Challenges in Regenerative Endodontics: A Case Series
Challenges in Regenerative Endodontics: A Case Series
Challenges in Regenerative Endodontics: A Case Series
Abstract
Introduction: An immature tooth with pulpal necrosis
and apical periodontitis presents a unique challenge to
the endodontist. Endodontic treatment options consist
T he treatment of pulpal necrosis in an immature tooth with an open apex presents
a unique challenge to the dentist. Before 2004, clinicians relied on traditional apex-
ification procedures or the use of apical barriers to treat immature teeth with pulpal
of apexification, apical barriers, or more recently, revas- necrosis. Traditional apexification uses long-term calcium hydroxide dressings to
cularization. The purpose of this case series is to report promote the formation of a calcified barrier that an obturation material can be placed
three cases that used revascularization protocol as against. Apexification has proven to be highly predictable (1, 2) but has the downside of
described by Banchs and Trope. Each case presented multiple appointments over a period of months plus an increased susceptibility to
its own special circumstances and challenges. The cervical fracture (3, 4).
lessons learned from each case provided guidance for The artificial apical barrier technique uses a barrier material that is placed at
more predictable outcomes on subsequent cases. the apex to facilitate obturation procedures by containing the obturation material
Methods: Six immature teeth with apical periodontitis within the canal. The material of choice for this procedure is ProRoot Mineral
(in three patients) were treated via the revascularization Trioxide Aggregate (MTA) (Dentsply Tulsa Dental, Tulsa, OK) (5, 6). The technique
protocol using irrigants, a triple antibiotic paste, and is predictable and successful (7, 8) and reduces the number of treatment appoint-
a coronal seal of mineral trioxide aggregate and ments (9). The disadvantage of both traditional apexification and artificial apical
composite. Results: For follow-up, all six teeth showed barriers is that neither allows for thickening of the root wall or continued develop-
resolution of periapical radiolucencies, whereas three of ment of the root.
six teeth showed continued root development. Two One of the first revascularization research efforts was a case report in which the
teeth displayed a positive response to vitality testing. immature tooth was treated with irrigation and disinfection using two antimicrobial
Conclusions: Results from this case series show that agents (metronidazole and ciprofloxacin) with successful revascularization (10). In
revascularization is a technically challenging but effec- 2004, Banchs and Trope (11) published a case report describing a new treatment
tive treatment modality for the immature tooth with procedure for the management of the open apex called ‘‘revascularization.’’ The
apical periodontitis. Based on this case series, the protocol differs from other apexification techniques in that disinfection of the canal
following recommendations are made to help with is performed with both sodium hypochlorite (NaOCl) and chlorhexidine (CHX) and,
the revascularization technique: (1) clinicians should as Hoshino et al (12) described, using a combination of three antibiotics (ciprofloxa-
consider the use of an anesthetic without a vasocon- cin, metronidazole, and minocycline). At a subsequent appointment, the paste is
strictor when trying to induce bleeding, (2) a collagen removed and bleeding is induced into the canal. The canal is sealed with MTA, and, after
matrix is useful for the controlled placement of MTA the MTA has set, a bonded restoration is placed. Unlike traditional apexification or the
to a desired and optimal level, (3) patients/parents use of apical barriers, revascularization procedures allow for an increase in both root
should be informed about the potential for staining, wall thickness and the length of the root. Additionally, the treatment time can be
especially in anterior teeth when the paste contains min- completed in fewer visits than traditional apexification. Further research has compared
ocycline, and (4) patient/parent compliance with the this method with placement of Ca(OH)2 or formocresol (13). Increased root lengths
necessary multiple appointment treatment plan may were seen in the triple antibiotic and Ca(OH)2 groups, whereas only the triple antibiotic
be significant for case selection. (J Endod 2010;-:1–6) group showed increased root wall thickness. Although successful in some cases, there
are still areas of concern. Some problems we discovered are presented in this case
Key Words series using a revascularization protocol. Each case presented its own special circum-
CollaPlug, mepivacaine, mineral trioxide aggregate, stances and challenges, and the lessons learned from each case helped improve the
regeneration, revascularization treatment of subsequent cases.
