Orthodontic extrusion for implant site

development revisited: A new classification

determined by anatomy and clinical outcomes
Mark N. Hochman, DDS,1 Stephen J. Chu, DMD, MSD, CDT,2 and
Dennis P. Tarnow, DDS3

A contemporary approach to achieving optimal implant esthetic-restorative

outcomes requires the knowledge to properly diagnose, coordinate, and
execute complex interdisciplinary care. Implant site development utilizing
orthodontic extrusion requires an understanding of many important concepts
and principles of both disciplines of orthodontics and periodontics. This article
reviews basic concepts of orthodontic extrusion and emphasizes a new
diagnostic periodontal classification scheme of the pre-treatment anatomy
that anticipates osseous and soft tissue responses to orthodontic extrusion.
Type 1 classification, the attached gingiva is connected to both bone and root
surface, and during orthodontic extrusion an increase in the width of attached
gingiva will occur. Type 2 classification, the attached gingiva and MGJ is
connected to the root surface, and during orthodontic extrusion the gingival
tissue moves coronally with the tooth, but an increase in the width of attached
gingiva does not occur. Type 3 classification; a periodontal pocket is present
and during orthodontic extrusion the free gingival margin does not move
coronally until there is a complete elimination of the periodontal pocket. In
addition, the article provides a greater understanding of the orthodontic
biomechanical principles and techniques that should be selected based on
anatomical considerations for each patient. Mastering the diagnostic and
technical aspects of orthodontic extrusion is an invaluable addition to the
interdisciplinary practice as it can provide an effective means to treat soft
tissue and osseous vertical deficiencies of the periodontium. Orthodontic
extrusion may therefore represent a unique treatment alternative to some
of the most challenging esthetic situations. (Semin Orthod 2014; 20:208–227.)
& 2014 Elsevier Inc. All rights reserved.

Introduction the esthetic zone. One testament is the myriad of

treatment alternatives that have been developed
here is, arguably, nothing more rewarding
T for today's dentists than to gain confidence
in their ability to achieve predictable outcomes in
to address a wide scope of dental concerns. When
developmental or pathologic processes afflict
patients causing them to seek esthetic-restorative
solutions in the anterior region of the oral cavity,
1
Former Associate Clinical Professor, NYU College of Dentistry; orthodontic extrusion has emerged as an inno-
Private Practice of Periodontics and Orthodontics, New York, New vative and unique alternative for achieving
York, USA; 2Clinical Associate Professor, Department of Period-
ontology and Implant Dentistry, Department of Prosthodontics, NYU
optimal results.1–5
College of Dentistry, New York, New York, USA; 3Clinical Professor, Orthodontic extrusion, also known as forced
Director of Implant Education, Columbia University College of Dental eruption, was first identified as a treatment
Medicine, New York, New York, USA. option to change the relative position of teeth
Address correspondence to Mark Hochman, DDS, 150 East within the alveolar housing through active ver-
58th Street, Suite 3200, New York, NY 10155, USA. E-mail:
PerioOrtho@aol.com
tical eruption of teeth in an occlusal direction.6
& 2014 Elsevier Inc. All rights reserved.
The application of a controlled orthodontic
1073-8746/12/1801-$30.00/0 force to teeth resulted in a mechanically
http://dx.doi.org/10.1053/j.sodo.2014.06.007 mediated eruption to occur, hence the term

208 Seminars in Orthodontics, Vol 20, No 3 (September), 2014: pp 208–227

 Orthodontic extrusion for implant site development revisited 209

Figure 1. Pre-treatment view on left and orthodontic extrusion post-treatment view on right displaying
reformation of the interdental papilla. Improved gingival contour and esthetics.

“forced eruption.”7 This type of tooth movement extrusion to resolve the restorative challenge of
was initially used to change the bony topography insufficient clinical crown length for proper
around teeth by taking advantage of bone restorative ferrule, which otherwise required
responses to orthodontic forces. In 1972, either periodontal surgical crown lengthening or
Brown8 described such a technique as a exodontia as the definitive form of treatment.
corrective procedure toward elimination of Ingber pointed out the resultant unfavorable
infrabony defects resulting from periodontal crown-to-root ratio from surgical removal of
disease. He suggested that altering the osseous supporting bone when utilizing periodontal
configuration through controlled tooth crown-lengthening procedures. In contrast, he
movement could improve and even eliminate highlighted the beneficial effect orthodontic
intra-osseous vertical defects. The novel idea of extrusion has on the crown-to-root ratio and the
using a discipline outside of periodontics to treat overlying soft tissues (i.e., increase of the width of
bone loss, i.e., orthodontics, can be considered attached gingiva). Therefore, Ingber is credited
the catalyst that led to interdisciplinary dental with advancing the concept of interdisciplinary
treatment used widely today to address many treatment through clinical case reports and the
challenging dental problems. detailed descriptions of using this type of
In 1974, Ingber9,10 described orthodontic orthodontics in the treatment of various restor-
extrusion as an effective means of treating teeth ative challenges.
deemed non-restorable because of clinical crown More recently, Salama and coworkers were the
fracture and/or subgingival dental caries. He first to publish a series of articles using ortho-
further described the use of orthodontic dontic extrusion to augment bone and soft tissue

