- Email: [email protected]
Camouflage of a high-angle skeletal Class II open-bite malocclusion in an adult after mini-implant failure during treatment
CASE REPORT
Camouflage of a high-angle skeletal Class II open-bite malocclusion in an adult after mini-implant failure during treatment Eduardo Franzotti Sant’Anna,a Amanda Carneiro da Cunha,a Daniel Paludo Brunetto,a and Claudia Franzotti Sant’Annab Rio de Janeiro, Brazil The treatment of skeletal anterior open-bite malocclusion requires complex orthodontic planning that considers its multifactorial etiology, treatment limitations, and high relapse rates. This case report illustrates a successful treatment approach for a skeletal high-angle Class II malocclusion in an adult with a severe open bite. The treatment consisted of a high-pull headgear therapy after mini-implants failure during fixed orthodontic therapy. Adequate esthetics and function were achieved. Despite its low probability, the unexpected event of miniimplant loosening during complex treatments should be considered. Therefore, classic orthodontic mechanics should be established, especially when treating patients for whom invasive procedures such as miniplates or orthognathic surgery are not available options. (Am J Orthod Dentofacial Orthop 2017;151:583-97)
S
keletal anterior open-bite malocclusions require a complex orthodontic therapy that considers their multifactorial etiology, treatment limitations, and high relapse rates.1-3 A rigorous investigation of the open-bite etiology is the first step toward the treatment plan. The classical factors associated with this condition include functional factors (inappropriate muscle growth or activity, neurologic and respiratory disabilities), habitual factors,4 and dental and skeletal components.2 High-pull headgear,1 vertical chincups,5 posterior bite-blocks,6 habitbreaking appliances,5 fixed appliances,7 and orthognathic surgery8 are some traditional treatment modalities reported. The patient's age is a determinant for treatment once, in the early stages, it is possible to control the vertical growth of the alveolar process and the consequences of oral habits.9 The main a Department of Pedodontics and Orthodontics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. b Private practice, Rio de Janeiro, Brazil. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Address correspondence to: Eduardo Franzotti Sant’Anna, Department of Pedodontics and Orthodontics, Universidade Federal do Rio de Janeiro, Avenida Professor Rodolpho Paulo Rocco, 325, Ilha do Fund~ao, Rio de Janeiro, RJ, Brazil 21941-617; e-mail, [email protected]. Submitted, August 2014; revised and accepted, January 2016. 0889-5406/$36.00 Ó 2016 by the American Association of Orthodontists. All rights reserved. http://dx.doi.org/10.1016/j.ajodo.2016.01.020
limitation of conventional orthodontics in nongrowing patients is the establishment of a rigid anchorage for molar intrusion,10 which normally calls for a surgicalorthodontic approach to intrude the posterior maxillary arch segments, reducing the lower facial height.11 Skeletal anchorage systems provide an alternative for less invasive treatment of patients with severe anterior open-bite malocclusions because of the possibility of occlusal and mandibular plane alterations upon the intrusion of posterior teeth. With this system, it is possible to control the anterior tooth extrusion, which is more susceptible to root resorption and relapse.12,13 Successful outcomes have been reported concerning the treatment of anterior open-bites with mini-implants4,14,15 and miniplates.10,12 This case report illustrates a 23-month follow-up of a nonsurgical approach for a patient with a high-angle skeletal Class II open-bite malocclusion. She was treated with premolar extractions and posterior tooth intrusion with mini-implants that failed during maxillary incisor leveling and were replaced by a hyrax expander associated with high-pull headgear.
DIAGNOSIS AND ETIOLOGY
A young woman, aged 18 years and 11 months, sought treatment in the Department of Orthodontics at the Federal University of Rio de Janeiro in Brazil, 583
Franzotti Sant’Anna et al
584
Fig 1. Pretreatment facial and intraoral photographs.
