Page 1 of 14
CASE REPORT
Treatment of a high angle protrusion case
optimized with interdisciplinary
approaches and TSADs
Johnny J.L. Liaw,a,b Jae Hyun Park,c Irene Y.H. Shih,b Stella Y.H. Yang,a,b and Fang Fang Tsaib
Taipei, Taiwan, Mesa, Ariz, and Seoul, South Korea
With the aid of temporary skeletal anchorage devices, a patient with severe skeletal Class II bimaxillary
protrusion combined with a high mandibular plane angle and retruded chin can be treated to an accept- able result without orthognathic surgery. Combined intrusion and retraction force systems on both arches
with 6 miniscrews were used in this case report for maximal retraction and active vertical control to
improve facial profile and chin projection. The infrazygomatic crest and buccal shelf temporary skeletal
anchorage devices helped achieve maximal retraction of both dentitions and lips, significantly reducing
the protrusion. The anterior subapical miniscrews helped to control the overbite and the incisor torque.
Moreover, active vertical control was achieved to reduce the mandibular plane angle and resulted in coun- terclockwise rotation of the mandible and an improved chin projection. A fairly good treatment result was
achieved with adequate communication between the orthodontist, periodontist, and prosthodontist. (Am
J Orthod Dentofacial Orthop Clin Companion 2021;1:245–58)
Bimaxillary protrusion is common in the Asian popu- lation. Four premolar extraction has been the tradi- tional way to reduce the protrusion orthodontically
and improve the facial profile.1,2 Anchorage control is criti- cal for maximal retraction and profile improvement, espe- cially in patients with thick soft tissues, whose soft tissue
response to incisor retraction is generally less than
normal.3,4 The use of temporary skeletal anchorage devi- ces (TSADs) is helpful for more incisor retraction and, con- sequently, for profile improvement.5 A patient with an
extra extraction space of a hopeless maxillary molar cre- ated a dilemma regarding whether to close the space or
not. Closing all the spaces would provide more retraction,
but unilateral space closure of one extra molar space
might result in midline deviation. Maintaining the space
and restoring it with a dental implant would be a more
conservative and safe approach, but there would be less
improvement of the facial profile. This case report
describes a severe bimaxillary protrusion with a retruded
chin, complicated by multiple prostheses and a hopeless
maxillary right first molar, for which we were able to
achieve acceptable treatment results using an interdisci- plinary approach with the help of TSADs.
DIAGNOSIS AND ETIOLOGY
A 24-year-old female patient asked for orthodontic
treatment with the chief complaint of severe protrusion.
Clinical examination showed a convex profile, perioral pro- trusion, and mandibular retrognathism (Figs 1 and 2 ). The
Johnny J.L. LIaw Jae Hyun Park
a
Department of Orthodontics, National Taiwan University Hos- pital, Taipei, Taiwan.
b
Beauty Forever Dental Clinic, Taipei, Taiwan.
c
Postgraduate Orthodontic Program, Arizona School of Den- tistry & Oral Health, A.T. Still University, Mesa, Ariz and Inter- national Scholar, Graduate School of Dentistry, Kyung Hee
University, Seoul, South Korea.
All authors have completed and submitted the ICMJE Form for Dis- closure of Potential Conflicts of Interest, and none were reported.
Address correspondence to: Jae Hyun Park, Postgraduate
Orthodontic Program, Arizona School of Dentistry & Oral
Health, A.T. Still University, 5835 E Still Circle, Mesa, AZ
85206; e-mail, jpark@atsu.edu
December 2021, Vol 1, Issue 4 245
Page 2 of 14
Fig 1. Pretreatment facial and intraoral photographs.
Fig 2. Pretreatment study models.
Liaw et al.
246 AJO-DO CLINICAL COMPANION
Page 3 of 14
patient’s nasolabial angle was obtuse and mentalis strain
was noted at lip closure. Her chin was quite retruded. Ver- tical proportions were within the normal range. Facial
asymmetry was also noticed, with the chin point slightly
deviated to the left. Intraorally, the overjet was 1.5 mm,
and the overbite was 0.5 mm. Class II molar and canine
relationships were noted on both sides. Maxillary and man- dibular dental midlines were coincident with the facial
midline. Lingual crossbite was pointed out at the maxillary
and mandibular right lateral incisors. The arch length dis- crepancy was 1 mm in the maxillary arch and 3 mm in the
mandibular arch. The maxillary right first molar had severe
dental caries. Cantilevered porcelain fused to the metal
prosthesis with bilateral maxillary central incisors as abut- ments and a pontic at the maxillary left lateral incisor, and
two additional ill-fitted metal crowns were observed on
the bilateral mandibular first molars. Her general health
was good, and she reported no chronic systemic diseases.
