and exposure to
adolescent suicides.2,4 The patient
demonstrated several of these known
risk factors for suicide prior to
being prescribed Percocet, including
stress at school, depression, anxiety,
and an extensive family history of
depression and suicide. He also
took the acne medication Accutane,
which has been linked anecdotally
to depression and suicidal behavior
in teens, although no clear causative
link has been established.5
In addition to these pre-existing
risk factors for suicide, the patient
began to misuse prescription opiates as a form of self-medication
for his depression and anxiety.
This substance misuse was another
risk factor in his eventual suicide
attempt.6 This case demonstrates the
importance of screening adolescents
for undiagnosed depression as well
as suicide risk factors prior to the
prescription of opiates.
Misuse and diversion of prescription opiates is another area of concern demonstrated in this case, as
the patient’s misuse of prescription
opiates contributed to his eventual
suicide attempt. Over the last
decade, the steadily rising number
of annual prescriptions for opiates
has contributed to increased access
to these medications.7 Currently, the
U.S. is the world leader in opiate
consumption, using 80% of all opiates and 99% of the world’s supply
of hydrocodone.8 The increasing
access to opiate medications has
been a factor in the rising rates
of misuse and diversion of these
substances by adolescents.9 Prescription medications now constitute the
fastest-growing group of substances
being misused by adolescents.10
Predicting which patients will
misuse prescription medications can
be difficult; however, the evaluation
of psychosocial risk factors can help
to stratify patients based on risk of
misuse. Poor school performance,
depression during the past year, high
levels of risk taking, and the use of
other substances are highly correlated with the misuse of prescription
www.agd.org
medications.11 The patient in this
case reported two of these risk
factors: unsatisfactory school performance and depression.
The importance of identifying
patients at risk for substance misuse
and suicide is well-illustrated in the
case described here. The patient had
been suffering from undiagnosed
depression and anxiety, which
he attempted to self-medicate by
misusing prescription opiates. These
undiagnosed psychiatric conditions,
his substance misuse, the growing
stress at school, and easy access to
opiates both through his recent prescription and the presence of unused
opiates in the household ultimately
contributed to his suicide attempt.
What role do prescribing clinicians have in identifying mental
illness and hopefully decreasing the
chance of the sequence of events
seen in the case presented here?
Dentists and oral surgeons are
increasingly involved in preventive
screening; for example, they often
are the first clinicians to identify
tobacco use. The evaluation of
substance misuse and suicide risk
factors is another area of preventive
screening that should be completed
prior to prescribing a substance with
both abuse liability and potential
lethality. This evaluation could consist of a short questionnaire, completed by the patient, which would
stratify patients based on risk factors
for substance misuse and suicide.
The authors have compiled a short
questionnaire that is specifically
targeted to evaluate known suicide
and substance misuse risk factors
in adolescents. This screening tool
(Fig. 1) can be customized to meet
the needs of the prescribing clinician. Adolescent patients should be
told that the results of the questionnaire are confidential except when
it is determined that the patient is
reporting suicide intent. In these
General Dentistry
March/April 2011
e47
substance Abuse Opiate overdose in an adolescent after a dental procedure
This questionnaire should be completed by you, the patient.
Please select the answer which most applies to you.
1. ❑ Male
❑ Female
2. How old are you? __________________________________________________
3. What grade are you in? ______________________________________________
4. Are your grades:
❑ improving
❑ staying the same
❑ getting worse
❑ yes
5. Do you have a lot of stress at school or home?
❑ no
6. Do you smoke cigarettes?
❑ yes
❑ no
7. Do you use smokeless tobacco (dip or chew)?
❑ yes
❑ no
8. Have you had any trouble with the law?
❑ yes
❑ no
9. Have you ever had thoughts of killing yourself?
❑ yes
❑ no
10. Have you tried to kill yourself?
❑ yes
❑ no
11. Do you know anyone your age who has killed themselves?
❑ yes
❑ no
12. Has anyone in your family killed themselves?
❑ yes
❑ no
13. Do you feel hopeless?
❑ yes
❑ no
14. Have you recently lost someone you love?
❑ yes
❑ no
1 5. Have you ever been abused by anyone?
❑ yes
❑ no
❑ yes
❑ no
a. ❑ physically
b. ❑ sexually
c. ❑ emotionally
16. Do you feel sad most of the time?
17. Do you see a mental health professional?
❑ yes
❑ no
18. Do you drink alcohol?
❑ yes
❑ no
❑ yes
❑ no
19. Have you ever used drugs?
a. Marijuana
b. Cocaine
❑ yes
❑ no
c. Meth
❑ yes
❑ no
d. LSD, PCP
❑ yes
❑ no
e. Huffed/sniffed
❑ yes
❑ no
❑ yes
❑ no
20. Have you ever used someone else’s prescription medicine?
If so, what medication was it? _________________________________________
Fig. 1. Treating with opiates: Adolescent screening test (TOAST).
cases, the dentist or oral surgeon
will review the concerns with the
patient and share them with his or
her guardian to ensure the patient’s
safety. If an adolescent patient
reports being abused, this must
also be reported to the appropriate
authorities. In all cases, the patient’s
safety must be a priority.
e48
March/April 2011
Prescribing practices could be
altered based on the results of
the questionnaire. Options could
include changing the analgesic class
to an NSAID or acetaminophen
if serious safety concerns become
apparent through the screening
and follow-up questioning.12,13
If needed, opiates could still be
General Dentistry
www.agd.org
used judiciously, ensuring parental
monitoring of medication and
prescribing only the necessary
amount. When a patient is deemed
to be at risk for suicide, appropriate
steps should be taken to ensure
patient safety, including parental
monitoring and referral to a trusted
colleague for psychiatric evaluation
and treatment.
Summary
Prescription opiates are increasingly
being misused by adolescents, and
caution should be exercised when
prescribing these medicines. Special
consideration should be given to
undiagnosed psychiatric illness and
suicide potential. Clinicians should
consider using a screening tool that
would identify adolescents at risk
for suicide as well as the development of substance misuse. This
questionnaire (or some variation)
could be integrated into routine
screening questions administered
prior to most adolescent dental
appointments, especially those at
which opiates might be prescribed.
Author information
Dr. Hawthorne is a first-year
psychiatry resident, University of
Kentucky College of Medicine, Lexington, where Dr. Stein has recently
retired as an associate professor,
Department of Anatomy and Neurobiology; Dr. Humphries is professor emeritus of psychiatry; and Dr.
Martin is a professor and director
of the Child Division, Department
of Psychiatry. Ms. Aulisio is a recent
graduate in psychology, Transylvania
University, Lexington, KY.
References
1. Hoyert DL, Kung HC, Smith BL. Deaths: Prelimary data for 2003. Natl Vital Stat Reports 2005;
53(15):1-48.
2. Spirito A, Esposito-Smythers C. Attempted and
completed suicide in adolescence. Annu Rev
Clin Psychol 2006;2:237-266.
3. Web-based inquiry statistics query and reporting system (WISQARS). Available at www.cdc.
gov/injury/wisqars/index.html. Accessed November 17, 2010.
4. Kim CD, Seguin M, Therrien N, Riopel G, Chawky
N, Lesage AD, Turecki G. Familial aggregation of
suicidal behavior: A family study of male suicide
completers from the general population. Am J
Psychiatry 2005;162(5):1017-1019.
5. O’Reilly K, Bailey SJ, Lane MA. Retinoid-mediated regulation of mood: Possible cellular mechanisms. Exper Biol Med 2008;233(3):251-258.
6. Fleischmann A, Bertolote JM, Belfer M, Beautrais A. Completed suicide and psychiatric diagnoses in young people: A critical examination of
the evidence. Am J Orthopsychiatry 2005;75(4):
676-683.
7. Zerzan JT, Morden NE, Soumerai S, Ross-Degnan
D, Roughead E, Zhang F, Simoni-Wastila L, Sullivan S. Trends and geographic variation of opiate
medication use in state Medicaid fee-for-service
programs, 1996 to 2002. Med Care 2006;
44(11):1005-1010.
8. Manchikanti L, Singh A. Therapeutic opioids: A
ten-year perspective on the complexities and
complications of the escalating use, abuse, and
nonmedical use of opioids. Pain Physician 2008;
11(2 Suppl):S63-S88.
9. Compton WM, Volkow ND. Major increases in
opioid analgesic abuse in the United States:
Concerns and strategies. Drug Alcohol Depend
2006;81(2):103-107.
10. Rogers PD, Copley L. The nonmedical use of prescription drugs by adolescents. Adolesc Med
State Art Rev 2009;20(1):1-8.
11. Schepis TS, Krishnan-Sarin S. Characterizing adolescent prescription misusers: A populationbased study. J Am Acad Child Adolesc Psychiatry
2008;47(7):745-754.
12. Ong CK, Lirk P, Tan CH, Seymour RA. An evidence-based update on nonsteroidal anti-inflammatory drugs. Clin Med Res 2007;5(1):
19-34.
13. Moller PL, Juhl GI, Payen-Champenois C, Skoglund LA. Intravenous acetaminophen (paracetamol): Comparable analgesic efficacy, but
better local safety than its prodrug, propacetamol, for postoperative pain after third molar
surgery. Anesthes Analg 2005;101(1):90-96.
COMMENT
www.agd.org
General Dentistry
March/April 2011
e49
Dental Materials
Gradual surface degradation of restorative
materials by acidic agents
Chanothai Hengtrakool, DDS, MSc, PhD
n
Boonlert Kukiattrakoon, DDS, MSc
The aim of this study was to investigate the effect of
acidic agents on surface roughness and characteristics of four
restorative materials. Fifty-two discs were created from each
restorative material: metal-reinforced glass ionomer cement
(Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin
composite (Filtek Z250), and amalgam (Valiant-PhD); each disc
was 12 mm in diameter and 2.5 mm thick. The specimens were
divided into four subgroups ( n = 13) and immersed for 168 hours
in four storage media: deionized water (control); citrate buffer
solution; green mango juice; and pineapple juice. Surface roughness measurements were performed with a profilometer, both
before and after storage media immersion. Surface characteristics
were examined using scanning electron microscopy (SEM).
R
estorative treatment is necessary when a patient suffers
tooth surface loss, which is a
functional loss of dental hard tissue
and commonly includes an unacceptable change in esthetics, dentin
hypersensitivity, and, in severe cases,
pulpal exposure.1,2 A suitable restoration may be required to restore
the affected tooth. These materials
should achieve an intimate adaptation with cavity interfaces to best
resist microleakage and the influx
of oral irritants. In other words, the
materials used would not lead to
postoperative sensitivity, interfacial
staining, or recurrent caries.
Currently, several different restorative materials are recommended for
tooth surface loss lesions, including
glass ionomer cement, reinforced
glass ionomer cement, resin-modified
glass ionomer cement, composite
resin, and amalgam.3 The advantages
and disadvantages of each material’s
properties should be considered prior
to choosing it for the restoration.
e50
March/April 2011
n
Statistical significance among each group was analyzed using
two-way repeated ANOVA and Tukey’s tests.
Ketac-S demonstrated the highest roughness changes after
immersion in acidic agents ( p < 0.05), followed by Fuji II LC.
Valiant-PhD and Filtek Z250 illustrated some minor changes over
168 hours. The mango juice produced the greatest degradation
effect of all materials tested ( p < 0.05). SEM photographs
demonstrated gradual surface changes of all materials tested
after immersions. Of the materials evaluated, amalgam and resin
composite may be the most suitable for restorations for patients
with tooth surface loss.
Received: October 22, 2009
Accepted: February 15, 2010
Composite resin is a mixture
of polymers or resins and glass
particles or fillers.4 This material
bonds to the tooth structure and
can provide an acceptable esthetic
result. However, it is not as effective
for the restoration of large, defective
posterior teeth.
Glass ionomer cement is composed mainly of calcium fluoroaluminosilicate glass in the powder,
which reacts with the aqueous
polyacrylic acid or related polymeric
acid.5 It is especially effective for
treating erosion lesions because of its
potential to release fluoride ions into
the underlying dentin to protect the
tooth structure; however, glass ionomer cement is susceptible to fracture
and exhibits low wear resistance.6
Development of the glass ionomer
cement brought about cermet
(ceramic-metal) cement, where
glass and silver are fused together.7
The silver particles improve some
mechanical properties of the cement
and increase their resistance.8,9
General Dentistry
Ureporn Kedjarune-Leggat, DDS, PhD
www.agd.org
In the recently introduced resinmodified glass-ionomer cements,
polyacids in a conventional glass
ionomer cement are modified with
a pendant methacrylate group.10 As
a result, it has been claimed that
the mechanical properties of glass
ionomer cement were improved.11,12
However, some clinicians believe that
resin-modified glass ionomer cement
should be used with caution on the
occlusal surface, as it has a high rate
of degradation compared with resin
composite and amalgam.4,13
Finally, amalgam has been used
for restorations for a long time
(nearly 200 years). It is an alloy
that results from the reaction of
the ions of silver, tin, and copper
acting with mercury.13 Amalgam
has positive physical properties for
posterior teeth restoration; however,
it requires retention and resistance
cavity formation for the restoration.
The long-term clinical service of
restorative materials depends on
their physical characteristics. One
Table 1. Restorative materials investigated in this study.
Product
Type of material
Main constituents
Mixing
Batch No.
Manufacturer
Ketac-S
Metal-reinforced glass
ionomer cement
Silver (40% w/w)
Capsulated
139517
3M ESPE
Fuji II LC
Resin-modified glass
ionomer cement
Resin-modified polyacrylic
acid, ion leachable glass
Hand-mixed (3:1 P/L)
0202271
GC America Inc.
Filtek Z250
Composite resin
Bis-GMA, zirconia/silica fillers
One-paste
20021127
3M ESPE
Valiant-PhD
Amalgam
Silver, tin, copper, palladium,
mercury
Capsulated
020913
Dentsply Caulk
Bis-GMA: 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane.
of the most important physical
properties is surface roughness.14
The presence of roughness or
surface irregularities could affect
esthetics, plaque retention,
discoloration, and gingival inflammation.15-17 Previous studies have
indicated that some chemicals and
acidic foods, particularly acidic
beverages, can cause surface degradation of not only the tooth but
also the restorative materials.12,18-23
Beverages tested in previous studies have included carbonated soft
drinks and orange and apple juices,
which contain phosphoric and carbonic acids, citric acid, and malic
acid, respectively.12,20,23-26
Generally, the behavior of eating
and chewing sour fruits, such as
green mangoes, pineapples, and
limes, is most commonly found in
tropical countries such as Australia,
New Zealand, Cuba, and countries
in southeast Asia.27-30 A study in
southern Thailand showed the
associated factors of tooth wear
to include age, gender, number of
teeth lost, frequency of alcohol consumption, and carbonated drinking
and sour fruit intake.30
Even though previous studies have reported that certain
beverages and fruit juices, such as
carbonated soft drinks and orange
and apple juices, have a softening
Table 2. Surface roughness parameters used and their meanings.
Roughness
parameter
Meanings
Ra
The arithmetical average of surface heights
Rmax
The magnitude of the peak-to-valley height in all cutoff lengths
Rz
The average height difference between the 10 highest peaks and 10 lowest
valleys within each cutoff length
Sm
The arithmetical average spacing between peaks at the mean line over
the cutoff length
effect on restorative materials, sour
fruits, such as green mangoes and
pineapples, may have an effect as
well. Unfortunately, little is known
about the effect of eating these sour
fruits on restorative materials. The
purpose of this in vitro study was to
investigate the erosive potential of
acidic agents (sour fruit juices) on
the surface roughness and characteristics of four restorative materials
(metal-reinforced glass ionomer
cement, resin-modified glass ionomer cement, resin composite, and
amalgam). The hypothesis was that
the acidic agents under investigation
would cause significant changes in
surface roughness of the restorative
materials evaluated.
Materials and methods
Four types of restorative materials
were selected for this study: a metal-
www.agd.org
reinforced glass ionomer cement
(Ketac Silver Aplicap [Ketac-S]);
a resin-modified glass ionomer
cement (Fuji II LC); a composite
resin (Filtek Z250); and amalgam
(Valiant-PhD) (see Table 1). Fuji
II LC supplied as a powder/liquid
type was used as the hand-mixing
material. The powder/liquid ratio
used was 1.0 g to 0.3 mL. Ketac-S
and Valiant-PhD were supplied as
preloaded capsules and were mixed
using an electrical amalgamator
at 4,300 Hz (ProMix, Dentsply
International) for 10 seconds.