with an anterior open bite and symptoms of temporomandibular disorders; she reported occasional pain in the temporomandibular joints (TMJ) during mastication. During the TMJ clinical examination, bilateral crepitation and pain upon masseter muscle palpation were observed. There was history of a pacifier sucking habit until the age of 7 years. At initial orthodontic appointment, she did not report any medical intercurrence, and she was not taking any medication. However, 1 year later, she underwent medical treatment for a nutritional deficiency. She weighed 43 kg and was 1.61 m tall. Initial facial analysis indicated vertical growth with mild facial asymmetry toward the right side, a convex profile, increased lower facial third, and the absence of passive lip sealing with increased mentalis muscle activity with closed lips (Fig 1). As for the functional aspects, there was improper tongue posture with atypical speech and swallowing. The intraoral clinical
March 2017 Vol 151 Issue 3
examination and analysis of the initial cast models showed an Angle Class II Division 1 malocclusion, maxillary and mandibular anterior crowding (9 mm), V-shaped maxillary and quadratic mandibular dental arches, overjet of 9 mm, and anterior open bite of 5 mm. The maxillary and mandibular dental midlines were deviated 0.5 mm to the left and 2 mm to the right from the facial midline, respectively (Figs 1 and 2; see Video 1, available at www.ajodo.org). The pretreatment panoramic radiograph showed narrow and asymmetric condyles (the left condyle was larger than the right condyle) and the presence of all 4 unerupted third molars (Fig 3). Additionally, by analyzing the cone-beam computed tomography (CBCT) images, we observed that the mandibular dental midline deviation might have been influenced by the asymmetric growth of the condyles and the mandible. Cephalometric analysis indicated a Class II skeletal relationship due to mandibular retrusion (ANB, 8.0 ; SNB, 73.9 ), vertical
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
585
Fig 2. A, Pretreatment digital 3D dental casts; B, plaster dental casts set up for the surgical planning.
Fig 3. Pretreatment panoramic radiograph. Note the reduced volume and dimension of the right condyle.
facial growth pattern (y-axis, 66.2 ) with a steep mandibular plane angle (GoGn.SN, 43.8 ; FMA, 39.8 ), and projected and protruded maxillary and mandibular incisors (Fig 4, Table). TREATMENT OBJECTIVES
Based on the diagnostic records, the treatment objectives were as follows: (1) establish a functional occlusion by normalizing overjet and overbite relationships, (2) improve the facial profile, (3) solve the crowding in both arches, (4) coordinate the maxillary and mandibular arches, (5) reduce the lower facial third height, and (6) obtain passive lip sealing and proper tongue posture. TREATMENT ALTERNATIVES
The combined approach of orthodontic treatment and bimaxillary orthognathic surgery (involving
maxillary posterior impaction and mandibular counterclockwise rotation and advancement) with extraction of all third molars and first premolars was first considered because of the effectiveness and predictability of this treatment modality to reduce skeletal open bites. However, this alternative was discarded by the patient, and her parents refused to have their daughter undergo any surgical procedure. The second alternative was a dentoalveolar camouflage treatment with an orthodontic fixed appliance, with extraction of all third molars and first premolars and the use of mini-implants to provide anchorage to intrude the posterior teeth in both arches. After carefully considering that molar intrusion with a likely counterclockwise rotation of the mandible could result in a desirable effect for the patient's facial profile, the second alternative was chosen. The patient and parents were repeatedly advised that the first option was
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
586
Fig 4. A, Pretreatment cephalometric x-ray; B, pretreatment cephalometric tracing. Black, blue, and green lines indicate Steiner, Tweed, and Downs analyses respectively. Table. Pretreatment and posttreatment cephalo-
metric measurements 23-month Pretreatment Posttreatment follow-up SNA angle ( ) 81.9 82.2 81.5 SNB angle ( ) 73.9 74.1 73.5 8.0 8.2 8.0 ANB angle ( ) SND angle ( ) 71.1 71.5 71.4 1:NA (mm) 16.9 1.4 1.8 1:NA ( ) 28.7 11.1 11.4 1:NB (mm) 16.2 16.8 16.5 1:NB ( ) 25.2 28.4 29.6 Pog:NB (mm) 0.1 11.2 11.3 IMPA ( ) 84.3 90.1 90.5 FMA ( ) 39.8 38.4 39.7 1:1 ( ) 118.1 132.3 131.0 Ocl:SN ( ) 12.9 29.2 28.6 43.8 41.1 41.8 GoGn:SN ( ) Upper lip to S line (mm) 13.0 1.5 1.7 Lower lip to S line (mm) 14.1 11.5 11.2 Y-axis ( ) 66.2 65.7 66.4