Cephalometric analysis revealed a skeletal Class II rela- tionship (SNA, 84.0°; SNB, 76.0°; ANB, 8.0°) and high man- dibular plane angle (SN-MP, 42.6°) (Fig 3; Table). The
maxillary incisors were retroclined (U1-SN, 95.7°), and
mandibular incisors were proclined (L1-MP, 97.8°), which
were typical dental compensations for skeletal Class II
relationships. Both upper and lower lips were positioned in
front of the E-line by quite a bit (UL-E line, 10.5 mm; LL-E
line, 16.5 mm). A panoramic radiograph showed the man- dibular right third molar and maxillary left lateral incisor to
be missing. The maxillary right first molar had severe den- tal caries and was hopeless. Root canal fillings were inade- quate in her maxillary central incisors and mandibular
right first molar. A periapical lesion was noted at the man- dibular right first molar.
The diagnosis was skeletal Class II high mandibular
plane angle, bimaxillary protrusion with upright maxillary
incisors, and proclined mandibular incisors. Although the
patient’s maxillary incisors were upright, both the upper
and lower lips were far ahead of the E-line, which indicated
that the protrusion was more due to skeletal issues than
dental issues.
TREATMENT OBJECTIVES
The treatment objectives were maximal retraction to
reduce the protrusion, removal of the teeth with poor
prognosis, and rehabilitation of functional occlusion. If the
spaces could not be totally closed by orthodontic space
closure, prosthetic restorations would be necessary to
restore the integrity of the dentition.
TREATMENT ALTERNATIVES
The first treatment option was to extract four first pre- molars, remove the hopeless maxillary right first molar,
remaining third molars, and undergo orthognathic surgery
(maxillary setback, mandibular advancement, and optional
genioplasty).6 Two dental implants would be required for
the extraction space of the maxillary right first molar, and
the missing maxillary left lateral incisor. All the old pros- theses would be replaced after orthodontic treatment.
The second treatment option was to extract the maxillary
first premolars and mandibular second premolars and
remove the hopeless maxillary right first molar and remain- ing third molars.7,8 Maxillary posterior TSADs were planned
for Class II correction and maximal retraction. Two dental
implants would be necessary to restore the spaces left by
the extracted maxillary right first molar, and the missing
maxillary left lateral incisor. All the old prostheses would be
replaced after orthodontic treatment. Instead of four first
premolar extractions, the extraction pattern in option 2 might
provide safer control of Class II correction if the TSADs were
not as successful as planned.
The third treatment option was the same as option 2,
except the extraction space of the maxillary right first
molar would be closed orthodontically. The maxillary right
third molar would be kept as a substitute for the maxillary
right second molar. Only one dental implant was required
for the missing maxillary left lateral incisor. In consider- ation of the patient’s protrusive facial profile, it seemed
beneficial to retract more by closing the extraction space
of the maxillary right first molar. However, dental midline
deviation might be expected with asymmetrical space
Fig 3. Pretreatment lateral cephalogram and panoramic
radiograph.
Liaw et al.
December 2021, Vol 1, Issue 4 247
Page 4 of 14
closure, and midline control would require the use of
TSADs. For more anterior retraction, anterior TSADs might
be necessary for antibowing during maximal retraction.
For more maxillary retraction, we might also need TSADs
on the buccal shelves for more mandibular retraction to
match the maxillary arch. However, this option would
greatly rely on anchorage control with TSADs. Periodontal
surgery might be necessary to restore the appropriate
crown length and gingival line after significant intrusion
and retraction of the anterior teeth.
A treatment plan combined with orthognathic surgery
was first proposed to the patient to achieve the best possi- ble esthetic improvement and functional occlusion, but
the patient declined the surgical approach. As a result, the
author decided to attempt extraction treatment with TSADs
for maximal retraction as camouflage treatment for the
severe skeletal Class II, high angle and retruded chin.