Fuji II LC and Filtek Z250 were
polymerized for 40 seconds with
a photoactivated polymerization
unit. The light intensity was verified
with a measuring device (Cure Rite,
Dentsply Caulk).
Fifty-two disc specimens of each
restorative material were made using
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e51
Dental Materials Gradual surface degradation of restorative materials by acidic agents
Table 3. Means and standard deviations of roughness parameters (R a , R max , R z, and S m) of Ketac-S immersed in
various storage media for different intervals.
Time (hours)
Roughness
parameters
Storage media
1
6
24
48
72
96
168
Ra (µm)
Deionized water
0.02
± 0.01
0.02
± 0.01
0.01
± 0.01
0.02
± 0.01
0.01
± 0.01
0.02
± 0.01
0.02c
± 0.01
Citrate buffer
0.01
± 0.01
2.40*
± 0.51
3.13*
± 1.25
4.47*
± 0.64
5.87*
± 0.92
7.13*
± 1.28
7.67*,b
± 1.63
Mango juice
0.02
± 0.01
3.40*
± 0.63
8.80*
± 1.74
9.20*
± 0.77
9.20*
± 1.74
11.87*
± 1.22
12.07*,a
± 1.98
Pineapple juice
0.02
± 0.01
0.05
± 0.02
2.47*
± 0.52
3.13*
± 0.74
4.07*
± 1.03
4.20*
± 1.15
6.93*,b
± 1.39
Deionized water
7.73
± 0.96
7.73
± 1.96
7.67
± 1.89
7.80
± 2.57
7.93
± 2.63
7.73
± 2.68
8.13d
± 2.23
Citrate buffer
7.60
± 0.99
29.07*
± 8.69
54.67*
± 12.96
100.07*
± 16.67
144.93*
± 10.97
213.33*
± 19.98
281.4*,b
± 35.05
Mango juice
7.40
± 2.03
45.47*
± 12.58
153.80*
± 18.55
210.93*
± 47.67
244.20*
± 40.58
246.53*
± 37.72
314.4*,a
± 57.4
Pineapple juice
6.80
± 1.32
12.07*
± 1.44
35.93*
± 9.65
50.27*
± 7.43
75.6*
± 17.48
83.87*
± 10.56
142.8*,c
± 26.34
Deionized water
3.40
± 0.51
3.40
± 0.91
3.33
± 0.98
3.46
± 0.52
3.40
± 0.51
3.33
± 0.89
3.40c
± 0.83
Citrate buffer
3.47
± 0.52
19.73*
± 5.22
21.13*
± 6.92
32.20*
± 5.47
42.33*
± 5.98
59.20*
± 4.41
81.13*,a
± 10.47
Mango juice
3.33
± 0.62
26.80*
± 3.84
44.93*
± 5.68
66.53*
± 12.96
75.47*
± 14.09
83.53*
± 14.76
91.33*,a
± 16.28
Pineapple juice
3.20
± 0.86
9.67*
± 1.29
21.20*
± 2.62
25.81*
± 3.03
30.80*
± 6.79
28.87*
± 6.51
41.8*,b
± 7.66
Deionized water
0.02
± 0.01
0.02
± 0.01
0.03
± 0.01
0.02
± 0.01
0.02
± 0.01
0.03
± 0.01
0.02c
± 0.01
Citrate buffer
0.02
± 0.01
0.05
± 0.03
0.16*
± 0.04
0.21*
± 0.04
0.24*
± 0.09
0.28*
± 0.06
0.40*,a
± 0.09
Mango juice
0.03
± 0.01
0.11*
± 0.02
0.35*
± 0.08
0.44*
± 0.14
0.39*
± 0.13
0.46*
± 0.13
0.37*,a
± 0.13
Pineapple juice
0.02
± 0.01
0.14*
± 0.01
0.12*
± 0.02
0.13*
± 0.04
0.15*
± 0.03
0.17*
± 0.05
0.22*,b
± 0.04
Rmax (µm)
Rz (µm)
Sm (mm)
*Indicates a significant difference compared to 1 hour for each group and parameter (in rows) according to Tukey’s HSD test ( p < 0.05).
a, b, c, d
Indicate significant differences among four storage media for each parameter (in columns) according to Tukey’s HSD test ( p < 0.05).
a polytetrafluoroethylene cylindrical
mold, 12 mm in diameter and 2.5
mm thick. Each mold was covered
with a glass cover slip to obtain a
flat surface of the specimen. The
specimens were allowed to mature
in their molds in an incubator at
e52
March/April 2011
37°C for one hour after mixing. No
mechanical preparation or abrasions
of specimens were performed.
Four storage media were used
in this study: deionized water (as
a control); citrate buffer solution
(as a benchmark); green mango
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juice (Magnifera indica L.); and
pineapple juice (Ananas comosus
L.). These juices were prepared
from fresh pineapples and mangoes
using a juicer machine and then
sieved with double layers of filter
cloth. The pH of each storage agent
(except deionized water) was determined using a pH meter (Orion
900A, Thermo Fisher Scientific).
Ten pH readings of each storage
agent, except deionized water,
were performed to provide a mean
value and standard deviation (SD)
of the solution.
The 52 discs of each restorative
material were divided into four
subgroups (n = 13). After one hour
in the incubator, the specimens of
each material, still in their molds,
were transferred into the storage
media. Each specimen was stored
in an individual plastic storage pot
containing 25 mL of the storage
medium, which was filled to a sufficient volume to completely cover
both the specimen and the mold.
The immersed specimens were
retained in their molds at 37°C for
the appropriate test period.
A period of immersion was
performed to examine the extensive
effect of each media. During the
test period, the plastic storage pots
containing the specimens were kept
in an incubator at 37°C before
surface roughness was measured. To
maintain a constant pH for the storage solutions, each storage agent was
changed daily.
Each subgroup was subjected
to surface roughness measurement for baseline data (prior to
immersion). Surface roughness
determinations (4.0 mm in evaluated length) were measured by a
profilometer (Surfcorder model
SE-2300, Kosaka Laboratory Ltd.)
with force 4 mN, speed of stylus
0.5 mm/s, and a cutoff of 0.8 mm.
The surface roughness parameters
used (Ra, Rz, Rmax, and Sm [see
Table 2]) were examined.31 Five
evaluations per specimen (1.5 mm
apart) were taken, both before and
after immersion in storage agents
for 168 hours. Testing for surface
roughness was carried out first one
hour after mixing (prior to immersion) and then at 6, 24, 48, 72, 96,
and 168 hours. Changes in surface
roughness were recorded at each
time interval.
To determine the effect of each
storage agent on surface characteristic changes, three specimens
from each of the four storage
agents for each restorative material
tested were examined using scanning electron microscopy (SEM).
Specimens were rinsed with
distilled water for five minutes,
dried, and fixed to an aluminium
cylinder (13 mm in diameter and
10 mm in height). Consequently,
the specimens were sputter-coated
with a gold-palladium alloy (SPI
module sputter, SPI Supplies)
and examined using a scanning
electron microscope (JSM model
5800LV, JEOL USA, Inc.).
Statistical analysis
The data were statistically analyzed
with the Statistical Package for the
Social Sciences (SPSS), version 11.5
(SPSS Inc.). A two-way repeated
ANOVA was performed for each
of the four roughness parameters
to assess the influence of different
storage agents and restorative materials on surface roughness. Tukey’s
HSD multiple comparison test was
used in each of the parameters for
comparing differences for each time
interval as well as for the storage
agents (α = 0.05).
Results
The mean pH and SD of all storage
media (except deionized water)
were as follows: green mango juice,
2.56 ± 0.08; pineapple juice, 3.68
± 0.08; and citrate buffer solution,
5.00 ± 0.02. Both freshly prepared
juices used in this study showed
highly acidic solutions.
The results of the two-way
ANOVA with repeated measure-
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ment revealed statistically significant
differences among the four types of
materials and storage media, as well
as interactions between the type of
material and type of storage media
(p < 0.001 for all comparisons).
Means (± SD) of surface roughness
parameters of the restorative materials immersed in storage media (see
Tables 3–6) indicated increasing
roughness for all materials tested
after immersion for longer times in
all three acidic solutions compared
to the control (deionized water).
For Ketac-S (see Table 3), four
surface roughness parameters had
statistically significant changes. Ra
had significant changes at 6 hours in
citrate buffer solution (p = 0.03) and
mango juice (p = 0.001) and also
at 24 hours in pineapple juice (p =
0.02). Rmax and Rz indicated changes
at 6 hours in all acidic agents (p <
0.001 for all comparisons). Sm demonstrated changes at 6 hours when
exposed to mango juice (p = 0.02)
and pineapple juice (p = 0.03), and
at 24 hours for citrate buffer solution (p < 0.001).
For Fuji II LC (see Table 4),
Ra, Rmax, and Sm had statistically
significant changes after immersion
in all acidic agents for 96 hours (p <
0.001 for all comparisons). Rz was
found to have significant changes
after immersion in mango juice at
48 hours (p = 0.03) and in citrate
buffer solution (p = 0.02) and pineapple juice (p = 0.03) at 96 hours.
For Filtek Z250 (see Table 5), Ra,
Rmax, and Sm established significant
surface changes when exposed to
all acidic agents for 168 hours (p <
0.001 for all comparisons). Rz verified the surface changes statistically
when immersed in mango juice and
citrate buffer solution for 96 hours
and in pineapple juice for 168 hours
(p < 0.001 for all comparisons).
R a, R max, and R z for ValiantPhD (see Table 6) increased
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Dental Materials Gradual surface degradation of restorative materials by acidic agents
Table 4. Means and standard deviations of roughness parameters (R a , R max , R z, and S m) of Fuji II LC immersed in
various storage media for different intervals.
Time (hours)
Roughness
parameters
Storage media
1
6
24
48
72
96
168
Ra (µm)
Deionized water
0.63
± 0.02
0.62
± 0.03
0.60
± 0.05
0.61
± 0.01
0.62
± 0.02
0.60
± 0.02
0.61c
± 0.01
Citrate buffer
0.64
± 0.02
0.69
± 0.04
0.72
± 0.04
0.78
± 0.07
0.77
± 0.04
1.03*
± 0.03
1.12*,b
± 0.14
Mango juice
0.65
± 0.05
0.71
± 0.10
0.69
± 0.12
0.72
± 0.15
0.87
± 0.26
1.13*
± 0.06
1.40*,a
± 0.51
Pineapple juice
0.65
± 0.03
0.67
± 0.04
0.66
± 0.05
0.67
± 0.12
0.67
± 0.09
1.02*
± 0.08
1.07*,b
± 0.35
Deionized water
8.53
± 1.48
8.56
± 1.15
8.60
± 1.01
8.58
± 1.02
8.62
± 1.28
8.61
± 1.19
8.59c
± 1.14
Citrate buffer
8.53
± 1.41
8.63
± 1.32
8.65
± 1.22
8.69
± 1.19
8.73
± 1.04
10.07*
± 0.37
11.13*,b
± 1.34
Mango juice
8.60
± 1.89
9.20
± 1.62
10.6
± 1.34
11.27
± 1.65
13.87
± 1.84
18.27*
± 1.08
23.53*,a
± 2.56
Pineapple juice
8.57
± 1.72
8.60
± 1.09
8.67
± 1.11
8.73
± 1.03
8.80
± 1.01
10.15*
± 1.01
11.02*,b
± 1.84
Deionized water
6.73
± 1.35
6.60
± 1.94
6.53
± 1.22
6.46
± 1.19
6.53
± 1.83
6.60
± 1.21
6.67c
± 1.11
Citrate buffer
6.80
± 1.45
6.81
± 1.23
6.87
± 1.31
6.97
± 1.41
8.13
± 0.16
9.02*
± 0.18
9.51*,b
± 1.10
Mango juice
6.73
± 1.08
6.80
± 1.81
6.84
± 0.25
7.62*
± 0.69
7.87*
± 1.42
10.53*
± 1.74
12.33*,a
± 1.69
Pineapple juice
6.78
± 1.41
6.79
± 1.26
6.73
± 1.36
6.73
± 1.25
6.97
± 0.14
7.96*
± 0.30
8.95*,b
± 0.35
Deionized water
0.25
± 0.11
0.26
± 0.05
0.24
± 0.06
0.25
± 0.05
0.28
± 0.06
0.27
± 0.04
0.26c
± 0.07
Citrate buffer
0.26
± 0.04
0.25
± 0.09
0.27
± 0.13
0.26
± 0.09
0.28
± 0.02
0.32*
± 0.05
0.35*,b
± 0.02
Mango juice
0.27
± 0.04
0.24
± 0.19
0.28
± 0.08
0.29
± 0.05
0.28
± 0.07
0.37*
± 0.08
0.39*,a
± 0.09
Pineapple juice
0.28
± 0.05
0.28
± 0.05
0.29
± 0.04
0.21
± 0.08
0.22
± 0.07
0.32*
± 0.04
0.36*,b
± 0.05
Rmax (µm)
Rz (µm)
Sm (mm)
*Indicates significant difference compared to 1 hour for each group and parameter (in rows) according to Tukey’s HSD test ( p < 0.05)
a, b, c
Indicate significant differences among four storage media for each parameter (in columns) according to Tukey’s HSD test ( p < 0.05)
slightly but did not illustrate any
statistically significant changes
(p > 0.05). However, Sm did have
statistically significant changes
when immersed for 168 hours in
all acidic agents (p < 0.001 for all
comparisons).
e54
March/April 2011
Tukey’s HSD multiple comparison
tests among the four storage agents
for each material tested revealed that,
for all parameters, the most statistically significant changes were found
after being immersed in mango juice,
followed by citrate buffer solution
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(p < 0.001 for all comparisons). The
least significant value was found
after immersion in deionized water
(p < 0.001 for all comparisons).
After evaluating the four types
of restorative materials for all four
parameters, the changes in surface
Table 5. Means and standard deviations of roughness parameters (R a , R max , R z, and S m) of Filtek Z250 immersed in
various storage media for different intervals.
Time (hours)
Roughness
parameters
Storage media
1
6
24
48
72
96
168
Ra (µm)
Deionized water
0.02
± 0.01
0.02
± 0.01
0.03
± 0.01
0.02
± 0.01
0.02
± 0.01
0.03
± 0.01
0.02c
± 0.01
Citrate buffer
0.03
± 0.01
0.04
± 0.02
0.03
± 0.01
0.05
± 0.02
0.04
± 0.02
0.04
± 0.01
0.06*,a
± 0.01
Mango juice
0.02
± 0.01
0.03
± 0.01
0.03
± 0.02
0.02
± 0.01
0.03
± 0.02
0.02
± 0.01
0.07*,a
± 0.01
Pineapple juice
0.02
± 0.01
0.03
± 0.01
0.02
± 0.01
0.03
± 0.01
0.03
± 0.02
0.02
± 0.01
0.04*,b
± 0.01
Deionized water
0.53
± 0.02
0.55
± 0.11
0.56
± 0.05
0.56
± 0.04
0.57
± 0.06
0.58
± 0.05
0.60c
± 0.11
Citrate buffer
0.48
± 0.11
0.60
± 0.13
0.65
± 0.06
0.68
± 0.11
0.72
± 0.12
0.78
± 0.10
0.93*,b
± 0.09
Mango juice
0.51
± 0.11
0.53
± 0.03
0.58
± 0.11
0.59
± 0.09
0.63
± 0.11
0.72
± 0.12
1.17*,a
± 0.16
Pineapple juice
0.46
± 0.11
0.47
± 0.05
0.53
± 0.06
0.58
± 0.03
0.62
± 0.12
0.68
± 0.08
0.92*,b
± 0.08
Deionized water
0.29
± 0.09
0.31
± 0.11
0.30
± 0.09
0.32
± 0.11
0.34
± 0.08
0.32
± 0.11
0.31d
± 0.07
Citrate buffer
0.31
± 0.09
0.34
± 0.05
0.36
± 0.13
0.42
± 0.12
0.46
± 0.09
0.65*
± 0.08
0.73*,b
± 0.09
Mango juice
0.29
± 0.12
0.31
± 0.06
0.43
± 0.14
0.52
± 0.09
0.55
± 0.11
0.87*
± 0.10
1.07*,a
± 0.26
Pineapple juice
0.28
± 0.11
0.28
± 0.09
0.32
± 0.11
0.35
± 0.08
0.37
± 0.11
0.39
± 0.12
0.58*,c
± 0.05
Deionized water
0.02
± 0.01
0.03
± 0.02
0.02
± 0.01
0.02
± 0.01
0.03
± 0.01
0.02
± 0.01
0.02c
± 0.01
Citrate buffer
0.03
± 0.01
0.03
± 0.02
0.02
± 0.01
0.03
± 0.01
0.03
± 0.02
0.03
± 0.01
0.06*,b
± 0.01
Mango juice
0.02
± 0.01
0.02
± 0.01
0.03
± 0.01
0.02
± 0.01
0.03
± 0.02
0.03
± 0.01
0.07*,a
± 0.02
Pineapple juice
0.02
± 0.01
0.03
± 0.01
0.02
± 0.01
0.02
± 0.01
0.03
± 0.02
0.03
± 0.01
0.05*,b
± 0.01
Rmax (µm)
R z (µm)
S m (mm)
*Indicates significant difference compared to 1 hour for each group and parameter (in rows) according to Tukey’s HSD test ( p < 0.05).
a, b, c, d
Indicate significant differences among four storage media for each parameter (in columns) according to Tukey’s HSD test ( p < 0.05).
roughness could be ranked as
Ketac-S > Fuji II LC > Filtek Z250
> Valiant-PhD. The ranking order
of the erosive potential effect of the
storage media was as follows: mango
juice > citrate buffer solution >
pineapple juice > deionized water.