Figure 2. Pre-treatment view on left and orthodontic extrusion post-treatment view on right displaying the
increase in the zone of attached gingival tissue.
210 Hochman et al

Figure 3. Type 1 classification. In this anatomical situation, the attached gingiva is firmly connected to both bone
and root surface, and the mucogingival junction is located on the bone. During orthodontic extrusion, an increase
in the width of attached gingiva will occur.

of the recipient dental implant site.11–13 A clas- This article focuses on a contemporary
sification scheme related to findings and treat- understanding of orthodontic extrusion with an
ment was developed by these authors presenting emphasis on discussing how the adaptive capacity
diagnostic guidelines and the therapeutic bene- of the periodontal attachment leads to improved
fits of using orthodontic extrusion to enhance conditions both esthetically and biologically.
sites receiving implants. These authors stated the Differences in biomechanical principles that
notion that a “hopeless tooth is not a useless separate orthodontic extrusion from other
tooth,” in which they advocated using perio- orthodontic movements are also discussed.
dontally compromised teeth to dramatically
improve the esthetic-restorative implant out-
come. Salama and coworkers added to the work Principles of orthodontic extrusion
of Ingber and Brown by using orthodontic When compared to periodontal regeneration
extrusion in another clinical situation, as a pre- techniques, orthodontic extrusion has the
surgical periodontal augmentation technique potential to be an effective alternative for hard
prior to implant placement. and/or soft tissue augmentation.14–17 The dental

Figure 4. Type 1 classification. In this anatomical situation, the attached gingiva is firmly connected to both bone
and root surface, and the mucogingival junction is located on the bone. During orthodontic extrusion, an increase
in the width of attached gingiva will occur.
 Orthodontic extrusion for implant site development revisited 211

Figure 5. Type 2 classification. In this anatomical situation, the attached gingiva and associated MGJ is firmly
connected to the root surface and not found on bone. During orthodontic extrusion, the gingival tissue moves
coronally with the tooth, but an increase in the width of attached gingiva does not occur.

anatomy of the intact periodontium consists of approximate to the root.19–21 Therefore, the
the tooth cementum, bone, gingiva, and the periodontium can be predictably manipulated by
periodontal ligament fibers. Orthodontic tooth using controlled tooth movement to provide the
movement affects these anatomical structures by desired and only non-surgical technique of
translating forces to produce a predictable bio- producing new bone.
logic response. The mechanical eruption of the Orthodontic extrusion also has an additional
tooth involves applying a direct force to the tooth benefit that affects the overlying gingival soft tis-
in a specific direction. This force creates a ten- sues.10,11,14 There can be an increase in the spatial
sion on the periodontal ligament fibers, making volume, particularly the height, of the gingival soft
them stretch and elongate. This stretching of the tissue as a result of this type of movement.4 This has
periodontal fibers on the surface of the bone can important clinical implications as orthodontic
mediate cellular changes that lead to the desired extrusion compared to surgical techniques is
formation of new bone.18 When orthodontic reported as the most predictable means of correc-
eruption is implemented, new bone formation is ting the loss of the interdental papilla4,5,16,17,22,23
produced at the crestal aspect of the alveolar (Fig. 1). Orthodontic extrusion, therefore, provides
bone and along the surface of the bone a predictable solution in situations where there has

Figure 6. Type 2 classification. In this anatomical situation, the attached gingiva and associated MGJ is firmly
connected to the root surface and not found on bone. During orthodontic extrusion, the gingival tissue moves
coronally with the tooth, but an increase in the width of attached gingiva does not occur.
212 Hochman et al

Figure 7. Type 1 and Type 2 classifications. The image on the left is Type 1 and the image on the right is Type 2.
The relative position of the MGJ is identified in blue and the position of the crest of the bone is marked in green.
To anticipate the outcome from orthodontic extrusion, these landmarks need to be identified.

been a loss of the height of the gingival soft tissues, supracrestal fibers. As the tooth is moved to its
which can be particularly problematic in the new location, these fibers become the
esthetic zone24,25 (Fig. 2). supporting structure for the reformation of

Periodontal gingival response to

orthodontic extrusion
The response of the periodontium to ortho-
dontic forces is evident both on a macro- and
micro-level. This discussion is in context with the
understanding that the periodontal attachment
and the supracrestal fibers of the gingival com-
plex both play a role in the soft tissue anatomy.
As these structures collectively form the attach-
ment coronal to the crest of the bone, they play a
critical role in changing the hard and soft tissue
topography during tooth movement.18,19 The
periodontal ligament and the supracrestal gin-
gival fibers connect the tooth to the bone. As the
orthodontic force moves the tooth coronally,
these fibers stretch; this in turn produces tension
in the bone on a cellular level, which causes
bone deposition.26 The supracrestal fibers play
a central role in the soft tissue morphology Figure 8. Type 3 classification. In this anatomical
before and after tooth movement. The papilla situation, a periodontal pocket is present and is
and surrounding gingival tissue is mainly confirmed with a loss of attachment. During ortho-
composed of connective tissue with highly dontic extrusion, the free gingival margin may not
move coronally until there is a complete elimination of
organized fiber groups. These are the cir- the periodontal pocket and the eversion of the apical
cumferential, transseptal, dento-gingival, and attachment of the periodontal pocket produced
dentoperiosteal, collectively known as the during extrusive tooth movement.
 Orthodontic extrusion for implant site development revisited 213