superior in terms of esthetic and functional outcomes, as well as the lack of predictability of the dentoalveolar camouflage. TREATMENT PROGRESS
Before the orthodontic treatment, all third molars were extracted. A standard 0.022-in edgewise appliance (Morelli, S~ao Paulo, Brazil) was banded and bonded to
March 2017 Vol 151 Issue 3
the maxillary and mandibular second premolars and the first and second molars. Habit spurs were bonded to the lingual surfaces of the maxillary and mandibular incisors to control tongue thrust. Six mini-implants (diameter, 1.4 mm; length, 6 mm; S.I.N. Implants System, S~ao Paulo, Brazil) were placed into the buccal and palatal alveolar bone between the maxillary second premolars and first molars and into the buccal alveolar bone between the mandibular second premolars and first molars on both sides. Sectional archwires of 0.017 3 0.025-in beta-titanium alloy and 0.018 3 0.025-in stainless steel were placed in the maxillary and mandibular arches, respectively, and intrusion of the posterior teeth started with elastomeric chains (100 gf). Then, after the extraction of the maxillary and mandibular first premolars, a 0.022-in edgewise appliance (Morelli, S~ao Paulo, Brazil) was bonded to the maxillary and mandibular anterior teeth, and leveling was started with a sequence of 0.012-in and 0.014-in nickel-titanium, and 0.016-in and 0.018-in continuous stainless steel archwires for the maxillary arch, while intrusive mechanics were continuously applied (Fig 5). A segmented 0.012-in nickel-titanium archwire was used to align the mandibular incisors, and then a 0.014-in stainless steel continuous archwire with loops was inserted to start leveling and aligning. Subsequently, a sequence of continuous 0.014-in, 0.016-in, and 0.018-in stainless steel archwires aligned and leveled the lower arch. Lower archwires were transversely contracted to counteract the expansion tendency caused
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
587
Fig 5. Full fixed edgewise appliance for alignment and leveling procedure.
Fig 6. The 0.018 3 0.025-in stainless steel sectional loop archwires for mandibular molar intrusion.
by the force exerted by the elastics attached to the buccal mini-implants. After 19 months of treatment, leveling of the anterior teeth and crowding resolution were achieved. Then, 2 additional bracket-head mini-implants (diameter, 1.4 mm; length, 8 mm; Sistema INP, S~ao Paulo, Brazil) were placed into the buccal alveolar bone between mandibular canine and second premolars, bilaterally, due to mini-implants failure in the previous sites. Then, 0.018 3 0.025-in stainless steel sectional
archwires with activated coil springs were used for molar intrusion (Fig 6). Because of the inability of the mini-implants to remain stable until the end of the intrusion mechanics, and after several and sequential loosening episodes, a conventional strategy of therapy with a high-pull headgear was implemented (Fig 7). To correct the transverse arch dimension discrepancy that settled in during treatment, a hyrax device was installed in the maxilla and activated 0.75 mm on the first day and 0.25 mm once a week for 14 weeks
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
588
Fig 7. A, High-pull headgear; B, hyrax appliance.
Fig 8. Intraoral photographs. The white arrows indicate the gingival hyperplasia surrounding the miniimplant during a loosening episode. Note that the only mini-implant that remained stable was the one between the mandibular left second premolar and first molar. From this moment on, conventional orthodontic therapy was adopted. An indirect mini-implant anchorage procedure was used to correct the mandibular midline.
Fig 9. Sliding jigs and Class II intermaxillary elastics. The elastics were attached to the mandibular second molars to increase the horizontal force vector.
(Fig 7). The transverse dimension control was performed gradually with progressive coordination of maxillary and mandibular archwires and elimination of premature contacts that contributed to the bite
March 2017 Vol 151 Issue 3
closure. The molars palatal cusps were also flattened with an oval diamond bur used at high speed to minimize occlusal interference. During the expansion, the high-pull headgear usage was not discontinued, and
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
589
Fig 10. Posttreatment facial and intraoral photographs.