The SEM photomicrographs (Fig.
1–4) illustrated the gradual surface
degradation of the various restorative
materials tested. Before immersion,
Ketac-S and Valiant-PhD specimens
demonstrated rough surfaces and
the protrusion of filler particles (Fig.
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1A and 4A, respectively). Fuji II
LC specimens demonstrated a few
rough surfaces (Fig. 2A), while Filtek
Z250 specimens demonstrated the
smoothest surfaces (Fig. 3A).
After immersion in various storage
media for 72 and 168 hours, Fuji II
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Dental Materials Gradual surface degradation of restorative materials by acidic agents
Table 6. Means and standard deviations of roughness parameters (R a , R max , R z, and S m) of Valiant-PhD immersed in
various storage media for different intervals.
Roughness
parameters
Ra (µm)
R max (µm)
R z (µm)
S m (mm)
Time (hours)
Storage media
1
6
24
48
72
96
168
Deionized water
1.24
± 0.15
1.23
± 0.12
1.25
± 0.19
1.26
± 0.15
1.24
± 0.09
1.25
± 0.11
1.26
± 0.12
Citrate buffer
1.26
± 0.16
1.25
± 0.11
1.27
± 0.35
1.27
± 0.16
1.28
± 0.26
1.28
± 0.16
1.29
± 0.22
Mango juice
1.27
± 0.16
1.28
± 0.19
1.29
± 0.21
1.30
± 0.12
1.31
± 0.19
1.31
± 0.16
1.33
± 0.11
Pineapple juice
1.27
± 0.14
1.27
± 0.26
1.28
± 0.15
1.28
± 0.26
1.27
± 0.13
1.28
± 0.00
1.29
± 0.26
Deionized water
12.27
± 1.43
12.27
± 2.55
12.30
± 3.54
12.29
± 2.61
12.28
± 2.63
12.29
± 2.57
12.30
± 3.10
Citrate buffer
12.26
± 1.60
12.27
± 1.76
12.28
± 1.71
12.28
± 1.79
12.29
± 1.89
12.30
± 1.49
12.32
± 1.13
Mango juice
12.27
± 1.22
12.40
± 1.04
12.51
± 1.14
12.58
± 1.33
13.31
± 2.97
13.42
± 2.02
13.17
± 2.11
Pineapple juice
12.28
± 1.43
12.30
± 1.58
12.31
± 1.48
12.31
± 1.66
12.33
± 1.61
12.33
± 1.73
12.34
± 1.57
Deionized water
8.95
± 1.46
8.99
± 2.65
8.98
± 1.72
8.98
± 1.49
8.99
± 1.42
9.01
± 1.52
8.99
± 1.49
Citrate buffer
8.97
± 1.05
9.03
± 1.12
9.10
± 1.38
9.09
± 1.24
9.11
± 1.09
9.12
± 1.14
9.15
± 1.13
Mango juice
8.93
± 1.43
9.03
± 1.37
9.06
± 1.45
9.08
± 1.43
9.11
± 1.74
9.30
± 1.79
9.45
± 1.25
Pineapple juice
9.00
± 1.51
9.02
± 1.81
9.05
± 1.81
9.07
± 1.15
9.08
± 1.08
9.12
± 1.16
9.13
± 1.31
Deionized water
0.10
± 0.02
0.11
± 0.02
0.11
± 0.03
0.11
± 0.02
0.12
± 0.02
0.10
± 0.00
0.11b
± 0.02
Citrate buffer
0.12
± 0.03
0.11
± 0.02
0.12
± 0.02
0.11
± 0.02
0.10
± 0.01
0.12
± 0.03
0.17*,a
± 0.02
Mango juice
0.11
± 0.02
0.11
± 0.03
0.11
± 0.02
0.10
± 0.01
0.12
± 0.01
0.11
± 0.02
0.18*,a
± 0.02
Pineapple juice
0.11
± 0.02
0.13
± 0.04
0.12
± 0.02
0.13
± 0.05
0.12
± 0.04
0.13
± 0.05
0.16*,a
± 0.02
*Indicates significant difference compared to 1 hour for each group and parameter (in rows) according to Tukey’s HSD test ( p < 0.05).
a, b
Indicate significant differences among four storage media for each parameter (in columns) according to Tukey’s HSD test ( p < 0.05).
LC specimens displayed more rough
surface pits that increased with time
in citrate buffer solution (Fig. 2D
and 2E, respectively) and mango
juice (Fig. 2F and 2G, respectively).
Roughening patterns also increased
with time for Ketac-S (Fig. 1D–1G)
e56
March/April 2011
and Valiant-PhD (Fig. 4D–4G),
after citrate buffer solution and
mango juice immersion for 72 and
168 hours. Filler particles were
more clearly seen at 168 hours than
at 72 hours. For Filtek Z250 (Fig.
3), even after 72 and 168 hours
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www.agd.org
in all storage media, the specimen surfaces still showed mostly
smooth surfaces. After the materials were immersed in pineapple
juice (Fig. 1I, 2I, 3I, and 4I), the
specimen surfaces seemed to have a
“plaque-like” covering.
A
B
C
D
E
F
G
H
I
Figure 1. SEM photomicrographs of Ketac-S before and after immersion in various storage media (5,000x magnification). A: Before immersion. B: After
immersion in deionized water for 72 hours. C: After immersion in deionized water for 168 hours. D: After immersion in citrate buffer solution for 72 hours.
E: After immersion in citrate buffer solution for 168 hours. F: After immersion in mango juice for 72 hours. G: After immersion in mango juice for 168
hours. H: After immersion in pineapple juice for 72 hours. I: After immersion in pineapple juice for 168 hours.
Discussion
The results of this study support
rejection of the null hypothesis
because the acidic agents used could
lead to significantly changed surface
roughness of the materials evaluated. This study concentrated solely
on erosion by static immersion of
restorative materials in solutions
over a period of 168 hours. The
effect of attrition from chewing
habits was not measured.
The oral cavity is a complex
environment, and it is difficult to
simulate clinically. For this reason,
a long immersion time was used
to simulate the extensive effect of
acidic solutions.
Currently, there are two methods
used to measure surface roughness
in dentistry: contact methods and
noncontact methods.32 Noncontact
methods use a light beam or a laser
beam to receive a surface profile.
One of the disadvantages of this
method is that shiny surfaces,
which can be found in composite
resin and glass ionomer cement
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surfaces, are sometimes difficult
to measure because of the scattering effect of reflected light. This
can result in false values being
recorded.32 For this reason, the
current study used a profilometer, which is a contact method.
Although it has been claimed
that the stylus tip used in contact
methods can damage or alter the
surfaces, no scratches were observed
in SEM analysis because the stylus
tip traced on specimen surfaces
with very little force (4 mN).31
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Dental Materials Gradual surface degradation of restorative materials by acidic agents
A
B
C
D
E
F
G
H
I
Figure 2. SEM photomicrographs of Fuji II LC before and after immersion in various storage media (5,000x magnification). A: Before immersion. B: After
immersion in deionized water for 72 hours. C: After immersion in deionized water for 168 hours. D: After immersion in citrate buffer solution for 72 hours.
E: After immersion in citrate buffer solution for 168 hours. F: After immersion in mango juice for 72 hours. G: After immersion in mango juice for 168
hours. H: After immersion in pineapple juice for 72 hours. I: After immersion in pineapple juice for 168 hours.
The most common roughness
parameter used in both dentistry
and engineering is the R a value.33
However, the R a value is limited in
that it is two-dimensional and it
only allows information about the
average roughness height. It also
provides no information regarding
the surface profile.31 To resolve
this limitation, the current study
used three additional roughness
parameters—R z, R max, and Sm—to
provide a qualitative result in three
dimensions. The combination of
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March/April 2011
quantitative measurements and
qualitative data by SEM supports
an obvious characterization of the
surfaces tested.32-34 In addition,
roughness measurements obtained
from relatively short scans might
not be representative of the entire
surface, so many measuring scans
would be necessary when using
a profilometer, as in the current
study. The roughness values of the
materials tested were in agreement
with the other findings.35-38
The current study revealed that the
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acidic agents tested created rough
surfaces on the restorative materials.
Previous studies have reported that
increasing the surface roughness of
restorative materials could promote
plaque accumulation.15-17 The critical
mean Ra for the adhesion and colonization of bacteria on restorative
materials has been reported to be
0.2 μm, which matches the results
of the present study.39 These results
may lead to bacterial colonization,
which would result in clinical failure
of restorations; however, the current
A
B
C
D
E
F
G
H
I
Figure 3. SEM photomicrographs of Filtek Z250 before and after immersion in various storage media (5,000x magnification). A: Before immersion. B: After
immersion in deionized water for 72 hours. C: After immersion in deionized water for 168 hours. D: After immersion in citrate buffer solution for 72 hours.
E: After immersion in citrate buffer solution for 168 hours. F: After immersion in mango juice for 72 hours. G: After immersion in mango juice for 168
hours. H: After immersion in pineapple juice for 72 hours. I: After immersion in pineapple juice for 168 hours.
study did not examine this particular
relationship, so further studies are
required to examine this correlation.
The four restorative materials
selected for this study are those
most commonly used for restoring
eroded teeth.3 The results proved
that immersing these restorative
materials into acidic agents could
cause surface roughness at different
intervals. Ketac-S and Fuji II LC,
which are modified from conventional glass ionomer cement, displayed changes in surface roughness
over a shorter time period compared
to amalgam and composite resin.
The results indicated that Ketac-S,
a metal-reinforced glass ionomer
cement, degraded more than Fuji II
LC, a resin-modified glass ionomer
cement. One reason for this could
be the effect of acid on interfacial
bonding between the silver alloy
fillers and the polyacrylate matrix
of Ketac-S, causing the dissolution of the metal ion.14 Another
reason could be the chelating effect
of the acid in acidic agents. This
www.agd.org
phenomenon takes place by complex binding of chelating acids to
dissolved metal ions from Ketac-S
and results in more ion dissolution
and degradation of Ketac-S to
maintain electrical neutrality. These
results could illustrate that acidic
agents could degrade Ketac-S more
than the other materials tested.
In fact, there are many types of
acids and other components that
can have the chemical erosive effect
of sour fruits on dental materials.
Citric, malic, ascorbic, and fumalic
General Dentistry
March/April 2011
e59
Dental Materials Gradual surface degradation of restorative materials by acidic agents
A
B
C
D
E
F
G
H
I
Figure 4. SEM photomicrographs of Valiant-PhD before and after immersion in various storage media (5,000x magnification). A: Before immersion.
B: After immersion in deionized water for 72 hours. C: After immersion in deionized water for 168 hours. D: After immersion in citrate buffer solution for
72 hours. E: After immersion in citrate buffer solution for 168 hours. F: After immersion in mango juice for 72 hours. G: After immersion in mango juice for
168 hours. H: After immersion in pineapple juice for 72 hours. I: After immersion in pineapple juice for 168 hours.
acids are the major organic acids
in mangoes, while citric acid and
malic acid also are the major acids
in pineapples.25 A previous study
reported that citric acid (pH = 2.5)
is the most aggressive storage
medium for glass ionomer cement
and compomer, as compared with
phosphoric acid (pH = 2.1) and
lactic acid (pH = 2.7).23 In the current study, green mango juices at a
pH of 2.56 were harmful to restorative materials, especially Ketac-S.
It also was noted that pineapple
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March/April 2011
juice (pH = 3.68) also degraded the
restorative materials. However, pineapple juice showed a lower chemical
erosive effect on surface roughness
compared to the citrate buffer solution (pH = 5.00). It is possible that
other components in pineapple juice
provide protection against erosion.
This is consistent with the SEM
photomicrographs, which displayed
a “plaque-like” layer covering the
specimens that had been immersed
in pineapple juice. Further investigation of this finding is required.
General Dentistry
www.agd.org
The most significant discovery of
this in vitro study was that amalgam
and composite resin could endure
acidic solutions more successfully
than metal-reinforced glass ionomer
cement and resin-modified glass
ionomer cement. Therefore, when
restoring teeth from the effects of
erosion, amalgam or composite resin
could be the most suitable materials.
However, it must be noted that
the current study had some limitations. Elements of saliva, such as
flow rate and buffering capacity,
could alter the results. Also, while
the current study attempted to
duplicate the oral environment,
the presence of water, temperature
changes, and a varying pH level in
the oral cavity could considerably
affect the properties of restorations.
In addition, the present study
evaluated only the in vitro effect.
Further studies are required to
elaborate the effect of acidic agents
or sour fruit juice on restorative
materials in vivo.
Conclusion
Within the limitations of this study,
it can be concluded that acidic
agents (citrate buffer solution, green
mango juice, and pineapple juice)
affect surface roughness changes of
dental restorative materials. Amalgam (Valiant-PhD) and composite
resin (Filtek Z250) were less affected
by acid damage than both types of
glass ionomer cement (Ketac-S and
Fuji II LC).
Acknowledgements
The authors would like to thank
Professor Peter A. Leggat, James
Cook University, Townsville, Australia, for his suggestions in the data
analysis and for proofing the manuscript. This study was supported
by a grant from Prince of Songkla
University.
Author information
Dr. Hengtrakool is an assistant
professor and Dr. Kukiattrakoon is
an associate professor, Department
of Conservative Dentistry, Faculty
of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand,
where Dr. Kedjarune-Leggat is an
associate professor, Department of
Oral Biology and Occlusion.
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3. Lambrechts P, Van Meerbeek B, Perdigao J,
Gladys S, Braem M, Vanherle G. Restorative
therapy for erosive lesions. Eur J Oral Sci 1996;
104(2 (Pt 2)):229-240.
4. Powers JM, Sakaguchi RL. Craig’s restorative
dental materials, ed. 12. St. Louis, Missouri: Elsevier Mosby;2006:192-194.
5. Saito S, Tosaki S, Hirota K. Characteristics of
glass-ionomer cements. In: Davidson CL, Mjor
IA, eds. Advances in glass-ionomer cements.
Chicago: Quintessence;1999:16-23.
6. McLean JW, Wilson AD. Glass ionomer cements.
Br Dent J 2004;196(9):514-515.
7. McLean JW, Gasser O. Glass-cermet cements.
Quintessence Int 1985;16(5):333-343.
8. Walls AW, Adamson J, McCabe JF, Murray JJ. The
properties of a glass polyalkenoate (ionomer)
cement incorporating sintered metallic particles.
Dent Mater 1987;3(3):113-116.
9. Williams JA, Billington RW, Pearson GJ. The
comparative strengths of commercial glass-ionomer cements with and without metal additions. Br Dent J 1992;172(7):279-282.