Unfortunately, the treatment plan was complicated by the
hopeless maxillary right first molar. We understood that
closing the molar space would result in different outcomes
with a more pleasant facial profile or a more protrusive
facial profile and an additional dental implant. However,
the risks for asymmetrical space closure included dental
midline deviation, deepbite, and incisor torque loss
because of the bowing effect and mismatched interarch
relationships. In addition, it would take longer to close the
extra molar space.
After a detailed discussion with the patient, option 3
was determined in the end.
TREATMENT PROGRESS
Before orthodontic treatment commenced, a prostho- dontist removed the splinted prostheses and fabricated
provisional crowns on the central incisors, restoring the
original morphology, position, and angulation of these
teeth (Fig 4).
A modified Alexander prescription was used. The slot
size for the anterior teeth (canine to canine) was 0.018-in,
whereas it was 0.022-in for the posterior teeth. The initial
archwire on the maxillary arch was a 0.016 £ 0.022-in
superelastic nickel-titanium (NiTi) wire intended to align
teeth and prevent the spinning of the esthetic pontic for
the missing maxillary left lateral incisor at the start of
treatment. Two weeks after bonding, two miniscrews (A1-
J, 2.0 £ 10 mm, Bioray Biotech Corporation, Taipei, Tai- wan) were installed in the maxillary posterior areas (infra- zygomatic crests). Bilateral elastic chains were attached
from the miniscrews to the canine brackets for canine
retraction. One month later, mandibular brackets were
bonded, and leveling was started with a 0.016-in NiTi arch- wire.
The space closure began one month after the
0.016 £ 0.022-in stainless steel archwires were placed on
both arches. Maxillary posterior TSADs were used for maxi- mal retraction. As the anterior teeth were retracted, the
overbite increased as the incisor torque was lost gradually.
To control the overbite and incisor torque, another two
subapical miniscrews (A1-J-head cut, 2.0 £ 10 mm, Bioray
Biotech Corporation) were inserted in the subapical areas
Table. Cephalometric measurements
Analysis Norms Pretreatment Posttreatment 10 y, 3 mo follow-up
Skeletal
SNA (°) 81.5 § 3.5 84.0 84.0 84.0
SNB (°) 77.7 § 3.2 76.0 77.0 77.0
ANB (°) 4.0 § 1.8 8.0 7.0 7.0
SN-MP (°) 33.0 § 1.8 42.6 38.9 39.0
Dental
U1-NA (mm) 3.9 § 2.1 2.5 4.0 2.0
U1-SN (°) 108.2 § 5.4 95.7 90.9 99.0
L1-NB (mm) 6.6 § 2.8 13.0 4.0 6.0
L1-MP (°) 96.8 § 6.4 97.8 83.5 87.4
Facial
E-LINE UL (mm) 1.1 § 2.2 10.5 4.5 6.5
E-LINE LL (mm) 0.5 § 2.5 16.5 9.0 13.0
Liaw et al.
248 AJO-DO CLINICAL COMPANION
Page 5 of 14
Fig 4. Provisional crowns were fabricated to restore the original shape and angulation of the maxillary central incisors. An esthetic
pontic was hung on the initial rectangular archwire for esthetics.
Fig 5. The records after 20 months of treatment showed a remaining molar-size space at the maxillary right quadrant, but the facial
profile was still very protrusive. Two miniscrews were installed on the buccal shelves for whole mandibular arch retraction.
Liaw et al.
December 2021, Vol 1, Issue 4 249
Page 6 of 14
of the maxillary and mandibular incisors with the extension
hooks made of 0.012-in stainless steel ligature wires. The
intrusive forces provided by the elastic chains from the
extension hooks anchored by the subapical miniscrews to
the archwires would reduce the overbite and reinforce the
labial crown torque on the anterior teeth.
After 20 months of treatment, the extraction spaces
were mostly closed except in the upper right quadrant, but
the patient’s profile had not improved sufficiently (Fig 5).
Besides, the positive overjet seemed insufficient, so two
buccal shelf miniscrews (A1-J, 2.0 £ 10 mm, Bioray Bio- tech Corporation) were installed on both sides for further
retraction of the mandibular arch. In the 41st month of
treatment, all spaces were closed, and bilateral canine
and molar Class I relationships were achieved. Full arch
retraction of the mandibular arch was continued with the
buccal shelf TSADs, whereas the infrazygomatic TSADs
were applied asymmetrically to correct the maxillary den- tal midline. After that, we moved to the finishing stage.