the rigid frame of the hyrax prevented buccal tipping of maxillary molars. The inferior dental midline was corrected to the left by managing the residual extraction spaces. All mandibular mini-implants were lost with the exception of the one between the mandibular left second premolar and first molar, which was maintained to assist with the mandibular midline correction (Fig 8; see Video 2, available at www.ajodo.org). To control the tongue posture during treatment, the patient was instructed to maintain her tongue against the hard palate when swallowing and resting. The orthodontic finalization stage proceeded with a 0.019 3 0.025-in stainless steel archwire with lingual root torque compensations in the maxillary incisor region. Bilateral sliding jigs associated with Class II intermaxillary elastics were installed to
improve posterior intercuspation (Fig 9). The mechanical device with sliding jigs was installed to favor horizontal force direction with a decrease of posterior extrusive forces induced by Class II elastics. Front cross elastics (1/400 heavy) were used from the maxillary left canine to the mandibular right canine to improve the dental midlines and transverse interarch coordination. After fixed appliances removal, alginate impressions were poured to obtain models of the maxillary and mandibular arches. Essix retainers were thermoformed from 1 mm sheets (Dentsply, S~ao Paulo, Brazil) and cosmetic restorations. TREATMENT RESULTS
Posttreatment photographs and dental 3dimensional (3D) casts demonstrate the achievement
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
590
Fig 11. Posttreatment digital 3D dental casts.
Fig 12. Posttreatment panoramic radiograph.
of Class I molar and canine relationships, crowding resolution, harmonious dental arches, and dental midlines coinciding with the facial midline (Figs 10 and 11; see Video 3, available at www.ajodo.org). The panoramic evaluation showed minimal root resorption of the maxillary incisor apex and ideal root parallelism (Fig 12). The cephalometric outcomes indicate a slight counterclockwise rotation of the mandible, expressed by the decrease of the GoGn.SN angle from 43.8 to 41.1 at the final records (Fig 13).
March 2017 Vol 151 Issue 3
The facial profile was improved, and the mentalis muscle became less stressed at rest (Figs 14 and 15). An improper tongue posture habit was discontinued, and the patient's TMJs were asymptomatic for 23 months, although with persistent crepitation. The CBCT analysis of the region indicated a condyle aspect similar to that observed at the initial examination (Fig 16). Furthermore, the vertical and horizontal relationships of the incisors were successfully corrected and remained stabled over the 23-month follow-up period
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
591
Fig 13. A, Posttreatment cephalometric radiograph extracted from the CBCT; B, cephalometric tracing. Black, blue, and green lines indicate Steiner, Tweed, and Downs analyses respectively.
(Figs 17-19). The follow-up records (Fig 20) demonstrate that the periodontal health status was maintained as both teeth and bone tissue were properly preserved. Tracing superimpositions showed a decrease in lower facial height due to the intrusion of posterior teeth and counterclockwise rotation of the mandible (Figs 21 and 22), as well as significant maxillary incisor leveling, since they were in infraocclusion. DISCUSSION
Since skeletal open-bite malocclusions are frequently characterized by overeruption of posterior teeth, vertical control of dentoalveolar height during orthodontic treatment becomes a critical step.2 It is not questioned whether skeletal anchorage systems, especially miniimplants, enable the nonsurgical treatment of more severe cases.4,14,15 Mini-implant failure rate is approximately 13.5%16; in other words, the probability of an orthodontic mini-implant loosening is less than 1 in 5.17 This is a particular point to be noted because this case report dealt with recurrent mini-implant failure episodes and the impossibility of using other skeletal anchorage systems, such as miniplates or even orthognathic surgery, once the patient and her parents refused to invasive procedures. In addition, the patient systemic health condition presented another limitation to these alternative procedures. Faced with limited available treatment options, we decided to use the classical high-pull headgear associated with the hyrax dentoalveolar expander. The highpull strategy was considered because of the possibility
of intrusion, or at least to avoid extrusion, of the maxillary molars, with a possible counterclockwise mandibular rotation.18 The hyrax expander was used for maxillary transverse dimension correction. The posterior crossbite that was settled in during the treatment was, in part, related to the mini-implant mechanics of the inferior lower arch that caused some expansion, even with the contraction of all mandibular archwires during this phase of treatment. Furthermore, the maxillary arch had a transverse constriction that could be better visualized when the initial casts were manipulated to simulate the correction of the sagittal discrepancy. Slow maxillary expansion is recommended for adults with a transverse maxillary deficiency; yet it still involves risks such as relapse, pain, swelling, gingival recession, bone loss, and root resorption.19 By limiting our activation to 0.25 mm per week and anchoring the modified hyrax expander to 3 teeth on each side, we minimized these side effects. We controlled the natural tendency of the posterior dentition toward buccal crown inclination, which might lead to occlusal interference as the molars' palatal cusps are extruded. This controlled expansion along with the high-pull headgear curbed the vertical forces that could lead to clockwise rotation of the mandible and subsequent opening of the anterior bite that was previously reported by Sant’Anna et al.19 Justification for the use of CBCT images as a complementary examination procedure was provided by the information regarding the TMJ evaluation,20 accurate lateral cephalometry, frontal and panoramic
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
592
Fig 14. CBCT superimpositions: A, 3D translucent cranial base superimposition at the phase initial (green) and at posttreatment (yellow); B, axial slice of the maxillary arch, made on the 3D cranial base superimposition; C, midsagittal slice of the same superimposition; D, translucent soft tissue initial (white) and posttreatment (red) superimposition.