10. Wilson AD. Resin-modified glass-ionomer cements. Int J Prosthodont 1990;3(5):425-429.
11. Shabanian M, Richards LC. In vitro wear rates of
materials under different loads and varying pH.
J Prosthet Dent 2002;87(6):650-656.
12. McKenzie MA, Linden RW, Nicholson JW. The
physical properties of conventional and resinmodified glass-ionomer dental cements stored in
saliva, proprietary acidic beverages, saline and
water. Biomaterials 2003;24(22):4063-4069.
13. Ferracane JL. Materials in dentistry: Principles
and applications. Philadelphia, Pennsylvania:
Lippincott Williams and Willkins;2001:102-109.
14. Sazak-Ovecoglu H, Gunday M, Ovecoglu ML,
Tarcin B. Chemical degradation of restorative materials. Key Eng Mater 2004;264-268:2009-2012.
15. Dunkin RT, Chambers DW. Gingival response to
Class V composite resin restorations. J Am Dent
Assoc 1983;106(4):482-484.
16. Shintani H, Satou J, Satou N, Hayashihara H,
Inoue T. Effects of various finishing methods on
staining and accumulation of Streptococcus mutans HS-6 on composite resins. Dent Mater
1985;1(6):225-227.
17. Quirynen M, Bollen CM. The influence of surface
roughness and surface-free energy on supraand subgingival plaque formation in man. A
review of the literature. J Clin Periodontol 1995;
22(1):1-14.
18. Bassiouny MA, Kuroda S, Yang J. Topographic
and radiographic profile assessment of dental
erosion. Part I: Effect of acidulated carbonated
beverages on human dentition. Gen Dent 2007;
55(4):297-305.
19. Bassiouny MA, Yang J, Kuroda S. Topographic and
radiographic profile assessment of dental erosion.
Part II: Effect of citrus fruit juices on human dentition. Gen Dent 2008;56(2):136-143.
20. Mante MO, Saleh N, Tanna NK, Mante FK. Softening patterns of light cured glass ionomer cements. Dent Mater 1999;15(5):303-309.
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21. Wongkhantee S, Patanapiradej V, Maneenut C,
Tantbirojn D. Effect of acidic food and drinks on
surface hardness of enamel, dentine, and toothcoloured filling materials. J Dent 2006;34(3):
214-220.
22. von Fraunhofer JA, Rogers MM. Effects of sports
drinks and other beverages on dental enamel.
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23. Nicholson JW, Gjorgievska E, Bajraktarova B,
McKenzie MA. Changes in properties of polyacidmodified composite resins (compomers) following storage in acidic solutions. J Oral Rehabil
2003;30(6):601-607.
24. West NX, Hughes JA, Addy M. The effect of pH on
the erosion of dentine and enamel by dietary acids in vitro. J Oral Rehabil 2001;28(9):860-864.
25. Bartolome AP, Ruperez P, Fuster C. Pineapple
fruit: Morphological characteristics, chemical
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1995;53(1):75-79.
26. Hughes JA, Jandt KD, Baker N, Parker D, Newcombe RG, Eisenburger M, Addy M. Further
modification to soft drinks to minimize erosion.
A study in situ. Caries Res 2002;36(1):70-74.
27. Kunzel W, Cruz MS, Fischer T. Dental erosion in
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104-109.
28. Bell EJ, Kaidonis J, Townsend G, Richards L.
Comparison of exposed dentinal surfaces resulting from abrasion and erosion. Aust Dent J
1998;43(5):362-366.
29. Kieser JA, Dennison KJ, Kaidonis JA, Huang D,
Herbison PG, Tayles NG. Patterns of dental wear
in the early Maori dentition. Int J Osteoarchaeol
2001;11(3):206-217.
30. Chuajedong P, Kedjarune-Leggat U, Kertpon D,
Chongsuvivatwong V, Benjakul P. Associated
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Oral Rehabil 2002;29(10):997-1002.
31. Stout KJ. Surface roughness: Measurement, interpretation and significance of data. Mater Eng
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NHF. Comparison of methods for measuring surface roughness of ceramic. J Oral Rehabil
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33. Sunnegardh-Gronberg K, van Dijken JW. Surface
roughness of a novel “ceramic restorative cement” after treatment with different polishing
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NHF. Comparison of two stylus methods for
measuring surface texture. Dent Mater 1999;
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35. Turssi CP, Hara AT, Serra MC, Rodrigues AL Jr.
Effect of storage media upon the surface micromorphology of resin-based restorative materials.
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37. Yip HK, To WM, Smales RJ. Effects of artificial
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newer glass ionomer cements. Oper Dent 2004;
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Manufacturers
Dentsply Caulk, Milford, DE
800.532.2855, www.caulk.com
Dentsply International, York, PA
800.877.0020, www.dentsply.com
GC America Inc., Alsip, IL
800/323-7063, www.gcamerica.com
JEOL USA, Inc., Peabody, MA
978.535.5900, www.jeol.com
Kosaka Laboratory Ltd., Tokyo, Japan
81.3.5812.2011, www.kosakalab.co.jp
SPI Supplies, West Chester, PA
800.242.4774, www.2spi.com
SPSS Inc., Chicago, IL
800.543.2185, www.spss.com
Thermo Fisher Scientific, Waltham, MA
781.622.1000, www.thermofisher.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
COMMENT
e62
March/April 2011
General Dentistry
www.agd.org
Complete Dentures
Cast metal bases as an economical alternative
for the severely resorbed mandible
Luis Rueda, DDS, MSD
n
Fong Wong, DDS, MSD
n
Marissa Cooper, DMD
Resorption of the alveolar ridge is a common problem in
edentulous patients and can compromise the stability and function
of dentures. Resorption and its consequences can be minimized
when strategically placed implants are used; however, this option
is financially out of reach for many patients.
The article discusses a more cost-effective alternative (metalbased dentures) for patients with ridge resorption. In certain
M
any patients who lose
their natural teeth adapt
to complete dentures as a
result of the accommodation factors
inherent to the oral cavity. However,
problems can arise when patients
have been edentulous for many years
and the residual alveolar ridges have
undergone extensive resorption.1
The severely resorbed mandible
is associated with most problems
encountered by edentulous
patients.2 The lack of retention and
stability of the mandibular denture
makes the normal functions of mastication and phonation extremely
difficult for many of these patients.
The introduction of dental
implants has created new treatment
options for patients who have
advanced resorption. Implantsupported overdentures have become
the standard of care for cases of mandibular edentulism.3 However, for
many patients, the greatest obstacle
to implant therapy is the high cost.
In a dental school environment,
where most of the patient population faces financial limitations,
implants may not be a viable option.
Metal bases have been used in
dentistry for many years; however,
despite certain advantages, they
n
Andrew Clark, DMD
environments, like a dental school, where patients are looking for
solutions to their dental problems at a reasonable price, cast metal
bases can be a feasible economical alternative for edentulous
patients. Both cases presented here demonstrated a significant
improvement in stability, phonation, and mastication.
Received: March 19, 2010
Accepted: June 7, 2010
are not widely used in clinical
practice. Advantages of metal-based
dentures include increased retention; less occlusal discrepancy; fewer
sore spots; a reduced incidence
of fracture; more comfort for the
patient; better thermal conduction;
increased stability; a thinner palate,
which facilitates speech; improved
preservation of the residual alveolar
ridge; decreased porosity; decreased
deformation during lateral mandibular function; and more accurate
tissue detail.1,2,4,5 Regli and Kydd
found that a metal denture base
was eight times more resistant to
deformation than dentures with an
acrylic resin base.6
In a subsequent study, Regli and
Gaskill concluded that the ability of
the denture base to resist deformation is an important factor in the
adequate distribution of stress to the
supporting tissue.7 Their study indicated that during mastication, acrylic
resin denture bases exhibited greater
deformation compared with metal
denture bases or denture bases with
metal inserts. Added strength and
increase accuracy of fit complement
the reduction in base deformation
and may help to prevent excessive
loss of the supporting structures.2,8
www.agd.org
Of course, there also are disadvantages to metal bases, including
increased cost, especially if the clinician uses noble metal alloys or more
technique-sensitive metals, such as
titanium.5-7,9 Allergies to nonprecious alloys have been reported,
with a frequency of 10% in women
and 1% in men.4
Many authors have identified
relining and rebasing procedures as
a problem when using metal bases.
However, several articles describe
sandblasting the metal base and
applying a metal primer to condition and bond the relining acrylic
material.10-13
A number of dental alloys have
been used to fabricate metal bases.
Gold use was described in classic
articles by Grunewald and Lang.1,5
Aluminum has been used for maxillary metal bases due to its light
weight.14-16 Recently, titanium has
been used due to its positive physical properties of excellent corrosion
resistance, light weight, and biocompatibility.8 However, titanium
is difficult to cast due to its high
melting point, and milled frameworks can be expensive to fabricate.
The current price of gold is so high
that it cannot be considered when
General Dentistry
March/April 2011
e63
Complete Dentures Cast metal bases as an economical alternative for the severely resorbed mandible
Fig. 1. Severely resorbed mandibular ridge.
Fig. 2. Metal base design on the master cast.
Fig. 4. Metal base framework evaluated in the patient’s mouth.
patients have financial constraints.
Chrome-cobalt alloys have been
used extensively in the fabrication of removable partial denture
frameworks due to their reasonable
cost, and the fabrication technique
is commonly used in most dental
laboratories.8
Case reports
Case report No. 1
A 57-year-old woman in good overall health sought dental treatment at
the predoctoral clinical program at
the University of Florida College of
Dentistry. Her chief complaint was
difficulty using her existing complete
dentures, especially the mandibular
denture, which had no retention,
making it extremely challenging for
e64
March/April 2011
her to chew and speak. The only
way she could tolerate the dentures
was to use dental adhesive.
During the intraoral examination, she was classified as a completely edentulous Type III patient
(Fig. 1), according to the Prosthodontic Diagnostic Index.17 She
reported having the greatest difficulty with her mandibular complete
denture. Her dental history revealed
that all of her maxillary and
mandibular teeth were extracted in
2007 due to advanced periodontal
disease. Immediate dentures were
placed at the time of extraction.
The patient reported that she
continued to be uncomfortable
with her dentures, even after several
adjustment appointments.
General Dentistry
www.agd.org
Fig. 3. Metal base on the master cast.
Based on the patient’s prior dental
experience, an implant-retained
overdenture with two implants was
presented as the ideal treatment
option. However, the high cost of
this option caused the patient to
reject it. A metal-based complete
denture was presented as an alternative treatment option to attempt
to reduce the problems she was
experiencing with a conventional
acrylic-based denture. The treatment
plan was approved and informed
consent was obtained.
Alginate impressions (Jeltrate,
Dentsply Caulk) were taken using
plastic stock trays, (Coe, GC
America Inc.). The preliminary
impressions were poured immediately with a fast-setting dental stone
(Snap Stone, Whip-Mix Corporation) so that preliminary casts could
be fabricated at the first appointment. This was done to evaluate the
cast, to determine areas of tissue
displaced by the stock tray, and to
fabricate an accurate custom tray.
On this preliminary cast, the areas
of attached tissue were determined
by manipulating the lips, cheeks,
and tongue and were delineated
on the cast. This outline was used
to fabricate a custom tray (Triad,
Dentsply Trubyte). The custom tray
was evaluated for overextension in
the mouth, and border molding was
accomplished using green modeling
plastic impression compound (Kerr
Corporation), a Bunsen burner, an
alcohol torch, and a water bath set
at 140°F.
Polysulfide impression material
(Permlastic, Kerr Corporation) was
used to make the maxillary and
mandibular final impressions. These
impressions were boxed using boxing
wax strips (Henry Schein, Inc.) and
poured using Microstone (WhipMix Corporation). After the stone
cast was separated from the impression, the extension of the metal base
borders was defined on the master
cast (Fig. 2). A surveyor (DeringerNey Inc.) was used to determine
areas of undercuts, especially in
the posterior lingual area. The final
impression and the master cast were
sent to a commercial dental laboratory for the fabrication of a chromecobalt metal base (Fig. 3).
The metal base was evaluated on
the master cast and in the patient’s
mouth (Fig. 4). Extension, retention, and stability were evaluated
while the patient performed different movements with her tongue
and cheeks. A wax rim was adapted
on the mandibular metal base to
make a centric relation record using
Blu-Mousse (Parkell) (Fig. 5). A
face-bow record was taken. It was
observed that, with the metal base,
the occlusal record could be made
in a more stable manner.
Teeth were selected using the Blueline shade and mold guides (Ivoclar
Vivadent Inc.). Anterior teeth were
selected according to manufacturer’s
guidelines. Orthoplane zero degree
teeth (Ivoclar Vivadent Inc.) were
selected for the posterior teeth. A
wax try-in was completed, patient
approval was obtained, and the
dentures were sent to the laboratory
for processing (Fig. 6).
When the dentures were delivered
to the patient, pressure-indicating
Fig. 5. Metal base occlusal rim on the master
cast.
paste (Henry Schein, Inc.) was used
to note pressure spots and adjustments were made using a metal
polishing kit. The occlusion was
checked using Surgident articulating paper (Heraeus Dental North
America) (Fig. 7). The patient was
evaluated again after 24 hours and
after one week.
At a six-month recall appointment,
the patient reported a significant
improvement in stability, phonation,
and mastication; she was extremely
satisfied with the final result.
Fig. 6. A wax try-in in the patient’s mouth.
Fig. 7. The intaglio surface of the metal-based
mandibular denture.
Case report No. 2
A 71-year-old woman presented
with multiple medical problems,
which were being treated by her
primary care physician. She was
taking several medications for
hypertension, hypercholesteromia,
diabetes, and antidepressants. No
contraindication for dental treatment was found. The patient had
been treated in the predoctoral
clinic six months earlier, when
she was fitted with a maxillary
and mandibular acrylic-based
denture. The patient returned on
several occasions for adjustments,
reporting that she had multiple
sore spots, that the mandibular
denture was unstable, and that she
was unable to eat while wearing
it. Flanges were reduced to correct
www.agd.org
overextensions and Coe-Soft (GC
America Inc.) was used on several
occasions.
After six months of unsuccessful
results, it was decided to replace the
acrylic-based mandibular denture
with a metal-based mandibular
denture. The denture was fabricated
using the procedures outlined in
case report No. 1. Special attention was given to the design of
the custom tray in order to limit
the extension of the impression to
the attached tissue. At the try-in
appointment, special care was taken
to avoid impingement of the tissue
and overextension.
The patient was evaluated after
24 hours and after one week, and
General Dentistry
March/April 2011
e65
Complete Dentures Cast metal bases as an economical alternative for the severely resorbed mandible
minor adjustments were made to
the occlusion and the base. This
patient also reported a significant
improvement in stability, phonation,
and mastication and was extremely
satisfied with the final result.
Summary
This clinical report describes the
use of metal-based mandibular
complete dentures in two patients
for whom conventional acrylic
dentures were less than ideal. The
lack of retention and stability of
the mandibular denture made it
extremely difficult for these patients
to eat and speak normally.
The mandibular two-implant
overdenture has become the standard of care for edentulous patients,
especially for those with advanced
resorption. However, the high cost
of implant therapy remains an
obstacle, and implants may not be
a viable option for many patients in
a dental school environment. Cast
metal bases could be a more economical option for patients experiencing problems with conventional
acrylic dentures.
Acknowledgments
The authors would like to acknowledge Dr. A. Nimmo for the multiple
corrections made to this article.
Disclaimer
None of the authors have any
affiliation with or interests in any
of the manufacturers mentioned in
this article.
Author information
Dr. Rueda is a clinical assistant professor, Department of Prosthodontics, University of Florida College of
Dentistry in Gainesville, where Dr.
Wong is an assistant professor and
Dr. Clark is serving an orthodontic
residency. Dr. Cooper is serving
an orthodontic residency, College
of Dental Medicine, Nova Southeastern University, Ft. LauderdaleDavie, FL.