The periodontist performed periodontal surgery, including
crown lengthening and osseous reduction in the 44th
month of treatment (Fig 6). Before full mouth debonding,
the second set of provisional crowns were made for the
maxillary incisors.
After the final detailing, all appliances were removed
after 49 months of active treatment (Fig 7). A dental
implant and an implant-supported crown restored the
maxillary left lateral incisor after debonding (Fig 8). Full
mouth rehabilitation was completed 9 months after
debonding (Figs 9-11).
TREATMENT RESULTS
The bimaxillary protrusion was significantly reduced,
and the muscle strain was greatly relieved. The patient’s
facial profile was much more pleasant, with a significant
improvement on the chin projection. Both maxillary and
mandibular arches were well-aligned with good interdigita- tion. The Class II malocclusion was corrected to Class I
relationships with all extraction spaces closed except for
the maxillary left lateral incisor restored by an implant- supported full ceramic crown. Maxillary central incisors
and mandibular first molars were restored with new full
ceramic crowns, and dental midlines were coincident. The
facial profile had become even more relaxed than at
debonding. This might be due to the functional adaptation
of the soft tissues after the hard tissues were corrected.
Superimposed cephalometric tracings before and after
treatment can be seen in Figure 12, and a summary of
cephalometric measurements is provided in Table. The
maxillary central incisors were retracted by 8.3 mm, with
1.5 mm of intrusion at the incisal edges and 2.1 mm at the
apices. The maxillary buccal segments were distalized by
1 mm, with 1 mm of intrusion at the maxillary first molar.
The mandibular incisors were retracted by 9.8 mm, with
2.2 mm of intrusion at the incisal edges and 3.9 mm at the
apices. The mandibular first molars were mesialized by
2.8 mm, with 3.2 mm of intrusion. The lower anterior facial
height was decreased by 4.1 mm. The mandibular plane
angle was reduced by 3.7° from 42.6° to 38.9°. Counter- clockwise rotation of the mandible made the SNB increase
Fig 6. The crown length of the maxillary anterior became very short because of a great amount of retraction and intrusion. To regain
better crown proportions and eliminate the irregular bony contour, periodontal surgery, including soft tissue and bone reduction, was
performed at the finishing stage. A, At the 44th month of treatment; B, After periodontal surgery; C, After 1 month of healing; D, The
second set of provisionals before debonding; E, Debonding before implant placement; F, Definitive prostheses, 9 months after
debonding.
Liaw et al.
250 AJO-DO CLINICAL COMPANION
Page 7 of 14
Fig 7. Facial and intraoral photographs at debonding after 49 months of treatment.
Fig 8. Prosthetic rehabilitation after debonding was completed in 9 months.
Liaw et al.
December 2021, Vol 1, Issue 4 251
Page 8 of 14
Fig 9. Posttreatment facial and intraoral photographs, 9 months after debonding to finish the prosthetic restorations.
Fig 10. Posttreatment study models.
Liaw et al.
252 AJO-DO CLINICAL COMPANION
Page 9 of 14
by 1° from 76° to 77°, which reduced the ANB by 1°, conse- quently, from 8° to 7°.
RETENTION
Maxillary and mandibular vacuum-formed clear
retainers were delivered, and the patient was instructed to
wear them full-time for the first six months and then only
at night after that point. In addition, the patient was
instructed in proper home hygiene and maintenance of the
retainers. Particular emphasis was placed on retention
because of the significant amount of tooth movement dur- ing treatment. She was informed that the more we move
teeth, the stronger the tendency is for relapse unless she
is diligent in wearing her retainers.9 Her overall compliance
seemed to be good for the first five years of retention (Fig
13). However, there appeared to be a break during the
sixth year after debonding for the implant restoration
replacing the fractured mandibular right first molar. Using
the implant prosthesis of the maxillary left lateral incisor
as a reference, there was obvious relapse by the labial
movement of the adjacent anterior teeth (Fig 14). Consis- tent retainer wear every night was advised.
DISCUSSION
The preferred method when treating a Class II high
angle patient with severe bimaxillary protrusion and a ret- ruded chin is orthognathic surgery, but if the patient
rejects surgical intervention, the extraction of four
Fig 11. Posttreatment lateral cephalogram and panoramic
radiograph.
Fig 12. Cephalometric superimpositions showed maximal retraction of incisors and counterclockwise rotation of the mandible to
improve the chin projection. It also showed some relapse at the 10 years, 3 months follow-up leading to increased mentalis strain and
lower lip protrusion.