Figure 9. Type 3 classification. In this anatomical situation, a periodontal pocket is present and is confirmed with a
loss of attachment. During orthodontic extrusion, the free gingival margin may not move coronally until there is a
complete elimination of the periodontal pocket and the eversion of the apical attachment of the periodontal
pocket produced during extrusive tooth movement.

the interdental papilla and mid-facial gingiva in response is based upon an understanding of the
its new location. The concept of orthodontic following three parameters: (1) measuring the
extrusion leading to papilla regeneration is sulcus or pocket depth prior to tooth movement,
therefore a misnomer; it is more accurately (2) determining the position of the mucogingival
described as the reformation of the papilla in a junction (MGJ) relative to the crest of the bone,
new location. and (3) transgingival probing under local anes-
Gingival health and the absence of gingival thesia or “bone sounding” to determine
inflammation and/or disease are critical to the location of the crest of the bone and whether
ensuring successful biologic and esthetic out- there is attached gingiva connected to the
comes.11 Tooth movement in the presence of root surface and/or the periosteum of the
gingival inflammation has long been understood bone.4,16,33,34
as a contraindication to treatment for multiple
reasons. The undesirable outcomes of
accelerated bone loss, increased mobility, and
unpredictable soft tissue responses have been
reported when teeth are moved in the presence
of inflammation.26–28 Gingival inflammation
produces a cascade of cellular responses that
disrupts the highly organized arrangement of
the periodontium. These pathologic changes
impact the supracrestal fibers as well and can
result in changes to the osseous and soft tissue
response producing unpredictable outcomes
that can be undesirable during orthodontic
tooth movement.29,30 Therefore, every effort
must be made to create a healthy tissue envi-
ronment prior to initiating orthodontic move-
ment of teeth.31,32

Classification of soft tissue response to

orthodontic extrusion Figure 10. Bodily tooth movement in which under-
mining bone resorption occurs all along the entire surface
The authors have identified three distinct out- on the pressure side of the tooth. This is contrasted by
comes of the soft tissue in response to ortho- bone apposition along the entire tension surface of the
dontic extrusion. Anticipating the gingival tooth when moved in a horizontal direction.
214 Hochman et al

Type 1: Increase of width of attached gingiva and

overall soft tissue width.
This outcome results when MGJ is attached to the
underlying surface of the bone and the attached
gingiva is connected to both bone and root
surface (Fig. 3). As the tooth is orthodontically
moved in a coronal direction, one can expect an
increase in the width of attached gingiva. In this
anatomical situation, the attached gingiva is
firmly connected to the bone thus preventing
MGJ from migrating coronally with the tooth.
Therefore, the only available biologic response of
the attached gingiva is to expand vertically
resulting in an increased width of this zone
(Fig. 4).
Figure 11. An extrusive force applied in a coronal
direction upon the facial surface of a maxillary
anterior tooth. It will produce a clockwise moment Type 2: Increase of overall soft tissue width with
that will cause the apex of the tooth to move in a facial
direction.
no effect on the width of attached gingiva.
This outcome results when MGJ and the attached
Proper evaluation of these parameters gingiva is connected to the root surface and not
prior to tooth movement increases the predict- the surface of the bone (Fig. 5). Clinical
ability of the resulting soft tissue architec- scenarios where MGJ is located on the root
ture after orthodontic extrusion and helps surface include developmental factors such as a
informing the patient regarding outcomes and/ bony dehiscence defect or a Type 2 altered
or the need for additional procedures after tooth passive eruption or pathological situations such
movement. as a history of bone loss. As a result, when the
This classification describes three types of soft tooth moves coronally, it carries along with it the
tissue responses to orthodontic extrusion, which point of attachment of MGJ and the attached
are as follows: gingiva (Fig. 6).

Figure 12. The series illustrates an anterior maxillary tooth with a normal incisal inclination. When a coronal force
is applied to the facial surface of the tooth during orthodontic extrusion, it will cause the apex of the tooth to move
in a facial direction if a counter-torqueing moment is not provided. This will lead to an undesirable outcome of
either a fenestration or dehiscence of facial plate of bone as a consequence of this type of tooth movement.
 Orthodontic extrusion for implant site development revisited 215

Figure 13. A clinical example of orthodontic extrusion using a provisional restoration to apply a force through the
long axis of a tooth. This technique minimizes a forward clockwise movement from being produced during vertical
extrusion of these teeth thus preserving the facial plate of bone during this type of tooth movement. Pre-treatment
view of teeth number 8 & 9 requiring orthodontic extrusion of non-restorable fractured teeth.