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17. McGarry TJ, Nimmo A, Skiba JF, Ahlstrom RH,
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Manufacturers
Dentsply Caulk, Milford, DE
800.532.2855, www.caulk.com
Dentsply Trubyte, York, PA
800.877.0020, trubyte.dentsply.com
Deringer-Ney Inc., Blaine, MN
763.792.9500, www.deringerney.com
GC America Inc., Alsip, IL
800.323.7063, www.gcamerica.com
Henry Schein, Inc., Melville, NY
800.472.4346, www.henryschein.com
Heraeus Dental North America, South Bend, IN
800.431.1785, www.heraeus-dental-us.com
Ivoclar Vivadent Inc., Amherst, NY
800.533.6825, www.ivoclarvivadent.us
Kerr Corporation, Orange, CA
800.537.7123, www.kerrdental.com
Parkell, Farmingdale, NY
800.243.7446, www.parkell.com
Whip-Mix Corporation, Louisville, KY
800.626.5651, www.whipmix.com
COMMENT
e66
March/April 2011
General Dentistry
www.agd.org
endodontics
Effect of fiber posts with different
emerging diameters on the fracture
strength of restored crownless teeth
Paolo Baldissara, DDS
n
Francesca Zicari, DDS
n
LuizFelipeValandro,DDS,MS,PhD
The relatively low elastic modulus of fiber posts reduces the risk
of root fracture, but it also decreases composite core stabilization.
To compensate for the lack of rigidity, larger post sizes can be
necessary when restoring crownless teeth that have significant
internal destruction of the root canal. This study evaluated the
effectiveness of fiber posts with different emerging diameters and
shapes on composite core stabilization as measured by fracture
strength testing.
Fracture strengths ranged from 262.6 ± 81 N to 422.8 ± 56 N.
A one-way ANOVA test showed that fracture strength was affected
I
n clinical practice, endodontically
treated teeth often completely
lose their crowns. In these cases,
a composite core must be rebuilt
completely around the fiber post.1
Subsequently, a crown must be
applied to completely cover the
restoration so that the prosthetic
margins are brought as close as possible to the dentin tissue, the load is
transferred better on the root, and
the possibilities of fracture through
the ferrule effect are reduced.1 However, teeth restored in this manner
often are subject to failure with core
detachment and post yielding; this
happens primarily when the crowns
supported by fiber posts are anchors
for removable partial dentures.2
During mastication loading,
stress is concentrated strongly at
the cervical zone, and mechanical
features of the fiber post are crucial
to establishing the restoration.1,3,4
For instance, post diameter or type
of post fiber can influence the value
of stiffness.1,5,6 Aird determined
that the stiffness varies according to
by type of post (p < 0.0001); single-tapered posts were weaker than
double-tapered posts. Pearson’s linear correlation test showed that
the fracture strength results appear to have a direct correlation to
the emerging diameter of the post (p < 0.0001; r2 = 0.6191).
The emerging diameter of fiber posts is important to stabilize the
core. When restoring crownless teeth, it is advisable to use fiber
posts with large emerging diameters; no additional preparation of
the internal root dentin is necessary to enlarge the post diameter.
Received: October 14, 2009
Accepted: February 15, 2010
the cube of the thickness, so if the
thickness is doubled, the resistance
to buckling increases eight times.7
Asmussen et al demonstrated that
an increase in diameter generally
increases the value of stiffness, while
additionally showing that the type
of fiber and resin used to fabricate
the post could change the stiffness.8
These findings indicate that different fiber posts could perform
differently from a mechanical
standpoint by changing the pattern
of stress distribution. The percentage
of fibers used also could influence
the stiffness value of fiber posts.9 The
aim of this study was to evaluate the
fracture strength of roots restored
with fiber posts with different shapes
and emerging cervical diameters. The
hypothesis was that wider fiber posts
would have higher fracture strength.
Materials and methods
Eighty single-rooted human teeth
(maxillary central incisors, canines,
and mandibular premolars) that
had not been previously submitted
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for endodontic treatment were
selected. The teeth were cleaned
with periodontal curettes, stored in
1.23% chlorexidine for two hours
for disinfection, and stored in water
at 37°C until use. All of the crowns
were sectioned using a diamond disc
under cooling, with the length of
specimens standardized at 16 mm.
The 80 specimens were allocated
into eight test groups (n = 10)
(Table 1). The canals of the
specimens were prepared at 10
mm, using the preparation burs of
each post system. After preparation, each root was embedded in a
plastic cylinder (height = 25 mm;
diameter = 12 mm) filled with
an epoxy resin (Araldite MY721,
Huntsman) as follows: The preparation bur of the post system was
placed inside the prepared root canal;
the bur (with the root) was attached
to an adapted surveyor, with the
long axes of the bur, specimen, and
cylinder parallel to each other and
perpendicular to the ground; and
the acrylic resin was prepared and
General Dentistry
March/April 2011
e67
endodontics Effect of different emerging diameters on the fracture strength of restored crownless teeth
Table 1. Fiber posts tested in this study.
Group
Emerging
diameter (mm)
1
1.08
2
1.14
3
1.24
4
1.46
5
1.00
6
1.20
7
1.30
8
Fiber post
Manufacturer
Features
Endo
Light-post
Recherches
Techniques
Dentaires (RTD)
Quartz fiber
Conic
Smooth surface
RTD
Quartz fiber
Double-taper
Smooth surface
Innotech SRL
Glass fiber
Parallel side
Macroretentions on the surface
Innotech SRL
Glass fiber
Conic-cylindrical
Macroretentions on the surface
D.T.
Light-post
Compaq
Premier
1.50
1.08 mm
1.14 mm
1.00 mm
1.20 mm
1.24 mm
1.30 mm
1.46 mm
1.50 mm
Fig. 1. Groups 1–4 are shown from left to right
in the top row, while Groups 5–8 are shown
from left to right in the bottom row.
Table 2. Results of one-way ANOVA test.
Source
Degree of freedom
Sum of square
Mean of square
F
P
7.17
<0.0001
7
258178
36882.6
Within
Between
72
370219
5141.9
Total
79
628397
poured inside the cylinder up to 3.0
mm of the most coronal portion of
the specimen (Fig. 1).
Post cementation
The fiber posts were etched with
32% phosphoric acid for one
minute, then rinsed and dried. For
root/crown dentin, a multiple-bottle
etch and rinse adhesive system (All
Bond 2, Bisco, Inc.) was used. Posts
were etched with 32% phosphoric
acid for 30 seconds, then washed
with 10 mL of water in a disposable
syringe. Excess water was removed
with No. 80 absorbent paper points.
Primer A and Primer B (All Bond
2) were mixed and applied to the
posts; excess material was removed
using a CaviTip brush (Directa
AB). Pre-Bond resin (All Bond 2)
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March/April 2011
was applied; excess material was
removed using a brush.
For post cementation, the A and
B pastes of a resin cement (DuoLink, Bisco, Inc.) were measured
and mixed. The cement was applied
to the post and root canal with a
No. 40 lentulo spiral (Dentsply
Maillefer). The top surface was
photocured for 40 seconds using an
XL 3000 unit (3M ESPE) at a light
intensity of 450 mW/cm2.
After post cementation, the core
was made with a hybrid composite resin (Light-Core, Bisco,
Inc.), using plastic matrixes that
were standardized in dimensions
(height = ±6.0 mm). The composite
was packed inside the matrix, which
then was positioned on the post
and the top surface of the tooth and
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www.agd.org
Fig. 2. Top: Fracture strength test. Bottom:
Specimen after testing.
photocured (XL 3000) for 20 seconds through the vestibular, lingual,
medial, and distal surfaces.
Fracture strength test
The specimens were placed in a
metallic base at a 45 degree angle
(to simulate clinical conditions
as closely as possible) so that a
Chart 1. Means and SDs of the
fracture strength data (N).
Table 3. Means (± SD) of the facture
strength results.
500
1
2
3
4
5
6
7
8
Emerging
Fracture
diameter (mm) strength (N)*
Endo
Light-Post
1.08
262.6 ± 81c
1.14
314.7 ± 35bc
D.T.
Light-Post
1.24
318.2 ± 69bc
Compaq
Premier
400
Fracture strength (N)
Group Fiber post
a
1.46
422.8 ± 56
1.00
269.2 ± 77c
1.20
334.4 ± 89abc
1.30
375.5 ± 72ab
1.50
414.6 ± 80ab
300
200
100
*Different superscript letters indicate a statistically significant
difference.
0
1
2
3
4
5
6
7
8
Group
Results
The one-way ANOVA showed that
fracture strength was affected by the
type of post (p < 0.0001) (Table 2).
Means and standard deviations
(Tukey’s test) are shown in Table 3
shown in Chart 1. In general, the
wider fiber post promoted higher
fracture strength values, but only
the D.T. Light-Posts (Groups 3 and
4) demonstrated statistically significant differences.
Pearson’s linear correlation
test demonstrated a direct correlation between fiber post diameter and fracture strength results
(p < 0.0001; r2 = 0.6191) (Chart 2).
Chart 2. Scatter plot of post diameter versus
fracture strength values (p < 0.0001; r2 = 0.6191).
550
470
Fracture strength (N)
point with a 1.6-mm diameter tip
from a universal testing machine
(Instron Corp.) could induce load
up to fracture. The maximum force
required to fracture was considered
to be the fracture strength (Fig.
2). One-way ANOVA and Tukey’s
tests were used to compare the
groups (α = 0.05), while Pearson’s
linear correlation test was used to
correlate the post diameter and
fracture strength results.
390
310
230
150
1.0
1.2
1.4
1.6
Diameter (mm)
Discussion
One advantage of fiber posts is a
modulus of elasticity (E = 30–40
GPa) similar to that of dentin
(E = 18 GPa), permitting a better
dissipation of masticatory loads
under clinical function.10-14
However, this low modulus of
elasticity permits greater flexion of
the fiber posts, producing tension
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at the interface of the post/resin
core, thus reducing the adhesive
resistance.15 A possible way to avoid
this deflexion could be to utilize a
post with a larger diameter at the
canal entrance, because maximum
equivalent stress occurs at the vestibular side of the cervical cement
layer (interface between post
and cement).16
General Dentistry
March/April 2011
e69
endodontics Effect of different emerging diameters on the fracture strength of restored crownless teeth
In the present study, it was
observed that the greater the post
diameter, the higher the fracture
strength of the dentin post and core
setup. Similarly, in 2004, Lassila
et al showed a linear increasing
resistance against loading force in
addition to an increase in diameter.6 Both carbon/graphite and
glass fiber-reinforced posts behaved
similarly. According the authors,
from a clinical perspective, this
suggests that thick posts contribute
more favorably than thin posts to
the fracture resistance of the rootpost-core-crown system.
The findings of the current
study also corroborate the results
obtained by Amaral et al in 2009.17
In that study, the fracture resistance
of teeth restored with fiber posts
with different cervical diameters
and surface characteristics (macroretentions) was tested; it was noted
that wider fiber posts promoted
higher fracture strength.
Another factor related to the
resistance of a restoration is the post
structure. A 2007 study tested the
hypothesis that the fiber diameter
and the surface occupied by fibers
per square millimeter of post surface
(fiber:matrix ratio) is directly related
to the physical properties of a fiber
post.18 This factor can explain the
differences between the two types of
posts used in the current study.
According to the methodology
used and the results, it is advisable to
use fiber posts with large emerging
diameters when restoring crownless
teeth; however, additional preparation of the internal root dentin is
not advisable for enlargement of
the fiber post diameter. Minimal
intervention is essential in restoring
crownless teeth. The results of the
current study suggest that a minimum diameter of 1.5 mm is key for
optimizing the clinical performance
of teeth restored with fiber posts.
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March/April 2011
Further studies should be conducted using mechanical fatigue
testing, especially to correlate the
increase of the fiber post diameter
and the weakening of the root.
Fatigue failure is a multi-stage
process involving creation of
microfractures at the interfaces,
growth and coalescence of microscopic flaws into dominant cracks,
and stable propagation of the
dominant macrofractures according
to the combination of open, tear,
and shear modes occurring in a
multi-axial stress condition. In this
manner, fatigue testing can simulate
masticator conditions.16
Conclusion
The findings of the present study
suggest that, in crownless teeth, fiber
posts with a wider cervical emerging
diameter can provide higher fracture
strength and a more mechanically
stable setup. Additional preparation
of the root dentin to increase the
post diameter is not advised.
Acknowledgements
The authors are grateful to the Control Quality Center of Basell Polyolefins SpA, Ferrara, Italy, for assistance
with the fracture strength tests.
Disclaimer
The authors have no relationship
with any of the manufacturers listed
in this article.
Author information
Dr. Baldissara is an assistant professor and researcher, Division of
Prosthodontics, Department of Oral
Science, Alma Mater Studiorum
University of Bologna, Italy. Dr.
Zicari is a graduate student, Department of Conservative Dentistry,
School of Dentistry, Leuven
University, Belgium. Dr. Valandro
is an associate professor, Division
of Prosthodontics, Department of
General Dentistry
www.agd.org
Restorative Dentistry, Federal University of Santa Maria, Santa Maria,
RS, Brazil.
References
1. Scotti R, Ferrari M. Fiber posts—Theoretical
considerations and clinical applications. Milan:
Masson;2002:39-51.
2. Malferrari S, Monaco C, Scotti R. Clinical evaluation of teeth restored with quartz fiber-reinforced epoxy resin posts. Int J Prosthodont
2003;16(1):39-44.
3. Pegoretti A, Fambri L, Zappini G, Bianchetti M.
Finite element analysis of glass fibre reinforced
composite endodontic post. Biomaterials 2002;
23(13):2667-2682.
4. Ukon S, Moroi H, Okimoto K, Fujita M, Ishikawa
M, Terada Y, Satoh H. Influence of different elastic moduli of dowel and core on stress distribution in root. Dent Mater J 2000;19(1):50-64.
5. Galhano GA, Valandro LF, de Melo RM, Scotti R,
Bottino MA. Evaluation of the flexural strength
of carbon fiber-, quartz fiber-, and glass fiberbased posts. J Endodont 2005;31(3):209-211.
6. Lassila LV, Tanner J, Le Bell AM, Narva K, Vallittu
PK. Flexural properties of fiber reinforced root
canal posts. Dent Mater 2004;20(1):29-36.
7. Aird F. Molds. In: Fiberglass and composite materials. New York: HP Books;1996:99-111.
8. Asmussen E, Peutzfeldt A, Heitmann T. Stiffness,
elastic limit, and strength of newer types of
endodontic posts. J Dent 1999;27(4):275-278.
9. Viguie G, Malquarti G, Vincent B, Bourgeois D.
Epoxy/carbon composite resins in dentistry: Mechanical properties related to fiber reinforcements. J Prosthet Dent 1994;72(3):245-249.
10. Akkayan B, Gulmez T. Resistance to fracture of
endodontically treated teeth restored with different post systems. J Prosthet Dent 2002;87(4):
431-437.
11. Cormier CJ, Burns DR, Moon P. In vitro comparison of the fracture resistance and failure mode
of fiber, ceramic, and conventional post systems
at various stages of restoration. J Prosthodont
2001;10(1):26-36.
12. Drummond JL, Toepke TR, King TJ. Thermal and
cyclic loading of endodontic posts. Eur J Oral Sci
1999;107(3):220-224.
13. Ottl P, Hahn L, Lauer HCH, Fay M. Fracture characteristics of carbon fibre, ceramic and non-palladium endodontic post systems at monotonously
increasing loads. J Oral Rehabil 2002;29(2):175183.
14. Pontius O, Hutter JW. Survival rate and fracture
strength of incisors restored with different post
and core systems and endodontically treated
incisors without coronoradicular reinforcement.
J Endodont 2002;28(10):710-715.
15. Qualtrough AJ, Mannocci F. Tooth-colored post
systems: A review. Oper Dent 2003;28(1):86-91.
16. Lanza A, Aversa R, Rengo S, Apicella D, Apicella
A. 3D FEA of cemented steel, glass and carbon
posts in a maxillary incisor. Dent Mater 2005;
21(8):709-715.
17. Amaral M, Favarin Santini M, Wandscher V, Villaca Zogheib L, Valandro LF. Effect of coronal
macroretentions and diameter of a glass-FRC
on fracture resistance of bovine teeth restored
with fiber posts. Minerva Stomatol 2009;58(3):
99-106.
18. Seefeld F, Wenz HJ, Ludwig K, Kern M. Resistance to fracture and structural characteristics
of different fiber reinforced post systems. Dent
Mater 2007;23(3):265-271.