Liaw et al.
December 2021, Vol 1, Issue 4 253
Page 10 of 14
premolars and use of TSADs can provide suitable treat- ment results. The airway should always be considered in
patients that need a large amount of incisor retraction.10-12
Orthodontic treatment combined with orthognathic sur- gery was recommended in consideration of the airway
issue. The patient did not suffer from obstructive sleep
apnea throughout the orthodontic treatment, even though
the anteroposterior dimension of her airway was reduced
after orthodontic treatment, as seen in the 2-dimensional
lateral cephalogram. These results were in concert with an
American Association of Orthodontists White Paper,13
which states that changes in the upper airway dimensions
after orthodontic treatment do not necessarily result in a
change in airway function. Our patient did not report a
sleep problem at a long-term follow-up.
In addition to severe dentoalveolar protrusion, the
patient also had thick lips, making the profile improvement
more difficult.3,4,14 Her facial profile changes at 20 months
into treatment showed insufficient reduction even though
most of the spaces had been closed except those in the
maxillary right quadrant (Fig 5). Maxillary dental midlines
tended to shift to the right during space closure, so the
maxillary left miniscrew was critical for midline control by
distalizing the maxillary left quadrant while closing the
space in the maxillary right quadrant. In the meantime, the
TSADs in the bilateral buccal shelves were also very impor- tant for total arch distalization of the mandibular dentition
to maintain an appropriate overjet during maximal retrac- tion of the maxillary incisors. Her profile improved signifi- cantly, but her lower lip was still thick at debonding
(Fig 7). After 9 months of prosthetic rehabilitation, her
facial profile improved, and her lower lip seemed to be
thinner (Fig 9). The soft tissues might shrink several
months after orthodontic treatment has been completed.
This might have been due to neuromuscular adaptation to
the hard tissue changes. Records at 4 years, 11 months
showed reasonably good stability (Fig 13); however, the
patient’s mandibular right first molar was extracted
because of a vertical root fracture. A dental implant was
installed 6 months later. The 10 years, 3 months follow-up
records showed some relapse (Fig 14). The maxillary left
lateral incisor was in a crossbite. The lower lip was pro- truded, and everted and mentalis strain had reappeared.
The lateral cephalometric superimpositions showed the
forward movement of both the maxillary and mandibular
incisors by 1.7 mm and the extrusion of the mandibular
Fig 13. Follow-up records at 4 years, 11 months after debonding.
Liaw et al.
254 AJO-DO CLINICAL COMPANION
Page 11 of 14
incisors by 1.6 mm (Fig 12). The maxillary right second
molars moved forward by 0.7 mm and downward by
0.5 mm. The mandibular plane angle was increased by
0.1°, from 38.9° to 39.0°. The progressive facial profile
changes deserved our attention on anchorage control, soft
tissue response, vertical control, and relapse (Fig 15).
All orthodontists should know that avoiding molar
extrusion and mandibular plane angle open-up is critical
for patients with high angles. With the aid of TSADs, we
can reduce the need for interarch elastics, especially Class
II elastics, which may lead to mandibular molar extrusion
and worsen the patient’s facial profile.15-17 Active vertical
control can be achieved with combined intrusion and
retraction force systems supported with TSADs on both
arches, which results in counterclockwise rotation of the
mandible (Fig 16). It was beneficial for our patient who had
a severe convex profile and retruded chin. To achieve
active vertical control, the combined intrusion and retrac- tion force system only on the maxillary arch may not
always be good enough as compensatory supereruption of
the mandibular molars may impede the counterclockwise
rotation of the mandible. Combined intrusion and
retraction force systems on both arches provide the best
opportunity to achieve successful active vertical control.
At the initial consultation, patients must be informed
about the possibility that they will need periodontal
surgery.18,19 If the retraction and intrusion of the anterior
teeth are relatively large in amount, the clinical crowns of
these teeth will be shortened, and the bony contour will
become more prominent and protruding like exostoses
because of insufficient bone remodeling after the tooth
movement. As a result, periodontal surgery, including
crown lengthening and alveoloplasty, will be necessary to
reestablish the ideal proportions of these teeth and
smooth the bony contour (Fig 6). Furthermore, on the
basis of the flap elevation findings, the root prominence of
the maxillary incisors was very obvious at the palatal corti- cal plate and the site of the implant fixture on the alveolar
ridge at the maxillary left lateral incisor was more labial
than the rest of the maxillary incisors. There was a bony
fenestration after the implant installation to match the
labiolingual position of the implant position with other
maxillary incisors after orthodontic retraction. An autoge- nous bone graft from the labial cortical bone reduction
Fig 14. Ten years and three months follow-up records showed some relapse. The maxillary left lateral incisor was in a crossbite
relationship with the mandibular left lateral incisor.