Figure 14. A clinical example of orthodontic extrusion using a provisional restoration to apply a force through the
long axis of a tooth. This technique minimizes a forward clockwise movement from being produced during vertical
extrusion of these teeth thus preserving the facial plate of bone during this type of tooth movement. Use of intra-
coronal elastic thread applied through a provisional restoration. View of provisional restoration showing the access
holes in which elastic threads will pace to engage teeth number 8 & 9.

Figure 15. A clinical example of orthodontic extrusion using a provisional restoration to apply a force through the
long axis of a tooth. This technique minimizes a forward clockwise movement from being produced during vertical
extrusion of these teeth thus preserving the facial plate of bone during this type of tooth movement. Use of intra-
coronal elastic thread applied through a provisional restoration.
216 Hochman et al

Figure 16. A clinical example of orthodontic extrusion using a provisional restoration to apply a force through the
long axis of a tooth. This technique minimizes a forward clockwise movement from being produced during vertical
extrusion of these teeth thus preserving the facial plate of bone during this type of tooth movement. Pre-treatment
view on the left and the post-treatment orthodontic extrusion on the right. Note an increase in the zone of attached
gingiva as this patient exhibits a Type 1 classification.

It is important to diagnose which anatomical described above. A series of studies were con-
situation is present, Type 1 or Type 2, prior to ducted in which supracrestal fiberotomies were
tooth movement so that one may anticipate the performed simultaneously with forced eruption
resulting tissue architecture (Fig. 7). Additional to determine if the osseous and soft tissue
soft tissue procedures, such as soft tissue grafting, responses could be altered.20,35 The primary
may be needed in Type 2 situations to increase objective of these studies was to eliminate the
the zone of keratinized tissue after tooth need for a subsequent surgical crown length-
movement is completed. ening in patients with insufficient clinical crown
length of fractured teeth. The studies demon-
strated that intra-sulcular incisions made to the
Type 3: Width of attached gingiva and overall
bone crest, i.e., fiberotomies, performed simul-
width of soft tissue are unchanged.
taneously with orthodontic extrusion eliminated
After orthodontic extrusion is completed, the the need for a subsequent surgical crown-
position of the free gingival margin has not lengthening procedure on these teeth. These
moved. This outcome is found in cases where findings confirmed that the surgical dissection of
there has been an advanced loss of periodontal the supracrestal fibers prevented coronal move-
attachment on the surface of the root and there is ment of bone during orthodontic extrusion.
a periodontal pocket present (Fig. 8). In this Additionally, it was demonstrated that there was a
situation, neither the MGJ nor the attached reduction in the increase of the gingival width
gingiva is connected to the root surface. when compared to teeth in which fiberotomies
Therefore, before there is any gain in gingival were not performed. These studies concluded
width, the periodontal pocket must first be fully that fiberotomies alter the coronal migration of
eliminated through tooth movement. This both the osseous and gingival soft tissues through
extrusive movement results in a complete the disruption of the supracrestal fibers.20,35 It is
eversion of the base of the periodontal pocket therefore critical to identify the soft tissue clas-
prior to observing any changes in the gingival sification type and the intended use of ortho-
width. If the depth of the pocket is greater than dontic extrusion when considering fiberotomies.
the distance the tooth is extruded, there will be If crown lengthening is the goal of the ortho-
no increase of soft tissue width (Fig. 9). dontic extrusion, fiberotomies may be indicated
With the aforementioned understanding of as an adjunctive procedure as long as an increase
how the pre-existing anatomy influences the soft of soft tissue width is not required. However, if
tissue response to orthodontic extrusion, it implant site development with tooth removal is
should be mentioned that surgical and/or the treatment endpoint, one should first deter-
inflammatory insults would change the outcomes mine the soft tissue classification and consider
 Orthodontic extrusion for implant site development revisited 217

Figure 17. A clinical example of orthodontic extrusion using a provisional restoration to apply a force through the
long axis of a tooth. This technique minimizes a forward clockwise movement from being produced during vertical
extrusion of these teeth thus preserving the facial plate of bone during this type of tooth movement. Flapless
extraction of teeth numbers 8 and 9 with immediate implant placement.

whether fiberotomies will interfere with the management in the facial–lingual, inciso-gin-
desired soft tissue outcome. Note, in almost all gival, and mesial–distal directions.
situations of implant, site development combined A review of literature on the subject of
with tooth removal fiberotomies is contra- orthodontic extrusion reveals that it has been
indicated, as they will impede the maximum referred to as a simple or uncomplicated
amount of bone that can be formed. movement.8,9,11 The authors have come to
understand that, although applying such a force
may be “simple,” the effects of such a force are
Principles of orthodontic extrusion found to be far more complicated than one
might expect. A more thorough analysis of the
Biomechanics
application of force, center-of-resistance, and
Orthodontic tooth movement is traditionally resultant movement demonstrated that ortho-
understood as a discipline that is concerned with dontic extrusion is complex requiring an
space management in the three planes of space: understanding of multiple variables in order to
sagittal, coronal, and transverse. The primary achieve predictable results.
movements of teeth are related to tooth move- A simple movement, in orthodontic terms,
ments that facilitate the correction of bodily refers to a movement that results from the
movement, rotations, tipping, torque, and space application of a vector of force in a single