Case 1
A healthy 13-year-old male was referred for evaluation and treatment of teeth
From the *Division of Endodontics, University of Minnesota
School of Dentistry, Minneapolis, MN; and †Private Practice,
numbers 8 and 9. The patient reported that he had broken his front teeth subsequent
Eagan, MN. to a fall nearly 6 years prior. A sinus tract was noted on the buccal mucosa above tooth
Address requests for reprints to Dr Walter Bowles, Division number 9. After clinical and radiographic examination (Fig. 1A), the diagnosis was as
of Endodontics, University of Minnesota School of Dentistry, follows: tooth number 8 - pulpal necrosis, asymptomatic apical periodontitis and tooth
8-166 Moos Tower, 515 Delaware St SE, Minneapolis, MN number 9 - pulpal necrosis and chronic apical abscess. Revascularization procedures
55455. E-mail address: bowle001@umn.edu.
0099-2399/$0 - see front matter were recommended for both teeth.
Copyright ª 2009 American Association of Endodontists. After informed consent was obtained, the teeth were anesthetized with 2% lido-
All rights reserved. caine with 1:100,000 epinephrine, isolated with a rubber dam, and accessed. Upon
doi:10.1016/j.joen.2009.10.006 access, hemorrhagic, purulent exudate was found in both teeth. The canals were irri-
gated with 20 mL of 5.25% NaOCl, followed by 20 mL of saline, and then 10 mL of 0.12%
Figure 1. (Case 1) This case highlights the difficulty with induction of bleeding when local anesthetic with vasoconstrictor is used and shows problems with initial
placement of MTA. A 13-year-old male presented with fractured incisal edges on teeth 8 and 9. (A) Radiograph showed incompletely formed apices on teeth 8 and 9,
and periapical lesion approximately 1 1 cm associated with both teeth. (B) Placement of MTA barrier in teeth 8 and 9 after induction of bleeding. The problem
inducing bleeding was overcome by using an anesthetic that did not contain a vasoconstrictor. Barrier placement was farther apical than desired. (C) Completion of
composite restorations. Lesions on both teeth at this time appear to be showing signs of healing. (D) A 1-year follow-up showed increased thickness of the apical
area on tooth number 9; no apparent changes observed on tooth number 8 and continued healing of lesions. Both teeth 8 and 9 lacked a response to vitality testing
at this follow up examination.
CHX. This became the irrigation protocol for all four cases. The saline The patient returned to the clinic 3 weeks later. The patient re-
rinse was used to prevent the interaction between NaOCl and CHX (14). mained asymptomatic, and the sinus tract was no longer present. The
The canals were dried, and a triple antibiotic paste consisting of cipro- teeth were again anesthetized with 2% lidocaine with 1:100,000
floxacin, metronidazole, and minocycline (100 mg of each drug in epinephrine, isolated with a rubber dam, and accessed. The triple anti-
a 0.5-mL total volume) was placed. The compounding of the antibiotic biotic paste was removed using 10 mL of 5.25% NaOCl per tooth, and
paste was standardized for all four cases. The teeth were then the canals were dried. Using an endodontic explorer and hand file, all
temporized. attempts to induce bleeding into the canal space on each tooth were
Figure 2. (Case 2) This case shows how the use of a local anesthetic without a vasoconstrictor and the use of a collagen matrix allowed for more predictable
induction of bleeding and optimal placement of MTA. An 11-year-old male presented to clinic for management of a carious exposure on tooth number 29. The
patient also reported a history of discomfort on tooth number 20. (A) A radiograph showing carious exposure of pulp and a well-demarcated radiolucent lesion on
tooth number 29. (B) A radiograph showing incomplete development of tooth number 20 and a well-demarcated radiolucency. (C and D) Radiographs showing
placement of MTA and completion of composite restoration on tooth 29 (C) and 20 (D). In both teeth, CollaPlug was used as a matrix to aid placement of MTA. (D)
A radiograph showing placement of MTA and completion of composite restoration on tooth 20. In this case, CollaPlug was used as a matrix to aid placement of MTA.
(E and F) A 1-year follow-up radiograph showing healing of the radiolucent lesion and increased thickness of the root wall and length on tooth 29 (E) and 20 (F).