Manufacturers
Bisco, Inc., Schaumburg, IL
800.247.3368, www.bisco.com
Dentsply Maillefer, Tulsa, OK
800.924.7393, www.maillefer.com
Directa AB, Upplands Varby, Sweden
46.8.506.505.75, www.directadental.com
Huntsman, The Woodlands, TX
888.564.9318, www.huntsman.com
Innotech SRL, Milan, Italy
333.67.47.911, www.innotechsrl.com
Instron Corp., Canton, MA
800.564.8378, www.instron.com
Recherches Techniques Dentaires (RTD),
Saint Egreve, France
33.4.76.56.56.66, www.rtd.fr
3M ESPE, St. Paul, MN
888.364.3577, www.3mespe.com
COMMENT
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General Dentistry
March/April 2011
e71
Implants
Using cone beam computed tomography
to determine safe regions for implant
placement
Sayde Sokhn, BDS, DUA, DUB
n
Ibrahim Nasseh, DCD, DSO, FICD
This study sought to identify and follow the course of the incisive
canal in the mental interforaminal region of the human mandible
and to describe other anatomical landmarks present in this region.
Cone beam computerized tomography (CBCT) studies for 40
patients were collected from the database at the Department
of Oral & Maxillofacial Radiology, School of Dentistry, Lebanese
University. Ten patients had edentulous mandibles; the other 30
had partially or completely dentate mandibles. Axial native images
and panoramic and cross-sectional reconstructions were examined
F
or most dental practitioners,
the use of advanced imaging
has been limited due to cost,
availability, and radiation dose considerations. Cone beam computed
tomography (CBCT) is capable of
providing submillimeter resolution
in images of high diagnostic quality, with short scanning times and
radiation dosages notably lower than
those of conventional CT scans.1
The introduction of CBCT for the
maxillofacial region provides opportunities for dental practitioners
to request the most advanced and
detailed images needed for adequate
diagnosis and treatment planning.
During surgical procedures in the
mandible, the mental interforaminal
region usually is considered to be a
safe region, with no significant risk of
damaging vital anatomical structures.
Common surgical procedures performed in this region include insertion of endosseous implants, bone
harvesting from the chin, genioplasty
in orthognatic surgery, and screwing
with or without plating after trauma
to the anterior mandible.
e72
March/April 2011
n
Marcel Noujeim, DDS, MS
to assess the anatomical landmarks in the anterior mandible.
Multiple neurovascular canals and foramina were clearly detected
on CBCT studies of the mandible. Numerous foramina were seen
on the internal surface of the mandible, even distant from the
midline. The incisive canal was identified in 97.5% of the images.
These anatomical landmarks should be evaluated carefully during
preoperative planning.
Received: March 8, 2010
Accepted: May 1, 2010
Even so, the precise anatomy of
the interforaminal region, with its
potential clinical implications, is
still controversial. The mandibular
incisive canal is described mainly as
a prolongation of the mandibular
canal anterior to the mental foramen (MF), containing a neurovascular bundle.2
The lingual foramen (LF) is usually situated in the midline of the
internal surface of the mandible
at the level of or superior to the
mental spines.3,4 The lingual canal
(LC) and LF are important considerations for surgical placement
of dental implants in this region.
The inferior alveolar artery provides
some branches to the medial portion of the mental region at the
anterior mandible and may pass
through the LC to the LF, where
they emerge to enter the mylohyoid or anterior belly of digastric
muscles. However, previous studies
have reported life-threatening conditions caused by profuse bleeding
following interforaminal implant
placement. If this complication
General Dentistry
www.agd.org
remains unnoticed during a surgical procedure, it could create an
upper airway obstruction due to the
development of a large hematoma
within the mouth floor. Surgical,
radiographic, and anatomical measures should be taken to prevent
severe bleeding and other complications during surgery.5-7
In addition, Tepper et al mentioned the existence of numerous
foramina on the internal surface
of the mandible, even distant from
the midline (premolar region).8
Unfortunately, the extent to
which these foramina play a role
in the neurovascular supply of the
mandible and/or teeth has not been
documented.
This study was designed to
evaluate the presence and course
of the incisive canal (IC), LF, and
innominate foramina in panoramic
and axial reconstructions generated
from CBCT data, and to discuss
their clinical significance. Many
studies neglect the presence of a
true IC and usually suggest that
placing dental implants in this
Lingual foramen
Incisive canal
h
MF
1 2 3
Fig. 1. Panoramic and cross-sectional reconstructions revealed an implant
situated in the IC. The patient had experienced pain and sensory disturbances
of the lower lip for three months.
region cannot cause damage to vital
anatomical structures; however, in
this study, patients who underwent
implant surgery in the incisive canal
demonstrated a neurosensory disturbance (Fig. 1).9,10
The aim of the present study was
twofold: to assess the appearance of
the IC and other anatomical landmarks (MF, LF, innominate foramina, and anterior looping) in the
mental interforaminal region on
CBCT images of patients referred
for implant placement in the
mandible; and to radiographically
establish the location and course of
the incisive canal, if present, and to
determine its dimensions (Fig. 2).
Materials and methods
This retrospective study included
mandibular CBCT images from
40 patients (26 women and 14
men) aged 20–60. Patients were
examined for mandibular implant
planning. Conventional panoramic
radiographs were available for
some patients. All CBCT volumes
were taken using a standard
exposure with an exposure time of
4
Lingual canal
w
d
d
Fig. 2. The course and location of the IC, with a cross-sectional schematic
drawing illustrating the IC, LF, and LC.
Fig. 3. A conventional panoramic image illustrating a well-defined anterior looping of the mental canal.
20 seconds and a voxel size of 0.3
mm. Panoramic reconstructions
were obtained with 0.3 or 0.4 mm
slice thicknesses. Reformatted
cross-sectional views were generated
as well, with 1.0 mm spacing.
Axial, coronal, and sagittal views
as well as the reconstructed images
were reviewed carefully for the presence and course of an anterior prolongation of the mandibular canal.
In addition, linear measurements
were performed.
www.agd.org
Results
Conventional panoramic radiographs
can be used to visualize the MF and
a potential anterior looping but not
to locate the mandibular IC (Fig. 3).
A portion of the IC was observed by
Jacobs et al in 11% of cases after the
anterior loop of the MF.11 CBCT
imaging modalities are preferred
to verify the existence of the IC for
preoperative planning purposes.
On CBCT images, the lingual
canal(s) and foramina were observed
General Dentistry
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Implants Using cone beam computed tomography to determine safe regions for implant placement
IC
LC
LF
MF
Fig. 5. A well-defined innominate foramina situated
between the MF and LF with a large (significant) diameter,
cross-sectional numbers 72 and 105. (The number of the crosssectional image is indicated in the panoramic reconstruction.)
Fig. 4. Cross-sectional images illustrating the MF, LF, and LC.
Fig. 6. The structure of bony walls recorded as complete bony cortical
walls.
in 97.5% of the cases. The MF could
be seen in 100% of the cases (Fig. 4).
The innominate foramina was identified in three patients; it is symmetrical and has a diameter of 1.6 ± 1.0
mm (Fig. 5). The IC was observed in
97.5% of the cases, with a diameter
ranging from 0.45–2.9 mm.
The structure of the bony walls
was recorded as follows: Complete
bony cortical walls throughout
the canal (25% of cases) (Fig. 6);
cortical bony borders and areas
of medullary bone in part of the
canal (60% of cases) (Fig. 7); and
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March/April 2011
Fig. 7. The structure of bony walls recorded as cortical bony borders and
areas of medullary bone in part of the canal.
no cortical walls observed, and the
bundle traveling through the medullar bone (15% of cases) (Fig. 8).
Discussion
The inferior alveolar nerve runs an
entirely intraosseous course from its
entry into the mandibular canal at
the mandibular foramen. The nerve
is accompanied in the mandibular
canal by the inferior alveolar artery,
a branch of the maxillary artery.
These neurovascular structures
supply the teeth and periodontium
on both sides of the mandibular
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arch. At the MF, the inferior alveolar nerve and inferior alveolar artery
diverge from the mental nerve
and mental artery, respectively, to
supply and innervate the skin of
the lower lip, the alveolar mucosa,
and the gingiva as far posterior as
the second premolars. The incisive
nerve has been described as one of
the terminal branches of the inferior
alveolar nerve and appears to run in
a clearly defined IC in the mental
interforaminal bone.2,3,12,13
Olivier was the first to describe
the course of the incisive nerve as a
continuation of the inferior alveolar
nerve traveling in a canal or through
the vacuoles of the spongy bone.14
The observations of Mardinger et
al and Bavitz et al strengthened
this theory.12,15 Mardinger et al
anatomically observed an IC in
80% of mandibles.12 Other studies,
however, did not detect the presence
of a true IC.9,10
The present study confirmed the
existence of the IC, as it was visible
in 97% of the cases. The present
findings also are in accordance with
the results from a CT scan observational study.2 They also support
the results reported by Mraiwa et al,
Bavitz et al, and Uchida et al.3,15,16
No difference was noted between
the widths of the IC in edentulous
or dentate subjects in this or other
studies.13 The diameter of the IC
appears to be large enough to support the presence of a neurovascular
bundle. In the present study, the
diameter of the IC was 0.45–2.9
mm, which is in agreement with
other studies.2,16 However, it should
be noted that the IC does not
appear unless the thickness of the
panoramic reconstruction is smaller
than the diameter of the IC (Fig. 9).
The presence of a well-defined LF
on the midline of the lingual aspect
of the mandible was confirmed in
the present study, as an LF could be
seen in a majority of cases. Because
of the two-dimensional projection
of intraoral radiographs, the LF is
often perceived between the mental
spines. McDonnell et al investigated
the radiographic appearance of the
canal and concluded that the radiopaque rim is caused by the lingual
canal wall, not the mental spines.17
That group also found that periapical radiographs do not always depict
the LF and LC, depending on the
projection geometry. When the
X-ray beam is parallel to the canal,
visualization may be more likely.
Fig. 8. The structure of bony walls recorded as no corticals walls observed.
Fig. 9. The IC did not appear in the panoramic reconstruction if the thickness exceeded the diameter
of the canal.
Jacobs et al added that conventional radiography often fails to
demonstrate the presence of the LF,
due not only to technical limitations
of the image but also to observer limitations.18 Indeed, observers require
certain skills and knowledge of basic
information to recognize anatomical
landmarks such as the LF. The fact
that such features are not described
in anatomy textbooks could prevent
clinicians from gaining knowledge
regarding these structures.
www.agd.org
In contrast to two-dimensional
imaging, CT scans have the
advantage of not being sensitive to
beam orientation. For this reason, it
was easier to visualize the superior
and inferior genial spinal foramina
and their bony canals with CT
scans than has been reported
with conventional radiographic
results. Hofschneider et al were the
first to mention the possibility of
visualizing bone canals by means
of CT scans.19 Tepper et al and
General Dentistry
March/April 2011
e75
Implants Using cone beam computed tomography to determine safe regions for implant placement
Gahleitner et al also clearly demonstrated the high incidence of such
bone canals.20,21
The visualization on CT scans
reported by Liang et al (81%) actually is lower than what has been
reported during anatomical studies.5
This may be related to the reformatting procedure, with some CT scans
lacking a reformatted cross-sectional
slice exactly at the mandibular
midline. Also, it is possible that
the 1.0 mm slice thickness masked
smaller diameter structures on the
mandibular midline.12,16
CBCT is the most advantageous
technique for visualizing the IC.
Visibility of this canal in twodimensional images (such as intraoral and panoramic radiographs)
is limited and dependent on the
projection geometry, in addition
to other factors such as degree of
cortication of the canal wall. The
anatomical variations in this region
can be detected in the majority of
reconstructions from CBCT. The
findings from the present study are
in agreement with other anatomical
reports on the occurrence of multiple innominate foramina, LCs,
and lingual foramina.5,7,8
Anatomical features and variations should be considered during
surgical procedures in the mandible, such as during placement
of endosseous implants. Whether
neural and/or vascular structures
are present in the IC and LF is
the subject of further research;
however, based on the results of
the present study, it can be stated
that a well-defined IC appears to
be an intraosseous extension of the
inferior alveolar canal, so any surgical procedure could be considered
to present a risk of traumatizing a
neurovascular bundle. Doing so
could result in sensory disturbances
caused by direct trauma to the
incisive canal bundle.
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March/April 2011
In a case in which a patient had
pain and discomfort resulting
from implant placement in the
interforaminal region, postoperative CBCT images revealed
that implants were placed through
a large lumen of the IC (Fig. 1).
Sensory disturbances also could be
related to indirect trauma to the
IC bundle, causing a hematoma in
a closed chamber, spreading to the
main mental branch and resulting
in neurosensory disturbances.
Sensory disturbances of the
lower lip have also been reported.
These could be the result of direct
trauma to the anterior looping of
the mental nerve during implant
site preparation, especially when
implants are placed adjacent to
the MF or after bone harvesting
from the chin. It is possible that an
implant could fail to integrate in a
gap of 2.0 mm, the average diameter
of the IC.22 Rosenquist found that
the incisive bundle caused implant
failure by migration of soft tissue
around the implant, preventing
osseointegration.23
With the increased interest in
developing a thorough operative
plan prior to oral implant surgery
in the anterior mandible, crosssectional images may be considered
for obtaining more detailed
information about the appearance,
location, and course of the foramina
and canals and their relation to
other anatomical structures in
the mandible. CBCT may be the
preferred option when a balance is
needed between requirements for
quality and information on one
hand and costs and radiation doses
on the other.24
Conclusion
CBCT has changed the way clinicians approach dental diagnosis and
treatment planning, particularly
when knowledge of the anatomy
General Dentistry
www.agd.org
of the maxillofacial complex is
essential. CBCT has enabled dental
professionals to better visualize the
anatomy of the IC. Whether clinicians are looking at the position of
the IC with respect to the anteroinferior teeth or treatment planning
for implants, viewing the mandible
in all three dimensions helps to
extract the maximum information
needed for diagnosis and treatment.
The present study confirms that the
recent advances in imaging equipment and technology have increased
the applicability of cross-sectional
and panoramic reconstructions for
visualization of critical structures
prior to surgery.
Author information
Dr. Sokhn is a clinical instructor
in the Department of Oral and
Maxillofacial Radiology, School
of Dentistry, Lebanese University,
Beirut, Lebanon, where Dr.
Nasseh is professor and chair. Dr.
Noujeim is an assistant professor
and Program Director, Oral and
Maxillofacial Radiology, University
of Texas Health Science Center, San
Antonio, Texas.
References
1. Hashimoto K, Kawashima S, Kameoka S, Honjoya T, Ejima K, Sawada K. Comparison of image
validity between cone beam computed tomography for dental use and multidetector row helical computed tomography. Dentomaxillofac
Radiol 2007;36(8):465-471.
2. Jacobs R, Mraiwa N, van Steenberghe D, Gijbels
F, Quirynen M. Appearance, location, course,
and morphology of the mandibular incisive canal: An assessment on spiral CT scan. Dentomaxillofac Radiol 2002;31(5):322-327.
3. Mraiwa N, Jacobs R, Moerman P, Lambrichts I,
van Steenberghe D, Quirynen M. Presence and
course of the incisive canal in the human mandibular interforaminal region: Two-dimensional
imaging versus anatomical observations. Surg
Radiol Anat 2003;25(5-6):416-423.
4. Monsour PA, Dudhia R. Implant radiography
and radiology. Aust Dent J 2008;53 Suppl
1:S11-S25.
5. Liang X, Jacobs R, Lambrichts I. An assessment
on spiral CT scan of the superior and inferior
genial spinal foramina and canals. Surg Radiol
Anat 2006;28(1):98-104.
6. Kawai T, Asaumi R, Sato I, Yoshida S, Yosue T.
Classification of the lingual foramina and their
bony canals in the median region of the mandible: Cone beam computed tomography observations of dry Japanese mandibles. Oral Radiol
2007;23(2):42-48.
7. Yoshida S, Kawai T, Okutsu K, Yosue T, Takamori
H, Sunohara M, Sato I. The appearance of foramen in the internal aspect of the mental region
of the mandible from Japanese cadavers and
dry skulls under macroscopic observation and
three-dimensional CT images. Okajimas Folia
Anat Jpn 2005;82(3):83-87.
8. Tepper G, Hofschneider UB , Gahleitner A, Ulm
C. Computed tomography diagnosis and localization of bone canals in the mandibular interforaminal region for prevention of bleeding
complications during implant surgery. Int J Oral
Maxillofac Implants 2001;16(1):68-72.