Fig 15. Profile comparisons: A, pretreatment; B, posttreatment; C, follow-up.
March 2017 Vol 151 Issue 3
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
593
Fig 16. CBCT sagittal and coronal 2-dimensional projections of the TMJs: A, pretreatment; B, posttreatment; C, follow-up. Note that the condyle asymmetry remained similar between these periods.
Fig 17. CBCT midsagittal slices: A, pretreatment; B, intermediate; C, posttreatment; D, follow-up. The lingual root torque of the maxillary incisors, observed from the intermediate to posttreatment and followup slices, allowed the counterclockwise movement of the chin.
2-dimensional projections,21 and orthognathic surgical planning.22 In addition to the preexisting TMJ dysfunction, the patient had other predisposing factors for condylar resorption: high mandibular plane angle; small condyles on long, slender condylar necks; and a female gender in the age range of 15 to 35 years.23,24 Since the orthodontic and orthopedic forces used during treatment could trigger alterations in condyle shape that could worsen her open bite, a careful TMJ
follow-up was performed.25 No evident alterations in condyles shape and volume were noticed in the TMJ projections images obtained from the CBCTs (Fig 16). Extraction of the 4 first premolars was essential to correct the full Angle Class II molar and canine relationships, change arch format, eliminate crowding in both arches, and correct the midline deviation and sagittal repositioning of the maxillary incisors. Improper tongue posture was an additional etiologic
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
594
Fig 18. Follow-up facial and intraoral photographs.
component of the malocclusion; therefore, spurs and speech therapy were implemented to reprogram the patient's neurologic consciousness of an adequate tongue rest position during treatment and the retention period.26 Our outcomes demonstrated that the objectives proposed were satisfactorily achieved because of the association of the treatment procedures and also the patient's excellent cooperation with the extraoral device. The cephalometric superimpositions (Fig 22) showed that more relevant changes were observed in the maxillary arch, which showed both molar intrusion and incisor extrusion. The occlusal plane became progressively steeper (Ocl:SN angle increased from 12.9 to 29.2 at the final records and to 28.6 at the follow-up records) as horizontal and vertical incisor overlaps were obtained. There was a moderate decrease of the mandibular plane
March 2017 Vol 151 Issue 3
angle (expressed by the GoGnSN angle reduction from 43.8 to 41 and retained at 41.8 ) that contributed to the anterior open-bite closure and the lower facial height reduction. This is supported by the fact that a small posterior intrusion (1 mm) can produce 3 to 4 mm of forward and upward movement of the chin.27 Although the mean relapse rate of molar intrusion mechanics is 22.8%,4 previous studies have reported that it did not influence the posttreatment skeletal and dental outcomes because of the maxillary incisors’ passive eruption as a compensatory mechanism.4,13 For further information regarding this aspect, we monitored the patient on a monthly basis for 23 months. The data indicated that the outcomes concerning the occlusion, condyle aspect, tongue posture habit, and periodontal status were stable over this period. Posterior intrusion was obtained
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
595
Fig 19. Follow-up digital 3D dental casts.
Fig 20. Follow-up panoramic radiograph.
with a combination of the mini-implant mechanics in the leveling phase and excellent use of the high-pull headgear. Although we have no medical evidence, we speculate that the nutritional deficiency, reflected in the poor quality of the bone (high porosity) observed during the insertion of the mini-implants, favored the molar intrusion movement because of reduced resistance. The upper lip was retracted 4.5 mm after the maxillary incisor retraction of 8.3 mm. Despite this amount of retraction, the analysis of the upper airway showed no important differences between either the initial and final volumes, or the initial and final minimal axial areas.28 Actually, the latter measurement, considering the most
important respiratory issues, had a slight increase from 89.7 to 101.9 mm2.29 These numbers should be read with care because airway measurements at different times, even for the same patient, are highly variable and can be influenced by breathing stage and head posture.30,31 It took us a great deal of time to progressively correct the inferior dental midline using the premolar space on the left side. This phase was the most time-consuming and difficult part of the treatment. After correcting the dental midline and adjusting the teeth to their correct positions (torque, leveling, distalization, and so on), the bite closed. No elastics were used to close the bite. Furthermore, we had intrusion of the posterior teeth (with mini-implants and high-pull headgear). Most of
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
596
Fig 21. A, Follow-up cephalometric radiograph extracted from CBCT; B, cephalometric tracing. Black, blue, and green lines indicate Steiner, Tweed, and Downs analyses respectively.