Figure 18. A clinical example of orthodontic extrusion using a provisional restoration to apply a force through the
long axis of a tooth. This technique minimizes a forward clockwise movement from being produced during vertical
extrusion of these teeth thus preserving the facial plate of bone during this type of tooth movement. Flapless
extraction of teeth numbers 8 and 9 with immediate implant placement.
218 Hochman et al

direction, producing a movement in a single in fixed appliances were never intended for pure
direction. An example is horizontal bodily vertical extrusive movements. These brackets
movement of a tooth (Fig. 10). More complex were designed to optimize movement of teeth
movements are produced when a force is applied into an idealized position within the alveolar
at a specified distance from the center-of- bone. In contrast, orthodontic extrusion often
resistance resulting in a rotational movement has the intended objective to move teeth to
known as a “moment” (Fig. 11). This specific extreme positions, often to the point of extrac-
movement has even more complexity particularly tion. In essence, effective tooth movement for
when it occurs in a constrained body, such as a implant site development involves moving teeth
tooth held in the alveolar bone. to the limits of the alveolar bone. This outcome is
One must also keep in mind that the current hampered by current bracket design technology,
generation of orthodontic bracket designs used as will be addressed later.

Figure 19. A clinical example of orthodontic extrusion using a provisional restoration to apply a force through the
long axis of a tooth. This technique minimizes a forward clockwise movement from being produced during vertical
extrusion of these teeth thus preserving the facial plate of bone during this type of tooth movement. (A)
Immediate post-operative view on the day of removal of teeth numbers 8 and 9 on the left, and 9-month post-
surgical view with final restorations of the maxillary anterior teeth on the right. Note the general health of the
gingival tissues, retention of the interdental papilla, and an improved clinical crown length (tooth proportion) of
teeth numbers 8 and 9 resulting in a favorable esthetic-restorative implant outcome. (B) This series illustrates an
anterior maxillary tooth during orthodontic extrusion into a provisional restoration. When a vector of force is
applied directly through the center-of-resistance into the provisional restoration in a coronal direction, the apex of
the tooth will move in that same direction. This will eliminate the undesirable forward clockwise movement of the
apex of the tooth during extrusion.
 Orthodontic extrusion for implant site development revisited 219

Figure 20. Clinical exam shows a patient with 3–4 mm of gingival recession and 5 mm of probing depths on teeth
numbers 8 and 9. The patient's chief complaint included loss of interdental papilla, food entrapment in space and
excessive mobility of these teeth.

Anatomic considerations in the esthetic apex of a tooth when moved in a coronal

zone direction. The forward clockwise moment will
cause the apex of the tooth to be driven in a facial
The biomechanical principles of orthodontic direction with possible perforation through the
extrusion are also affected by the anatomy of the apical portion of the facial alveolar bone plate. It
pre-maxilla. Therefore, implant site develop- is interesting to note that the dental literature has
ment and papilla reformation in the anterior recently documented that the facial plate of bone
maxillary region present challenges not found in thickness on anterior teeth is 0.5–1.0 mm on
the posterior region since these teeth have an average (⫾0.3 mm) even when 10 mm apical
upright and vertical axial inclination. Maxillary from the CEJ.38–40 Therefore the more proclined
anterior teeth have an inherent proclined axial an anterior tooth is, the greater the risk of per-
inclination. This angulation can be measured foration and the greater the need to counteract
using standard cephalometric analysis such as the the forward clockwise moment at the apex
Steiner analysis. The analysis uses the interincisal (Fig. 12). These authors contend that the axial
angle and maxillary central incisor to NA angle to inclination of anterior teeth requires a more
determine if the inclination of the maxillary careful evaluation of this facial–palatal perspec-
incisor is normal, retroclined, or proclined rel- tive prior to orthodontic extrusion movement. In
ative to the skeletal base.36,37 The anterior tooth addition, careful consideration with respect to
with a proclined axial inclination will produce a appliance design is warranted to prevent apical
forward clockwise (left–right) moment upon the bone perforation or facial dehiscence.

Figure 21. Radiographic evaluation reveals 40–50% horizontal bone loss on teeth numbers 8 and 9 in periapical
radiographs. In addition, CBCT suggests a lack of labial cortical plate of bone on teeth numbers 8 and 9.
220 Hochman et al

Figure 22. Orthodontic extrusion of teeth numbers 8 and 9 with a base archwire and a secondary archwire (0.016
NiTi) to produce vertical extrusion. Active tooth movement is performed over a 12-month period. Extensive
occlusal equilibration was required during orthodontic extrusion. Note the new position of the gingival margin
and improved position of the interdental papilla.