9. Romanos GE, Greenstein G. The incisive canal.
Considerations during implant placement: Case
report and literature review. Int J Oral Maxillofac Implants 2009;24(4):740-745.
10. Polland KE, Munro S, Reford G, Lockhart A, Logan G, Brocklebank L, McDonald SW. The mandibular canal of the edentulous jaw. Clin Anat
2001;14(6):445-452.
11. Jacobs R, Mraiwa N, Van Steenberghe D, Sanderink G, Quirynen M. Appearance of the mandibular incisive canal on panoramic radiographs.
Surg Radiol Anat 2004;26(4):329-333.
12. Mardinger O, Chaushu G, Arensburg B, Taicher
S, Kaffe I. Anatomic and radiologic course of the
mandibular incisive canal. Surg Radiol Anat
2000;22(3-4):157-161.
13. Rouviere H, Delmas A. Anatomie humaine. Tome
I, ed. 15. Paris: Masson;2002.
14. Olivier E. The inferior dental canal and its nerve
in the adult. Br Dent J 1928;49:356-358.
15. Bavitz JB, Harn SD, Hansen CA, Lang M. An anatomical study of mental neurovascular bundleimplant relationships. Int J Oral Maxillofac
Implants 1993;8(5):563-567.
16. Uchida Y, Yamashita Y, Goto M, Hanihara T.
Measurement of anterior loop length for the
17.
18.
19.
20.
21.
22.
23.
24.
mandibular canal and diameter of the mandibular incisive canal to avoid nerve damage when
installing endosseous implants in the interforaminal region. J Oral Maxillofac Surg 2007;65
(9):1772-1779.
McDonnell D, Reza Nouri M, Todd ME. The mandibular lingual foramen: A consistent arterial
foramen in the middle of the mandible. J Anat
1994;184(3):363-369.
Jacobs R, Wu CH, Van Loven K, Desnyder M,
Kolenaar B, Van Steenberghe D. Methodology of
oral sensory tests. J Oral Rehabil 2002;29(8):
720-730.
Hofschneider U, Tepper G, Gahleitner A, Ulm C.
Assessment of the blood supply to the mental
region for reduction of bleeding complications
during implant surgery in the interforaminal region. Int J Oral Maxillofac Implants 1999;14(3):
379-383.
Tepper G, Hofschneider UB, Gahleitner A, Ulm C.
Computed tomographic diagnosis and localisation of bone canals in the mandibular region for
prevention of bleeding complication during implant surgery. Int J Oral Maxillofac Implants
2001;16(1):68-72.
Gahleitner A, Hofschneider U, Tepper G, Pretterklieber M, Schick S, Zauza K, Watzek G. Lingual
vascular canals of the mandible: Evaluation with
dental CT. Radiology 2001;220(1):186-189.
Uchida Y, Noguchi N, Goto M, Yamashita Y,
Hanihara T, Takamori H, Sato I, Kawai T, Yosue T.
Measurement of anterior loop length for the
mandibular canal and diameter of the mandibular incisive canal to avoid nerve damage when
installing endosseous implants in the interforaminal region: A second attempt introducing
cone beam computed tomography. J Oral Maxillofac Surg. 2009;67(4):744-750.
Rosenquist B. Is there an anterior loop of the
inferior nerve? Int J Periodont Rest Dent 1996;
16(1):40-45.
Pires CA, Bissada NF, Becker JJ, Kanawati A,
Landers MA. Mandibular incisive canal: Cone
beam computed tomography. Clin Implant Dent
Relat Res 2009;Aug 6.
COMMENT
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General Dentistry
March/April 2011
e77
oral Diagnosis
Recurrence of central odontogenic fibroma:
A rare case
Auremir Rocha Melo, DDS, MSc Thiago de Santana Santos, DDS, MSc
Marcelo Fernando do Amaral, DDS, MSc Davi de Paula Albuquerque, DDS
EmanuelSaviodeSouzaAndrade,DDS,MSc,PhD Edwaldo Dourado Pereira Jr., DDS, MSc, PhD
n
n
n
Central odontogenic fibroma (COF) is a rare, benign, painless,
slow-growing tumor associated with expansion of the bone cortex.
Histologically, it consists of fibrous connective tissue that contains
multiple islands of odontogenic epithelium. Some lesions have diffuse
spherical calcifications that usually are related to islands or cords of
epithelium. The majority of cases respond well to conservative treat-
T
he World Health Organization (WHO) defines central
odontogenic fibroma (COF) as
a benign tumor originating from
the odontogenic ectomesenchyma,
characterized by fibrous tissue with
variable cellularity and density, a
variable quantity of apparently inactive odontogenic epithelium, and
the presence of calcifications similar
to dysplastic dentin, cementum,
or bone.1 COF occurs only in jaw
bones and accounts for 0.1–5% of
all tumors of odontogenic origin.1,2
COF occurs in similar proportions in the anterior region of the
maxilla and the posterior region of
the mandible.3 It can be a small,
asymptomatic tumor or it can reach
large proportions that cause bone
expansion. An association with
impacted teeth occurs in one-third
of the cases. COF occurs more
frequently between the second and
fourth decades of life, but it has been
reported in children and the elderly.3
The radiographic image of the
tumor can be either unilocular or
multiocular and either radiolucent
or mixed, depending on the amount
of mineralized material; the margins
are well-defined.4 COF must be
e78
March/April 2011
ment such as enucleation and the prognosis is favorable; recurrences
are rare. This article presents a rare case of COF that was located in
the anterior region of the maxilla and treated with enucleation; the
case recurred five years following the initial treatment.
Received: January 21, 2010
Accepted: April 26, 2010
differentiated from other odontogenic tumors or even endodontic
lesions. Although the tumor does not
have a capsule, its growth is limited,
which favors its complete removal
through enucleation and rigorous
curettage. Recurrences are rare and
the prognosis is very favorable.
This article presents a rare case of
COF located in the anterior region
of the maxilla that was treated with
enucleation; the tumor recurred five
years following the initial treatment.
Case report
The tumor was removed whole and
had a rubbery, gelatinous aspect.
The impacted maxillary right
canine was maintained in the site,
with no bone coverage of the incisal
portion of the crown. The diagnosis
determined by histopathological
analysis was odontogenic fibroma.
Five years later, the patient noticed
a new increase in volume that was
progressing slowly in the same
region, so he returned to the same
oral maxillofacial surgery unit.
The extraoral examination of
the head and neck revealed no
A 16-year-old boy sought treatment at the Oral Maxillofacial
Surgery Unit of the Hospital Geral
de Areias in Recife, Brazil, complaining of a painless increase in
gingival volume in the region of the
maxillary right canine (Fig. 1). The
patient was in good health, with
no allergies to medications and no
relevant medical history.
Approximately five years earlier,
the patient underwent a surgical
procedure to remove a tumor from
the same site. The description of
the surgery reported that the procedure was performed under local
anesthesia without complications.
Fig. 1. Intraoral image of a swelling in the
buccal region of the maxillary right canine
and the presence of a primary maxillary right
lateral incisor.
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Fig. 2. Panoramic radiograph demonstrating the presence of the maxillary right
canine.
abnormalities. The intraoral examination revealed an increased volume
of the vestibular cortex in the
region of the maxillary right canine
extending to the region of the right
lateral incisor and first premolar.
The mass had a hard, nonfloating
consistency, was painless on palpation, and was covered by mucosa
with normal texture and coloration.
Aspiration was negative for liquids,
suggesting a solid lesion. The
radiographic examination revealed
an impacted maxillary right canine
and a poorly defined radiotransparent unilocular tumor between the
canine and the primary lateral
incisor, apparently without the
involvement of the apical region of
these teeth (Fig. 2 and 3).
After incison and mobilization of
the total thickness of the flap, the
vestibular bone cortex was removed,
the maxillary right canine and the
primary maxillary lateral incisor
were extracted, and a tumor of a
gelatinous aspect was removed in
fragments. Peripheral ostectomy was
performed with a high-speed drill
under abundant irrigation.
A photomicrograph of the tumor
revealed islands of odontogenic
Fig. 3. Maxillary oclusal radiograph. Note the ill-defined
radiolucent image related to the maxillary right canine and the
primary maxillary right lateral incisor.
epithelium that at times were inactive and at times deposited a mineralized intracellular matrix similar to
that of cementum or bone (Fig. 4).
The presence of hypercellularized
connective tissue with intensive
deposition of complete collagen
fibers confirmed the diagnosis of
odontogenic fibroma (WHO type).
The patient has made follow-up
visits for three years with no clinical
signs of recurrence.
Discussion
Fig. 4. Odontogenic fibroma characterized by
a matrix of fibrous connective tissue showing
islands and cords of inactive odontogenic
epithelium. Several foci of calcification are seen
in odontogenic epithelium islands (H&E stain;
magnification 100x).
COF is a rare tumor. Older studies
attribute a 23% frequency to COF
due to interpretations that hyperplastic dental follicles represented
cases of odontogenic fibroma.2
A large number of publications
report isolated occurrences with
the peculiarities or specificities of
each case.5-7 The two largest series
published consisted of 24 and 19
cases.8,9 For this reason, it is not
possible to obtain concrete data on
the epidemiology of this condition
or reach conclusions regarding its
treatment and prognosis.
The age at which COF has been
diagnosed varies considerably in
the literature, ranging from 5–80.1,6
The most frequently encountered
clinical characteristics are a painless
increase in volume that progresses
slowly, covered by mucosa that
appears normal.7,9 The clinical
characteristics of the patient in the
present case report matched those
described in the literature.
The radiographic aspect of
COF varies from case to case, but
it is commonly characterized as
a unilocular radiolucent tumor
(55%) with well-defined edges
(73.3%).1,3,6 Although calcifications
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General Dentistry
March/April 2011
e79
oral Diagnosis Recurrence of central odontogenic fibroma
Table. Characteristics of WHO-type COF recurrences.
Author
Heimdal et al (1980)
Svirsky et al (1986)
Jones et al (1989)
Kinney et al (1993) Present case
Patient age
20
45
51
66
16
Gender
Female
Female
Female
Female
Male
Site
Apex of the mandibular
left first molar
Right mandible
between the first
and second premolar
Mandibular symphysis
Apex of the
mandibular right
second molar
Between the maxillary right
canine and the primary right
lateral incisor
Initial
treatment
Enucleation; extraction
of related tooth
Curettage
Curettage
Enucleation;
extraction of
related tooth;
curettage
Enucleation
Recurrence
Nine years
Two years
16 months
One year
Five years
are determined through histological analysis in approximately 19%
of cases, they are not always seen
in the radiograph. Small tumors
generally have a unilocular image,
while larger tumors may have a
multilocular aspect.
Radiographic characteristics
of COF can be similar to those
exhibited by other conditions, such
as periapical tumor, traumatic bone
cyst, odontogenic cyst, central
giant cell tumor, ameloblastoma,
and myxoma.4,7 Pathologists unfamiliar with odontogenic tissues
and tumors could have difficulty
distinguishing COF from other
odontogenic tumors and normal
components of odontogenesis. The
predilection for the anterior region
of the maxilla diverges from many
other odontogenic tumors, which
tend to affect the region of the third
molars, and is an important data
point for the differential diagnosis
of this tumor.9 The tumor has no
adherence to adjacent bone and
tooth structures, which favors conservative treatment.7
Although rare, recurrences can
occur. The first was reported by
Heimdal et al in 1980.10 Since then,
three other cases of recurrence of
WHO-type COF and three cases of
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March/April 2011
recurrence of COF with a giant cell
granuloma component have been
published.5,11-14 The table illustrates
the lack of common characteristics
that would allow for the identification of a more aggressive pattern or
the prediction of recurrence. Errors
in the histological diagnosis of the
tumor and inadequate surgical
techniques are considered to be
possible causes of recurrence.6,12
A probable explanation for the
recurrence in the case reported here
would be the maintenance of the
impacted maxillary right canine
and its periodontal ligament as a
reactivating factor for the tumor.
Andrade is a professor, Department
of Oral and Maxillofacial Pathology, and Dr. Pereira is a professor,
Department of Oral and Maxillofacial Surgery. Dr. Santos is also a
postgraduate student, Department
of Oral and Maxillofacial Surgery,
University of Sao Paulo (FORP/
USP), Ribeirao Preto, SP, Brazil. Dr.
Amaral is a postgraduate student,
Department of Oral and Maxillofacial Surgery, Federal University
of Pernambuco (UFPE), Recife,
PE, Brazil. Dr. Albuquerque is a
specialist, Department of Oral and
Maxillofacial Surgery, Hospital of
the Restoration, Recife, PE, Brazil.
Summary
References
The findings of this study underline
the importance of follow-up and
periodic clinical and radiographic
examinations for COF. The majority
of cases respond well to conservative
treatment such as enucleation and
the prognosis is favorable; recurrences are rare.
Author information
Drs. Melo and Santos are postgraduate students, Department of
Oral and Maxillofacial Surgery, University of Pernambuco (FOP/UPE),
Camaragibe, PE, Brazil, where Dr.
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1. Brannon RB. Central odontogenic fibroma,
myxoma (odontogenic myxoma, fibromyxoma),
and central odontogenic granular cell tumor.
Oral Maxillofac Surg Clin North Am 2004;
16(3):359-374.
2. Daniels JS. Central odontogenic fibroma of
mandible: A case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod 2004;98(3):295-300.
3. Kaffe I, Buchner A. Radiologic features of central odontogenic fibroma. Oral Surg Oral Med
Oral Pathol 1994;78(6):811-818.
4. Huey MW, Bramwell JD, Hutter JW, Kratochvil FJ.
Central odontogenic fibroma mimicking a lesion
of endodontic origin. J Endod 1995;21(12):625627.
5. Kinney LA, Bradford J, Cohen M, Glickman RS.
The aggressive odontogenic fibroma: Report of
a case. J Oral Maxillofac Surg 1993;51(3):321324.
6. Cercadillo-Ibarguren I, Berini-Aytes L, MarcoMolina V, Gay Escoda C. Locally aggressive central odontogenic fibroma associated to an
inflammatory cyst: A clinical, histological and
immunohistochemical study. J Oral Pathol Med
2006;35(8):513-516.
7. Silva CO, Sallum AW, do Couto-Filho CE, Costa
Pereira AA, Hanemann JA, Tatakis DN. Localized
gingival enlargement associated with alveolar
process expansion: Peripheral ossifying fibroma
coincident with central odontogenic fibroma. J
Periodontol 2007;78(7):1354-1359.
8. Fowler C, Tomich C, Brannon R, Houston G. Central odontogenic fibroma: Clinicopathologic features of 24 cases and review of the literature
[abstract]. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod 1993;76:587.
9. Handlers JP, Abrams AM, Melrose RJ, Danforth
R. Central odontogenic fibroma: Clinicopathologic features of 19 cases and review of the
literature. J Oral Maxillofac Surg 1991;49(1):
46-54.
10. Heimdal A, Isacsson G, Nilsson L. Recurrent central odontogenic fibroma. Oral Surg Oral Med
Oral Pathol 1980;50(2):140-145.
11. Svirsky JA, Abbey LM, Kaugars GE. A clinical
review of central odontogenic fibroma: With the
addition of three new cases. J Oral Med 1986;
41(1):51-54.
12. Jones GM, Eveson JW, Shepherd JP. Central
odontogenic fibroma. A report of two controversial cases illustrating diagnostic dilemmas. Br J
Oral Maxillofac Surg 1989;27(5):406-411.
13. Allen CM, Hammond HL, Stimson PG. Central
odontogenic fibroma, WHO type. A report of
three cases with an unusual associated giant
cell reaction. Oral Surg Oral Med Oral Pathol
1992;73(1):62-66.
14. Odell EW, Lombardi T, Barrett AW, Morgan PR,
Speight PM. Hybrid central giant cell granuloma
and central odontogenic fibroma-like lesions of
the jaws. Histopathology 1997;30(2):165-171.