Both teeth had a positive response to vitality testing at this follow-up examination. The formation of an apical barrier is also seen with tooth 20 (F).
decision to use revascularization instead of apexification was made revascularization outcome’’ (19), and the induction of bleeding into
primarily because of the potential for increased root length and thick- the canal may provide stem cells, which can induce dentin formation.
ness of root walls. Because this protocol is very technically demanding, Others show regeneration with or without formation of a blood clot
elements of the technique evolved from case to case. Changes may occur (20), suggesting that additional research is needed in this area. Second,
with this technique as more research is completed. Recent studies have the placement of MTA over a blood clot was technically difficult, and
shown that irrigation with CHX may be detrimental to stem cells (15) condensation resulted in apical displacement of the material, which
and may require a modification of our irrigation method with this looked as though an apical barrier had been placed. This may have
technique. been the cause of the subclinical results for this case. This is also shown
In case 1, several challenges in the management were overcome for the placement of Ca(OH)2, where better results were seen when the
and applied to the next case. First, it took several attempts to induce placement of the Ca(OH)2 was restricted to the coronal half of the tooth
bleeding into the canal space. We found that inducing bleeding was (13). The placement of MTA and a blood clot would likely depend on
easier when an anesthetic solution did not contain a vasoconstrictor. presenting circumstances; the more developed the root, theoretically,
Both animal and human studies have shown that there is a significant the more apical it could be placed. Additionally, depending on where
reduction in pulpal blood flow after infiltration injection of anesthetics you can establish a blood clot may have an influence on the placement
containing epinephrine (16–18). We cannot rule out any effect the of MTA. Ideally, the coronal edge of MTA should be placed 1 to 2 mm
triple antibiotic paste may have had on bleeding reduction, but because apical to the CEJ to allow for more root development versus 3 to 4 mm as
the removal of epinephrine from our anesthetic allowed the induction of described by Banchs and Trope (11). The use of a 1-mm thick glass
bleeding, we recommend this technique. Research has shown that the ionomer material may allow for more cervical placement. Results
‘‘inclusion of a blood clot in the canal space tended to improve the from this case also suggest that a resorbable barrier could be placed
Figure 3. (Case 3) A 6-year-old female presenting to the clinic 6 months after teeth 8 and 9 were avulsed. Management of this case allowed for more predictable
induction of bleeding and optimal placement of MTA using techniques learned from cases 1 through 2 above. This case, however, showed the potential for staining
of tooth structure attributed to the minocycline in the antibiotic paste. (A) A radiograph revealed open apices on teeth 8 and 9 and associated periapical lesions. (B)
Placement of MTA barrier over CollaPlug matrix. (C) A clinical photograph showing blue staining on tooth 8 attributed to the minocycline in the antibiotic paste. (D)
A 9-month follow-up radiograph showing healing of lesions on teeth 8 and 9. Increased root length and root wall thickness noted on tooth 9. Formation of an apical
barrier on tooth 8 was noted. Both teeth 8 and 9 lacked a response to vitality testing at this examination.
to serve as a matrix for MTA. The case series from 2007 described the procedures. In the six teeth included here, resolution of the apical
use of CollaTape (Zimmer Dental) as a matrix for the placement of MTA radiolucencies is seen. Additionally, of these teeth, three showed
(21). The authors reported that wetting of the matrix via blood was continued apical development, two showed possible formation of an
observed through the microscope, and MTA was placed over the matrix. apical barrier, and one showed no apparent change apically. Two of
Follow-up radiographs in the 2007 case series showed continued apical the six teeth had a positive response to vitality testing. It is important
development and resolution of the lesion. Cases 2 and 3 used the to note that the elimination of vasoconstrictor from the local anesthetic
lessons learned from our first case. CollaPlug was chosen in cases 2 and the addition of a collagen matrix allowed for more predictable
and 3 instead of CollaTape because CollaPlug fibers handle more easily induction of bleeding and optimal placement of MTA.
than the tape. The staining noted on tooth number 8 in case 3 can be attributed to
The follow-up times for the cases ranged from 9 months to 1 year. the minocycline in the antibiotic paste, which has been noted from our
The nature of a school of dentistry patient population for Endodontic studies on extracted teeth (unpublished data) and may have been
and Pediatric Dental Clinics makes compliance with appointment inter- caused by residual paste in the pulp chamber or neck of the tooth.
vals, multiple appointments, and follow-ups a significant challenge. Another source of staining may be residual tissue above the MTA or
Because revascularization cases require stringent follow-up, noncom- even the MTA material. The restorative and esthetic management can
pliance of the patient/guardian may be a contraindication for these be challenging. The potential for staining does not occur every time