Previous publications have documented a high Orthodontic edgewise brackets are designed
incidence of fenestrations as a result of ortho- with an angulation of tip and torque incorpo-
dontic extrusion. This undesirable outcome was rated into every bracket specific for each indi-
most likely the result of a lack of control of the vidual tooth of the maxillary and mandibular
forward clockwise moment that was produced jaws. Andrews popularized this treatment
during orthodontic extrusion.9,10,16,41 approach.42 This is accomplished by the bracket's
Torque control can be managed in three slot design and angulation to the bracket base.
different ways: (1) negative torque brackets in Negative high-torque brackets used in the pre-
combination with rectangular archwires, (2) maxillary region will provide increased lingual
vertical loops with rectangular archwires, and (3) root torque to position the apex of the tooth root
“bracket-less” technique by using a tooth-borne toward the palate. It is noteworthy that a rec-
fixed provisional restoration to anchor the tangular archwire needs to be engaged in the
extrusive force. Each of these techniques will be bracket slot when an edgewise bracket is used to
subsequently discussed. control torque as this can maximize the force

Figure 23. Orthodontic extrusion of teeth numbers 8 and 9 with a base archwire and a secondary archwire (0.016
NiTi) to produce vertical extrusion. Active tooth movement is performed over a 12-month period. An additional 6
months of stabilization was provided after active tooth movement to allow bone maturation prior to tooth removal
and the placement of dental implants. Left image shows the repositioning of brackets on the root surface of teeth 8
& 9 during treatment which was necessary. Right image is of the final position of teeth after orthodontic extrusion.
Note the reformation of the interdental papilla on teeth 8 & 9 and an increase in the width of attached gingiva at
completion of tooth movement.
 Orthodontic extrusion for implant site development revisited 221

Figure 24. Orthodontic extrusion of teeth numbers 8 and 9. Pre-treatment radiograph (far left) displays 40% to 50%
horizontal bone loss prior to movement. Sequential radiographs taken at six, nine and twelve months demonstrates
the reformation and improved vertical height of the alveolar crest of bone that was achieved during treatment.

exerted to the apex of the tooth. Utilizing round individually constructed archwires that possess
archwires in an edgewise bracket cannot effec- wire-specific configurations. For instance, the use
tively produce proper counterbalancing move- of vertical “T” loops can be made using a rec-
ments. Therefore, it is equally important to use tangular Beta-Titanium wire to produce a vertical
the proper size and shape of rectangular arch- extrusive force. This type of wire construction
wires when relying upon orthodontic coupling allows greater control in the vertical direction
forces to control the clockwise moment during while simultaneously enabling effective root
orthodontic extrusion. The authors have used torque control that is produced by a rectangular
this approach with success. archwire. The negative implications of using
A second effective means of controlling root vertical “T” loops and the like can be the addi-
torque during orthodontic extrusion is using tional time it takes to construct these appliances.

Figure 25. Cross-sectional CBCT radiograhic views of teeth numbers 8 (left image) and 9 (right image) at the
completion of tooth movement. Controlled facial extrusion in combination with vertical extrusion produced
increased bone dimensions in both the vertical as well as the buccal–lingual dimensions of the alveolar ridge. This
non-surgical bone augmentation using orthodontic tooth movement was sufficient to allow the placement of
dental implants at site numbers 8 and 9.
222 Hochman et al

Figure 26. A flapless extraction of teeth numbers 8 and 9 was performed concurrently with immediate implant
placement at site numbers 8 and 9. Note soft tissue preservation of the interdental papilla and the surrounding
normal gingival architecture.

The comfort of the patient is also a factor when along the long axis of the tooth. A tooth-borne
using archwires with loops and elaborate designs; provisional restoration offers this unique
however, when properly designed, they can be requirement. Full-coverage acrylic provisional
well tolerated. restorations used to “house” the erupting tooth
A third means for providing effective root not only provide long-axis vectoring forces but
torque control during extrusion is by applying a also a more esthetic option during movement
force from an alternative point on the tooth. when compared to bracket placement on the
A biomechanical appliance design in which the labial surface of an anterior tooth since there are
force vector moves through the center-of- no buccal brackets on these teeth (Figs. 13–19).
resistance of the tooth minimizes and can There are many creative options using a
often eliminate the undesirable forward clock- provisional restoration as an orthodontic appli-
wise moment that is seen when a facial bracket is ance. The following features need to be present
placed on the tooth. The key factor in the design to accomplish these goals. The provisional
of such an appliance is to align the vector of force restoration needs to be supported by the

Figure 27. Occlusal clinical view of implant position at site number 8 and 9 immediate post implant placement.
Radiograpic view of implants immediate post implant placement.
 Orthodontic extrusion for implant site development revisited 223

Figure 28. The images from left to right show a series of steps required in the fabrication of a properly contoured
immediate implant provisional crowns at the time of implant placement. The development of a proper emergence
profile in the subgingival area tissues is emphasized with the bold arrows on the labial surface of these restorations.