COMMENT
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General Dentistry
March/April 2011
e81
Dental Materials
Flexural bond strength of repaired
composite resin restorations:
Influence of surface treatments and aging
Angela Alexandre Meira Dias, DDS, MSD Marcos Oliveira Barceleiro, DDS, MSD, PhD
RogerioLuizOliveiraMussel,DDS,MSS,PhD Helio Rodrigues Sampaio-Filho, DDS, MSD, PhD
n
n
The objective of this study was to evaluate the effect of storage
in deionized water at room temperature, for seven days and
six months, on the flexural strength of a repaired photocured
microhybrid composite resin, using different surface treatments.
After each surface treatment, the adhesive interface was analyzed
with a surface roughness tester. The flexural strength of samples
from each group was determined by three-point bending in a
testing machine at a crosshead speed of 0.5 mm/min with a 50
N load cell. Data were analyzed using ANOVA ( p = 0.0001) and
compared with the Newman-Keuls multiple comparison test.
It was verified that flexural strength of the unrepaired specimens,
C
omposite resin materials and
adhesive techniques have
become the basis of modern
restorative dentistry. The clinical
application of composite resins
encompasses everything from the restoration of the initial caries process
and cosmetic corrections through
full prosthetic rehabilitation.1
Current adhesive techniques allow
dental preservation because only the
carious areas are removed during
dental preparation. It is recognized,
however, that composite resins have
both inconvenient and attractive
properties as a restorative material.
Despite recent significant
improvements in composite resin
restoration resistance, problems still
exist regarding wear, color change,
fracture, and superficial pigmentation over time.2-4 However, when an
existing composite resin restoration
presents a defect, it is not always
necessary to replace it; sometimes a
repair can be made.5-7
e82
March/April 2011
after both seven days and six months, was similar ( p > 0.05) and
was in accordance with ISO specifications (minimum of 50 MPa),
with values ranging from 52–63 MPa. The authors concluded that
the use of an unfilled resin agent is necessary prior to the repair to
increase the adhesive strength. Further, the use of a silane agent
prior to use of the unfilled resin agent is unnecessary, since it does
not increase the adhesive strength.
Received: September 30, 2009
Last revisions: January 8, 2010
Accepted: February 15, 2010
Current knowledge of the
biological risks of restorative materials requires reflection on repair
techniques. The interfacial adhesive
resistance of repaired restorations
is clearly affected by some factors,
including the age of the initial
layer; superficial condition of the
initial layer; cure; contamination of
the surface of the initial layer with
saliva; use of an adhesive agent; use
of both a silane and an adhesive
agent; characteristics of the resinous adhesive agent when applied,
mainly its viscosity and wetting;
composite viscosity; particle load of
the composite; and time of storage
of repaired specimens in water.8-16 A
variety of superficial mechanical and
chemical treatments have improved
the adhesive strength between old
and new composite layers.
The purpose of the current study
was to evaluate the effect on flexural
strength of photocured microhybrid
composite resin TPH Spectrum
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(Dentsply Caulk) restorations,
repaired using different surface
treatments and stored in deionized
water at room temperature for seven
days and six months.
Materials and methods
Specimen preparation
Control group (Group 1)
All specimens were prepared using
a stainless steel split mold that was
25 mm long, 2.0 mm wide, and 2.5
mm deep. Each specimen, protected
by a polyester matrix, was polymerized three times, once from above
and once from each side. Each application lasted 40 seconds and used a
device (Optilight 600, Gnatus) that
emitted a light intensity between
400 mW/cm2 and 500 mW/cm2, as
verified by a radiometer.
After initial polymerization,
the 30 control specimens were
stored in distilled and deionized
water in a black container at room
temperature for seven days. Silicon
sandpaper with grits ranging from
320–600 was used to prepare
specimens to dimensions of 25
mm long, 2.0 mm thick, and 2.0
mm wide. Fifteen specimens were
randomly chosen for roughness
testing after one week, while the
remaining 15 were kept in storage
under the same conditions for six
months, with the water changed
every seven days.
Test groups
The same stainless steel split mold
that had been used for the control
group was used to create 120
repaired specimens. However, the
central depression was one-third
filled, then immersed in distilled
and deionized water for seven days.
Next, the specimens were marked
with a pencil at a length of 12.5
mm, where the surface treatments
were applied before repairing. The
preparation protocol for each test
group is described below.
DIAMOND BUR MECHANICAL TREATMENT
(GROUP 2)
A 4138 medium grit diamond
bur (KG Sorensen), adapted in
a SUPERtorque turbine (KaVo
America Corporation), was used
five times under water cooling. The
specimens then were dried by air
spurts and placed in the depression
of the stainless steel split mold to
receive the resin repair.
PHOSPHORIC ACID TREATMENT (GROUP 3)
These specimens received the
diamond bur mechanical treatment, then were conditioned with
37% phosphoric acid (Denstsply
International) for one minute and
washed under flowing water for
two minutes. The specimens then
were dried by oil- and water-free air
spurts and placed in the depression
of the stainless steel split mold to
receive the resin repair.
TREATMENT WITH RESINOUS ADHESIVE
(GROUP 4)
These specimens received the
diamond bur mechanical treatment
and the phosphoric acid treatment.
Next, two layers of Prime & Bond
2.1 adhesive (Dentsply Caulk)
were applied, using the provided
applicator tips, for 30 seconds. The
surfaces then were dried with light
water- and oil-free air spurts for
five seconds and polymerized for
10 seconds. The specimens then
were placed in the stainless steel
split mold to receive the resin repair.
SILANE TREATMENT (GROUP 5)
These specimens received the
diamond bur mechanical treatment
and the phosphoric acid treatment.
Next, the specimens received a
silane layer, prepared with a drop
from Silane Primer (Dentsply
International) mixed with a drop of
Silane Activator (Dentsply International) in a special receptacle. After
five minutes, the silane treatment
was applied, using applicator tips,
in two fine layers on the surface
to be repaired, then air-dried. The
specimens then received two layers
of Prime & Bond 2.1 adhesive
for 30 seconds. The surfaces were
dried with light spurts of air for
five seconds and polymerized for
10 seconds. The specimens then
were placed in the stainless steel
split mold to receive the resin repair.
results used to calculate the effect
of storage in water and the action of
the mechanical and chemical treatments made before repairing.
Flexural strength was evaluated
according to ISO 4049. The specimens were tested on a computercontrolled universal testing machine
(DL 500, EMIC Ltd.) at a crosshead speed of 0.5 mm/min with
a 50 N load using a chisel-shaped
tool 1.0 mm thick and 10 mm in
length. The specimens were taken to
an aluminum device on the table of
the universal testing machine, with
20 mm between supports, which
was programmed to provide compression in the center of the specimen until it ruptured. Data were
transmitted to a dedicated computer
with a special program (TESC version 1.8, EMIC Ltd.) and tabulated
for later statistical analysis.
Results
The compressive strength results for
the seven-day and six-month groups
and their respective subgroups
(adhesive methods) are presented in
Table 1 and Chart 1. For both time
frames, Groups 2 and 3 showed
statistically significant differences
in relation to the other groups
(p < 0.001), although they did not
differ from each other. When comparing the seven-day and six-month
specimens, there was a statistically
significant difference between
Groups 2 and 3 (p < 0.001).
Surface roughness and flexural
strength analyses
Discussion
A previously calibrated surface
roughness tester (SJ-201P, Mitutoyo
America) was used to perform 10
readings on each specimen. This
was regulated to cover a distance
of 0.3 mm, scaled in micrometers
(μm). The average surface roughness (R a) was measured in micrometers and the data were compared
using ANOVA, with the tabulated
The thorough removal of a composite resin restoration is not always
necessary or desirable.17 The advantages of repairing a composite resin
restoration include increasing the
restoration’s longevity, reduced cost,
and less pulpal trauma.7,18-20 Repairs
can be conducted in cases of fracture, discoloration, old restorations
with a rough surface, marginal
www.agd.org
General Dentistry
March/April 2011
e83
Dental Materials Flexural bond strength of repaired composite resin restorations
Table 1. Compressive strength analysis according to time (seven days and
six months). Statistical differences were verified via one-way ANOVA and
Newman-Keuls post-hoc tests.
Mean value ± SD (MPa)
Group
1 (control)
Seven days
Six months
Statistical difference
( p < 0.05)
57 ± 9.4
57 ± 6.30
No
2
22 ± 3.1
1.7 ± 0.78
Yes
3
23 ± 3.2
1.9 ± 0.49
Yes
4
53 ± 5.0
57 ± 4.60
No
5
54 ± 5.9
53 ± 7.00
No
Chart 1. Mean (± SD) compressive strength values (in MPa)
at both time intervals. Different letters indicate a statistically
significant difference (p < 0.05).
70
a
Seven weeks
Compressive strength (MPa)
60
Six months
a
a
a
a
a
4
5
50
40
30
b
b
20
10
0
1
2
3
4
5
1
c
c
2
3
Group
defects or secondary caries, and
partial preparation of deep or complex restorations.3,7,17,18,20
The adhesive strength of a
composite resin to enamel varies
from 15–30 MPa.4,18 Based on the
fact that composite resins rarely
fail mechanically with acid-conditioned enamel, it is estimated that
the adhesive strength of a repaired
composite resin should be in this
same range.21 However, results
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March/April 2011
in the literature vary from 2–85
MPa.4,8-11,15,16 These results could be
influenced by many factors, such
as the age of the initial layer, the
superficial condition of the initial
layer, contamination of the surface
of the initial layer with saliva, the
chemical treatment before the
repair, the composite resin viscosity, particle load of the composite,
and the duration of water storage
for the repaired specimens.8-14,18
General Dentistry
www.agd.org
This study sought to evaluate
adhesive strength by varying the
conditions of the adhesive surfaces
and to evaluate superficial roughness
based on surface treatment. The
surface roughness was measured at
seven days or six months after the
composite resin repair and after each
superficial treatment. The roughness average (Ra) was evaluated for
each specimen. Through the surface
roughness analysis in Group 1, the
authors conclude that the six-month
specimens demonstrated an increase
in roughness. This increased roughness could be caused by hydrolytic
degradation, which could start in
the organic matrix, exposing the
fill particles that can disrupt the
material body.10,22 Also, material
characteristics and the length of
time stored in deionized water could
influence this process, causing an
increase in surface roughness.
In the present study, the importance of the surface’s mechanical preparation to be repaired
was considered to increase the
micromechanical and/or chemical adhesive surface area of the
repairing material. A medium grit
diamond bur (between 90 μm
and 120 μm) was used because it
promotes an increase in surface
area, has a low cost, and eliminates
the need for other devices, such
as micro air-abrasive devices. The
use of diamond burs also exposes
fresh composite resin that has not
yet been contaminated by the oral
environment.3,8,23 Many studies
have shown that surface roughness,
caused by surface abrasion, was
more important than chemical
treatment in affecting the adhesive
strength of repaired composites.24,25
Enamel etching with 37% phosphoric acid increased the average
rugosity of the seven-day specimens
and decreased it for the six-month
specimens, although this difference
was not statistically significant. The
acid used in this study is a low-cost
material that is widely recognized by
clinicians and easy to use. It also can
remove superficial debris and ionizate the substrate surface, increasing the surface free energy, which
creates a surface more receptive to
the next material to be used.24
No statistically significant differences in superficial rugosity were
found in the control group, regardless of whether the silane agent was
used prior to application of the
unfilled adhesive agent.
The cohesive resistance in the
control group, where there was no
repair, was the parameter of maximum flexural resistance of the used
material and served as a benchmark
to compare the adhesive strength of
the repaired groups.
The lowest adhesive strength
values were found in Group 2; this
was more evident in the six-month
specimens. This could be caused
by the low wettability of composite
resins combined with their high viscosity, which means that a low-viscosity, unfilled resin is necessary to
penetrate the microcracks of the old
composite resin, thereby increasing
micro-mechanical retention.4,11,17
The wettability is controlled by the
difference of superficial free energy
between the substrate and the adhesive resin and by its viscosity.4 The
phosphoric acid allows a modest
increase in the flexural strength, but
this was not statistically significant.
The best flexural resistance results
were indicated when an unfilled
adhesive resinous agent with high
superficial wettability ability was
used. Previous studies have shown
some advantages of adhesive agents
in composite resin repairs, such as
increasing mechanical retention,
which is important in the repair
resistance.4,9,10,18 The application
of unfilled adhesive between the
increments is essential to obtain an
adequate adhesive resistance.8,14,15
One of the objectives of the use
of silane in composite resin repairs
is to obtain covalent links between
the monomer in the adhesive agent
and the glass particles that lost the
silane covering after mechanical
treatment.26,27 Denehy et al believe
that this procedure improves
hydrolitic stability and mechanical
properties in the repair; however,
its use in the present study did not
affect adhesive resistance, indicating that it is unnecessary.28
Conclusion
Based on the results of this in vitro
study, the authors conclude that
aging unrepaired composite resin in
deionized water for six months did
not decrease its flexural strength.
There was a statistically significant
decrease in flexural strength of
repaired composite resin when only
mechanical treatment was used
prior to the repair. Further, the use
of an unfilled resin agent prior to
the repair is required to increase the
adhesive strength. Finally, the use of
a silane agent prior to the use of the
unfilled resin agent is unnecessary,
since it does not increase the adhesive strength of the repair.
Disclaimer
The authors have no relationship
with any of the manufacturers mentioned in this article.
Author information
Dr. Dias is a postgraduate student,
Department of Operative Dentistry,
School of Dentistry, Rio de Janeiro
State University, RJ, Brazil, where
Drs. Mussel and Sampaio-Filho are
associate professors. Dr. Barceleiro is
head teacher, Department of Operative Dentistry, School of Dentistry,
Nova Friburgo, Fluminense Federal
University, Niteroi, RJ, Brazil.
www.agd.org
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1. Al-Negrish AR. Composite resin restorations: A
cross-sectional survey of placement and replacement in Jordan. Internat Dent J 2002;
52(6):461-468.
2. Gordan VV, Garvan CW, Blaser PK, Mondragon
E, Mjor IA. A long-term evaluation of alternative
treatments to replacement of resin-based composite restorations: Results of a seven-year
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3. Gregory WA, Pounder B, Bakus E. Bond
strengths of chemically dissimilar repaired composite resins. J Prosth Dent 1990;64(6):664668.
4. Puckett AD, Holder R, O’Hara JW. Strength of
posterior composite repairs using different composite/bonding agent combinations. Oper Dent
1991;16(4):136-140.
5. Opdam NJ. Repair and revision 2. Repair or replacement of composite. Ned Tijdschr Tandheelkd 2001;108(3):90-93.
6. Swift EJ Jr, Cloe BC, Boyer DB. Effect of a silane
coupling agent on composite repair strengths.
Am J Dent 1994;7(4):200-202.
7. Christensen GJ. When and how to repair a failing restoration. J Am Dent Assoc 2007;138(12):
1605-1607.
8. Boyer DB, Chan KC, Reinhardt JW. Build-up and
repair of light-cured composites: Bond strength.
J Dent Res 1984;63(10):1241-1244.
9. Rinastiti M, Ozcan M, Siswomihardjo W, Busscher HJ. Immediate repair bond strengths of
microhybrid, nanohybrid and nanofilled composites after different surface treatments. J Dent
2010;38(1):29-38.
10. Fawzy AS, El-Askary FS, Amer MA. Effect of surface treatments of the tensile bond strength of
repaired water-aged anterior restorative microfine hybrid resin composite. J Dent 2008;36(12):
969-976.
11. Chiba K, Hosoda H, Fusayama T. The addition of
an adhesive composite resin to the same material: Bond strength and clinical techniques. J
Prosth Dent 1989;61(6):669-675.
12. Kao EC, Pryor HG, Johnston WM. Strength of
composites repaired by laminating with dissimilar composites. J Prosth Dent 1988;60(3):328333.
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Manufacturers
Dentsply Caulk, Milford, DE
800.532.2855, www.caulk.com
Dentsply International, York, PA
800.877.0020, www.dentsply.com
EMIC Ltd., Sao Jose dos Pinhais, PR, Brazil
41.3283.1143, www.emic.com.br
Gnatus, Ribeirao Preto, SP, Brazil
55.16.2102.5000, www.gnatus.com.br
KaVo America Corporation, Lake Zurich, IL
800.323.8029, www.kavo.com
KG Sorensen, Barueri, SP, Brazil
55.11.4197.1700, www.kgsorensen.com.br
Mitutoyo America, Aurora, IL
888.648.8869, www.mitutoyo.com
COMMENT
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