Liaw et al.
December 2021, Vol 1, Issue 4 255
Page 12 of 14
and demineralized freeze-dried bone allograft was per- formed at the palatal alveolar bone of maxillary incisors. It
took quite a while for the palatal wound to heal. At a fol- low-up examination, the periodontal situation looked good
with no gingival recession or increase in pocket depths.
Although complete space closure was attempted for
the maximal retraction of the facial profile, when the space
had been closed in the mandibular arch, there were still
some spaces in the maxillary arch (Fig 5). The overjet was
insufficient for further retraction in the maxillary arch. The
remaining spaces could be closed either by the forward
movement of the maxillary posterior teeth without further
retraction of the mandibular dentition or by maximal
retraction of maxillary anterior teeth to fit with the mandib- ular incisors after total arch distalization of the mandibular
dentition. To maximize the facial profile retraction, it was
decided to install TSADs on the buccal shelves for total
arch distalization of the mandibular dentition so that the
remaining space in the maxillary arch could be closed in
favor of the profile improvement.
However, a space of 1.5 mm was left distal the
esthetic pontic of the maxillary left lateral incisor in the
final stage after the maxillary and mandibular dental
midlines were coincident, and bilateral molar relation- ships were Class I. The decision to retain this space was
discussed between the orthodontists and the prostho- dontist. The orthodontists were reluctant to close the
space because doing so would worsen the occlusion on
the left side and pull the canine away from its solid Class
I position. The orthodontists suggested redistributing the
space to enlarge the maxillary central incisors and the
left lateral incisor evenly, but the prosthodontist did not
think this was a good idea because it would worsen the
proportions of the central incisors and make them
appear to be more square. In the end, the prosthodontist
agreed to enlarge the maxillary left canine by adding
composite resin on the mesial surface and moving the
distal line angle of the lateral incisor mesially to create
an illusion of narrowing while maintaining the proper
crown proportions (Fig 17).
Fig 15. Progressive facial profile changes. A, Pretreatment; B, 20 months of treatment when most of the spaces were closed except
the maxillary right quadrant. C, Debonding; D, Posttreatment; E, 4 years, 11 months after debonding; F, 10 years, 3 months after
debonding.
Liaw et al.
256 AJO-DO CLINICAL COMPANION
Page 13 of 14
CONCLUSIONS
With the aid of TSADs, a patient with severe bimaxillary
protrusion and high mandibular plane angle can be treated
by extracting four premolars and one maxillary molar to
achieve good results without orthognathic surgery. In
treating patients with high angles, vertical control is criti- cal. Effective molar intrusion can be achieved by the com- bined intrusion and retraction force systems on both
arches supported with TSADs, resulting in counterclock- wise rotation of the mandible. It is important to remember
Fig 16. Both arches’ combined intrusion and retraction force systems tended to move the maxillary occlusal plane upward and
mandibular occlusal plane downward. It is possible to rotate the mandible counterclockwise to achieve active vertical control and
improve the chin projection.
Fig 17. Illusion technique was applied during the crown fabrication of the maxillary left lateral incisor. A and B, Space was left distal to
the maxillary left lateral incisor; C, Widening illusion; D and E, Definitive prostheses were in place using narrowing illusion to make
maxillary lateral incisors looked more symmetrical in size; F, Narrowing illusion.
Liaw et al.
December 2021, Vol 1, Issue 4 257
Page 14 of 14
that reasonably good results can only be achieved by com- prehensive interdisciplinary approaches to optimize the
final esthetics.
ACKNOWLEDGMENTS
The authors wish to thank the prosthodontist, Dr Yi Ho,
and the periodontist, Dr Shih-Jung Lin, for their expertise
and collaboration to achieve the best possible results for
this patient.