adjacent teeth and/or implants. The tooth to be The biomechanical advantage to employing a
extruded requires sufficient reduction of the provisional restoration is shown in the accom-
remaining clinical crown (tooth preparation) so panying diagram (Fig. 19B). Note that when the
that it can be accommodated into the provi- force application can be applied from the center
sional. Modifications to the internal surface of of the crown in a coronal direction, the force
the provisional restoration need to be made so vector can be applied through the center-of-
that the prepared tooth has sufficient internal resistance of the tooth. This biomechanical
clearance during tooth movement. Lastly, a model demonstrates bodily movement through
means of generating adequate force from the pure translation in an occlusal direction.
provisional to the tooth to be moved, typically an Therefore, the use of a provisional restoration
elastic thread (0.025 in.), can be used with a light provides a means to avoid creating the forward
force of less than 80 g. This will provide move- clockwise moment typically found when fixed
ments of 1–2 mm per month. Frequently, pro- facial brackets are used.
phylactic endodontic therapy is performed to Awareness of the aforementioned principles
eliminate the potential for pulp exposure during enables clinicians to understand the subtle but
tooth reduction and to allow preparation critical differences between conventional tooth
through the clinical crown for elastic ligation as movement and orthodontic extrusion. This
previously described. knowledge and the proper application of a

Figure 29. The images from left to right show a series of steps required in the fabrication of a properly contoured
immediate implant provisional crowns at the time of implant placement. The development of a proper emergence
profile in the subgingival area tissues is emphasized.
224 Hochman et al

variety of innovative techniques will yield great however, this did not address the patient's chief
predictability of functional and esthetic results. complaint that included the loss of the
interdental papilla. In addition to the esthetic
concern, the “black triangle” led to difficulty in
Case presentation
speaking and food entrapment. After careful
A 48-year-old male patient with an unremarkable interdisciplinary analysis, a treatment alternative
medical history presented for comprehensive designed to correct this deficiency was proposed
dental treatment. A periodontal diagnosis of to the patient. Orthodontic extrusion leading to
localized moderate to severe periodontitis with extraction of numbers 8 and 9 would be used for
localized horizontal bone loss and moderate to repositioning the interdental papilla and vertical
severe (localized) gingival recession was noted bone growth with the anticipation of placement
on the maxillary central incisors (Fig. 20). The of dental implants at these sites (Figs. 22–24).
patient's chief complaint was “I have a large space CBCT revealed the facial–lingual thickness of
between my front teeth and these teeth feel bone would be insufficient to accommodate the
loose.” Radiographic evaluation revealed 40– appropriate size of implants. To meet this chal-
50% bone loss of teeth numbers 8 and 9 lenge, and with the knowledge of the bio-
(Fig. 21). Clinical exam revealed localized mechanical principles already discussed, an
probing depths of 5 mm with 3–4 mm of innovative approach was proposed to augment
gingival recession on the facial aspect of these the recipient implant site. Owing to the axial
teeth. This patient was diagnosed as a Type I inclination of these teeth and the local anatomy
attachment in which MGJ is attached to the of the pre-maxilla of this patient, the authors
periosteum and the attached gingiva is proposed that applying an “excessive” forward
connected to the root surface. Mobility was clockwise moment to the apex of teeth numbers
scored as Class II according to the Miller scale. 8 and 9 would cause the roots to be labial to the
These teeth had previous endodontic therapy as facial plate of bone. The authors term this
a result of severe root sensitivity. Cone beam technique “controlled facial extrusion” defined
computer tomography (CBCT) suggested a lack as a variant of orthodontic extrusion in which a
of the facial cortical plate of bone on these teeth controlled facial (forward clockwise) moment is
(Fig. 21). Pertinent cephalometric information employed to allow bone apposition along the
included Steiner analysis, an incisal angle of 1251, palatal aspect of the root thereby regaining the
and an interincisal angle of 971. Multiple lost facial–palatal dimension of the alveolar ridge
treatment options were proposed. One (Fig. 25). This deliberate controlled movement
treatment option was closure of the diastema would result in orthodontically facilitated bone
with conventional fixed orthodontic appliances; deposition along the root surface resulting from

Figure 30. Clinical view of the final implant supported restorations at the 1-year follow-up visit on the left. CBCT
demonstrates the presence of a facial cortical plate of bone on the surface of implant numbers 8 and 9 on the right.
Controlled facial orthodontic extrusion in combination with vertical extrusion provided effective implant site
development to the gingival tissues and the underlying supporting bone simultaneously and non-surgically.
Orthodontic extrusion represents a reliable option for the multidisciplinary patient.
 Orthodontic extrusion for implant site development revisited 225