Fig 22. Superimposition of cephalometric tracings of pretreatment (black line), posttreatment (red line), and follow-up (green line) phases: A, superimposed on the sella-nasion plane at sella; B, superimposed on the palatal and mandibular planes.
the incisor extrusion was basically vertical during aligning and retraction because those teeth were in infraocclusion and proclined. Regarding the esthetic outcomes, the camouflage of a severe Class II open-bite malocclusion, with a hyperdivergent growth pattern, is a treatment with esthetic limitations when compared with the more beneficial surgical impacts on the facial profile and the patient's smile. However, this patient's esthetics were not
March 2017 Vol 151 Issue 3
compromised (gummy smile) by leveling the maxillary incisors, since they were in infraocclusion. In addition to this, there was an improvement in the perioral muscle balance expressed by significant attenuation of the mentalis strain (Fig 15). The several advantages of skeletal anchorage for the mini-implant based system justify the broadening of its application in orthodontic treatments. However, until all factors influencing mini-implant loosening are identified
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
and resolved, an alternative treatment option—in this case, extraoral and intraoral devices—should be at hand to achieve predictable and satisfactory treatment results.
597
14.
CONCLUSIONS
A severe high-angle skeletal Class II open-bite malocclusion was successfully treated with a nonsurgical conservative approach, using mini-implant skeletal anchorage followed by a conventional extraoral appliance and extraction of the first premolars. After miniimplants failure, the effective use of high-pull headgear associated with a hyrax appliance for molar intrusion and simultaneous incisor retraction provided a successful functional and esthetic improvement, as shown in the outcomes. SUPPLEMENTARY DATA
15.
16.
17. 18. 19. 20.
Supplementary data related to this article can be found online at http://dx.doi.org/10.1016/j.ajodo. 2016.01.020. 21. REFERENCES 1. Reichert I, Figel P, Winchester L. Orthodontic treatment of anterior open bite: a review article—is surgery always necessary? Oral Maxillofac Surg 2014;16:271-7. 2. Subtelny JD, Sakuda M. Open-bite: diagnosis and treatment. Am J Orthod 1964;50:337-58. 3. Greenlee GM, Huang GJ, Chen SS, Chen J, Koepsell T, Hujoel P. Stability of treatment for anterior open-bite malocclusion: a meta-analysis. Am J Orthod Dentofacial Orthop 2011;139:154-69. 4. Baek MS, Choi YJ, Yu HS, Lee KJ, Kwak J, Park YC. Long-term stability of anterior open-bite treatment by intrusion of maxillary posterior teeth. Am J Orthod Dentofacial Orthop 2010;138: 396.e1-9: discussion 396-8. 5. Huang GJ, Justus R, Kennedy DB, Kokich VG. Stability of anterior openbite treated with crib therapy. Angle Orthod 1990;60:17-24. 6. Kuster R, Ingervall B. The effect of treatment of skeletal open bite with two types of bite-blocks. Eur J Orthod 1992;14:489-99. 7. Kim YH. Anterior openbite and its treatment with multiloop edgewise archwire. Angle Orthod 1987;57:290-321. 8. Proffit WR, Bailey LJ, Phillips C, Turvey TA. Long-term stability of surgical open-bite correction by Le Fort I osteotomy. Angle Orthod 2000;70:112-7. 9. Buschang BH, Sankey W, English JP. Early Treatment of hyperdivergent open-bite malocclusions. Semin Orthod 2002;8:130-40. 10. Umemori M, Sugawara J, Mitani H, Nagasaka H, Kawamura H. Skeletal anchorage system for open-bite correction. Am J Orthod Dentofacial Orthop 1999;115:166-74. 11. Glenn G. An American Board of Orthodontics case report: the orthodontic-surgical correction of a Class II malocclusion with anterior open bite. Am J Orthod Dentofacial Orthop 1996;110:81-7. 12. Sherwood KH, Burch JG, Thompson WJ. Closing anterior open bites by intruding molars with titanium miniplate anchorage. Am J Orthod Dentofacial Orthop 2002;122:593-600. 13. Sugawara J, Baik UB, Umemori M, Takahashi I, Nagasaka H, Kawamura H, et al. Treatment and posttreatment dentoalveolar changes following intrusion of mandibular molars with applica-
22.