AUTHOR CREDIT STATEMENT
Johnny J.L. Liaw contributed to supervision and original
draft preparation; Jae Hyun Park: contributed to original
draft preparation and manuscript review and editing; Irene
Yi-Hong Shih contributed to treatment and original draft
preparation; Stella Ya-Huei Young contributed to treatment
and original draft preparation; Fang-Fang Tsai contributed
to treatment and original draft preparation.
REFERENCES
1. Baek SH, Kim BH. Determinants of successful treatment of
bimaxillary protrusion: orthodontic treatment versus ante- rior segmental osteotomy. J Craniofac Surg 2005;16:234–
46.
2. Bills DA, Handelman CS, BeGole EA. Bimaxillary dentoal- veolar protrusion: traits and orthodontic correction. Angle
Orthod 2005;75:333–9.
3. Rains MD, Nanda R. Soft-tissue changes associated with
maxillary incisor retraction. Am J Orthod 1982;81:481–8.
4. Talass MF, Talass L, Baker RC. Soft-tissue profile changes
resulting from retraction of maxillary incisors. Am J
Orthod Dentofacial Orthop 1987;91:385–94.
5. Cope JB. Temporary anchorage devices in orthodontics: a
paradigm shift. Semin Orthod 2005;11:3–9.
6. Chu YM, Bergeron L, Chen YR. Bimaxillary protrusion: an
overview of the surgical-orthodontic treatment. Semin
Plast Surg 2009;23:32–9.
7. Tan TJ. Profile changes following orthodontic correction of
bimaxillary protrusion with a preadjusted edgewise appli- ance. Int J Adult Orthodon Orthognath Surg 1996;11:239–51.
8. Kook YA, Park JH, Bayome M, Sa’aed NL. Correction of
severe bimaxillary protrusion with first premolar extrac- tions and total arch distalization with palatal anchorage
plates. Am J Orthod Dentofacial Orthop 2015;148:310–20.
9. Melrose C, Millett DT. Toward a perspective on orthodon- tic retention? Am J Orthod Dentofacial Orthop
1998;113:507–14.
10. Chen Y, Hong L, Wang CL, Zhang SJ, Cao C, Wei F, et al.
Effect of large incisor retraction on upper airway morphol- ogy in adult bimaxillary protrusion patients. Angle Orthod
2012;82:964–70.
11. Wang Q, Jia P, Anderson NK, Wang L, Lin J. Changes of pha- ryngeal airway size and hyoid bone position following ortho- dontic treatment of Class I bimaxillary protrusion. Angle
Orthod 2012;82:115–21.
12. Hu Z, Yin X, Liao J, Zhou C, Yang Z, Zou S. The effect
of teeth extraction for orthodontic treatment on the
upper airway: a systematic review. Sleep Breath
2015;19:441–51.
13. Behrents RG, Shelgikar AV, Conley RS, Flores-Mir C, Hans
M, Levine M, et al. Obstructive sleep apnea and orthodon- tics: an American Association of Orthodontists White
Paper. Am J Orthod Dentofac Orthop 2019;156:13–28. e1.
14. Yogosawa F. Predicting soft tissue profile changes concur- rent with orthodontic treatment. Angle Orthod
1990;60:199–206.
15. Lee J, Miyazawa K, Tabuchi M, Kawaguchi M, Shibata M,
Goto S. Midpalatal miniscrews and high-pull headgear for
anteroposterior and vertical anchorage control: cephalo- metric comparisons of treatment changes. Am J Orthod
Dentofacial Orthop 2013;144:238–50.
16. Wang XD, Zhang JN, Liu DW, Lei FF, Liu WT, Song Y, et al.
Nonsurgical correction using miniscrew-assisted vertical
control of a severe high angle with mandibular retrusion
and gummy smile in an adult. Am J Orthod Dentofacial
Orthop 2017;151:978–88.
17. Oueis R, Waite PD, Wang J, Kau CH. Orthodontic-Orthog- nathic Management of a patient with skeletal class II with
bimaxillary protrusion, complicated by vertical maxillary
excess: A multi-faceted case report of difficult treatment
management issues. Int Orthod 2020;18:178–90.
18. Yodthong N, Charoemratrote C, Leethanakul C. Factors
related to alveolar bone thickness during upper incisor
retraction. Angle Orthod 2013;83:394–401.
19. Eksriwong T, Thongudomporn U. Alveolar bone response
to maxillary incisor retraction using stable skeletal struc- tures as a reference. Angle Orthod 2021;91:30–5.
Liaw et al.
258 AJO-DO CLINICAL COMPANION