the tension along the entire surface of the palatal and soft tissues. In addition to immediate implant
aspect of these teeth during movement. As descri- placement into the regenerated sites, fabrication
bed previously, the surface tension promotes of properly contoured immediate implant pro-
bone apposition along the entire front of these visional crowns is a critical component to the
teeth as they are moved away from the bone in a preservation of the soft tissue gingival contour
facial–occlusal direction. The reformation of an (Figs. 27–29). The proper restorative contours
adequate thickness of the alveolar ridge using created by the provisional restorations were
orthodontic facial and vertical extrusion is a transitioned to the definitive ceramo-metal
unique method of movement. Additionally, the restorations (Fig. 30).
controlled facial and vertical orthodontic
extrusion technique would result in an incre-
Discussion
ase in the width of attached gingiva and the
reformation of the interdental papilla between The technique of orthodontic extrusion has been
teeth numbers 8 and 9 fulfilling the second utilized for a variety of applications in dentistry
treatment objective of using this technique. It since it was first described over 40 years ago.6,7
bears repeating that this technique is performed The initial use of this technique demonstrated
with the final goal of removing the teeth and that it could be used as a means of eliminating
placing immediate post-extraction socket periodontal infrabony defects. Shortly thereafter,
implants after the completion and stabilization of this same technique was used to orthodontically
orthodontic movement. “erupt” fractured teeth so that a sufficient
The patient had active tooth movement over a amount of clinical tooth structure would be
period of 12 months. Once the adequate available to restore a previously non-restorable
dimension of alveolar bone was confirmed via a tooth. The notion to use orthodontic extrusion
subsequent CBCT, the teeth were held in this to regenerate the interdental papilla has now
position for an additional 4–6 months to allow become routine procedure and is currently
time for bone maturation. Soft tissue reposi- accepted as the most predictable technique in
tioning and the reformation of the lost inter- the reformation of the interdental pap-
dental papilla is noted in Fig. 23. Immediate post- illa.4,5,16,17,22,23 More recently, the use of ortho-
extraction socket implant placement was per- dontic extrusion as an effective tool in implant
formed at the time of the removal of teeth site development has become an area of great
numbers 8 and 9 (Fig. 26). The extractions were interest, as this technique provides patients and
performed with a minimally invasive approach clinicians with many advantages when compared
defined as a “flapless” technique using to surgical techniques.4,11,12–25
periotomes and forceps. The biologic rationale There are several disadvantages of using
for a “flapless” technique relates to preserving the orthodontic extrusion as a therapeutic form of
supracrestal fibers and soft tissues that have been treatment. During vertical tooth movement,
established during tooth movement; additionally, occlusal interferences and contact to the oppos-
the “flapless” approach preserves a critical blood ing arch must be eliminated. This often requires
supply for the newly reformed bone. substantial tooth reduction, which can cause
Delayed implant placement after the extrac- sensitivity and/or pulp exposure, requiring pro-
tion of these teeth is contraindicated. The phylactic endodontic therapy (even if these teeth
authors have observed two undesirable outcomes will eventually be extracted). The additional cost
when delayed implant placement is utilized after and time must be explained to the patient.
tooth removal: (1) the newly formed orthodon- Patients are typically seen every 3–4 weeks during
tically facilitated bone will resorb if direct phys- the active phase of tooth movement. These
ical bone stimulation is not maintained and (2) appointments are used to re-activate the force
the gingival tissues will undergo remodeling after applied to the teeth. If a provisional restoration is
tooth removal, with a loss of height and thickness. to be used as the appliance for tooth movement,
The immediate placement of dental implants time must be allotted to remove the cemented
into the matured alveolar ridge after 4–6 months provisional, re-activate the appliance, and re-
of stabilization provides a favorable environment cement the provisional restoration. These
for long-term preservation of the reformed bone repeated visits require significant chair-time for
226 Hochman et al

each visit to accomplish. The total treatment time with the immediate placement of a properly
require to perform these procedures may be 9–18 contoured non-functionally loaded implant sup-
months, and the duration of treatment is deter- ported temporary restoration. Bone and soft tis-
mined by severity of the tissue deficiency and the sue preservation after tooth movement requires
complexity of the tooth movement required. careful planning, execution, and timing by the
Additional time for a retention phase of treat- multidisciplinary team.
ment must be added to the active treatment time,
and this is typically not needed in other treatment
modalities. One must weigh these disadvantages Conclusion
against the unique advantages that orthodontic
extrusion offers. Orthodontic extrusion is a treatment alternative
This article highlights several important ana- with multiple benefits that are not easily dupli-
tomical considerations and biomechanical prin- cated with other more invasive forms of treat-
ciples affecting orthodontic extrusion, not found ment. Among these are the ability to predictably
in the current literature. A novel technique, regenerate osseous and soft tissues, eliminate
controlled facial extrusion combined with verti- infrabony defects, improve the crown-to-root ratio
cal eruption, was defined and described as a of compromised teeth, convert a “non-restorable”
method to augment the facial–palatal width tooth into a restorable tooth, and the use of a
dimension of bone. The authors have sought to “hopeless tooth” for effective site development for
call attention to the potential of producing implant treatment. The use of orthodontic
unwanted outcomes from poorly controlled extrusion will improve the final esthetic-
forces that occur and are unique to the esthetic restorative implant outcome in some of the
zone. The anatomy of the pre-maxilla, the most esthetically challenging clinical situations.
angulation of anterior teeth, and the thickness of Orthodontic extrusion is often the only modality
the facial alveolar bone are paramount factors to that will achieve the optimal esthetic and func-
take into account when designing the ortho- tional outcome where there is extensive loss of soft
dontic appliance to be used for forced eruption. and hard tissues in the esthetic zone. Mastering
As with all orthodontic interventions, gingival the techniques of orthodontic extrusion is an
health also plays a crucial role in a successful invaluable addition to the interdisciplinary prac-
outcome. A discussion of biomechanical vectors tice because they offer predictable results for
and moments that occur during forced eruption clinicians and patients alike.
addressed how this particular type of tooth
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