23.
24.
25.
26.
27. 28.
29.
30.
31.
American Journal of Orthodontics and Dentofacial Orthopedics
tion of a skeletal anchorage system (SAS) for open bite correction. Int J Adult Orthodon Orthognath Surg 2002;17:243-53. Heravi F, Bayani S, Madani AS, Radvar M, Anbiaee N. Intrusion of supra-erupted molars using miniscrews: clinical success and root resorption. Am J Orthod Dentofacial Orthop 2011;139(Suppl 4): S170-5. Deguchi T, Kurosaka H, Oikawa H, Kuroda S, Takahashi I, Yamashiro T, et al. Comparison of orthodontic treatment outcomes in adults with skeletal open bite between conventional edgewise treatment and implant-anchored orthodontics. Am J Orthod Dentofacial Orthop 2011;139(Suppl 4):S60-8. Papageorgiou SN, Zogakis IP, Papadopoulos MA. Failure rates and associated risk factors of orthodontic miniscrew implants: a metaanalysis. Am J Orthod Dentofacial Orthop 2012;142:577-95.e7. Stanford N. Mini-screws success rates sufficient for orthodontic treatment. Evid Based Dent 2011;12:19. Brown P. A cephalometric evaluation of high-pull molar headgear and face-bow neck strap therapy. Am J Orthod 1978;74:621-32. Sant'Anna EF, Marquezan M, Sant'Anna CF. Retreatment of an adult skeletal Class II patient. J Clin Orthod 2013;47:545-52. Librizzi ZT, Tadinada AS, Valiyaparambil JV, Lurie AG, Mallya SM. Cone-beam computed tomography to detect erosions of the temporomandibular joint: effect of field of view and voxel size on diagnostic efficacy and effective dose. Am J Orthod Dentofacial Orthop 2011;140:e25-30. Farman AG, Scarfe WC. Development of imaging selection criteria and procedures should precede cephalometric assessment with cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2006;130:257-65. Kapila S, Conley RS, Harrell WE Jr. The current status of cone beam computed tomography imaging in orthodontics. Dentomaxillofac Radiol 2011;40:24-34. Moore KE, Gooris PJ, Stoelinga PJ. The contributing role of condylar resorption to skeletal relapse following mandibular advancement surgery: report of five cases. J Oral Maxillofac Surg 1991;49:448-60. Kerstens HC, Tuinzing DB, Golding RP, van der Kwast WA. Condylar atrophy and osteoarthrosis after bimaxillary surgery. Oral Surg Oral Med Oral Pathol 1990;69:274-80. Peltola JS, Nystrom M, Kononen M, Wolf J. Radiographic structural findings in the mandibular condyles of young individuals receiving orthodontic treatment. Acta Odontol Scand 1995;53: 85-91. Bosio JA, Justus R. Treatment and retreatment of a patient with a severe anterior open bite. Am J Orthod Dentofacial Orthop 2013; 144:594-606. Kuhn RJ. Control of anterior vertical dimension and proper selection of extraoral anchorage. Angle Orthod 1968;38:340-9. Stefanovic N, El H, Chenin DL, Glisic B, Palomo JM. Three-dimensional pharyngeal airway changes in orthodontic patients treated with and without extractions. Orthod Craniofac Res 2013;16: 87-96. Vos W, De Backer J, Devolder A, Vanderveken O, Verhulst S, Salgado R, et al. Correlation between severity of sleep apnea and upper airway morphology based on advanced anatomical and functional imaging. J Biomech 2007;40:2207-13. El H, Palomo JM. Measuring the airway in 3 dimensions: a reliability and accuracy study. Am J Orthod Dentofacial Orthop 2010;137(Suppl 4):S50.e1-9: discussion S50-2. Mattos CT, Cruz CV, da Matta TC, Pereira Lde A, Solon-de-Mello Pde A, Ruellas AC, et al. Reliability of upper airway linear, area, and volumetric measurements in cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2014;145:188-97.
March 2017 Vol 151 Issue 3
Camouflage of a high-angle skeletal Class II open-bite malocclusion in an adult after mini-implant failure during treatment Eduardo Franzotti Sant’Anna,a Amanda Carneiro da Cunha,a Daniel Paludo Brunetto,a and Claudia Franzotti Sant’Annab Rio de Janeiro, Brazil The treatment of skeletal anterior open-bite malocclusion requires complex orthodontic planning that considers its multifactorial etiology, treatment limitations, and high relapse rates. This case report illustrates a successful treatment approach for a skeletal high-angle Class II malocclusion in an adult with a severe open bite. The treatment consisted of a high-pull headgear therapy after mini-implants failure during fixed orthodontic therapy. Adequate esthetics and function were achieved. Despite its low probability, the unexpected event of miniimplant loosening during complex treatments should be considered. Therefore, classic orthodontic mechanics should be established, especially when treating patients for whom invasive procedures such as miniplates or orthognathic surgery are not available options. (Am J Orthod Dentofacial Orthop 2017;151:583-97)
S
keletal anterior open-bite malocclusions require a complex orthodontic therapy that considers their multifactorial etiology, treatment limitations, and high relapse rates.1-3 A rigorous investigation of the open-bite etiology is the first step toward the treatment plan. The classical factors associated with this condition include functional factors (inappropriate muscle growth or activity, neurologic and respiratory disabilities), habitual factors,4 and dental and skeletal components.2 High-pull headgear,1 vertical chincups,5 posterior bite-blocks,6 habitbreaking appliances,5 fixed appliances,7 and orthognathic surgery8 are some traditional treatment modalities reported. The patient's age is a determinant for treatment once, in the early stages, it is possible to control the vertical growth of the alveolar process and the consequences of oral habits.9 The main a Department of Pedodontics and Orthodontics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. b Private practice, Rio de Janeiro, Brazil. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Address correspondence to: Eduardo Franzotti Sant’Anna, Department of Pedodontics and Orthodontics, Universidade Federal do Rio de Janeiro, Avenida Professor Rodolpho Paulo Rocco, 325, Ilha do Fund~ao, Rio de Janeiro, RJ, Brazil 21941-617; e-mail, [email protected]. Submitted, August 2014; revised and accepted, January 2016. 0889-5406/$36.00 Ó 2016 by the American Association of Orthodontists. All rights reserved. http://dx.doi.org/10.1016/j.ajodo.2016.01.020
limitation of conventional orthodontics in nongrowing patients is the establishment of a rigid anchorage for molar intrusion,10 which normally calls for a surgicalorthodontic approach to intrude the posterior maxillary arch segments, reducing the lower facial height.11 Skeletal anchorage systems provide an alternative for less invasive treatment of patients with severe anterior open-bite malocclusions because of the possibility of occlusal and mandibular plane alterations upon the intrusion of posterior teeth. With this system, it is possible to control the anterior tooth extrusion, which is more susceptible to root resorption and relapse.12,13 Successful outcomes have been reported concerning the treatment of anterior open-bites with mini-implants4,14,15 and miniplates.10,12 This case report illustrates a 23-month follow-up of a nonsurgical approach for a patient with a high-angle skeletal Class II open-bite malocclusion. She was treated with premolar extractions and posterior tooth intrusion with mini-implants that failed during maxillary incisor leveling and were replaced by a hyrax expander associated with high-pull headgear.
DIAGNOSIS AND ETIOLOGY
A young woman, aged 18 years and 11 months, sought treatment in the Department of Orthodontics at the Federal University of Rio de Janeiro in Brazil, 583
Franzotti Sant’Anna et al
584
Fig 1. Pretreatment facial and intraoral photographs.
with an anterior open bite and symptoms of temporomandibular disorders; she reported occasional pain in the temporomandibular joints (TMJ) during mastication. During the TMJ clinical examination, bilateral crepitation and pain upon masseter muscle palpation were observed. There was history of a pacifier sucking habit until the age of 7 years. At initial orthodontic appointment, she did not report any medical intercurrence, and she was not taking any medication. However, 1 year later, she underwent medical treatment for a nutritional deficiency. She weighed 43 kg and was 1.61 m tall. Initial facial analysis indicated vertical growth with mild facial asymmetry toward the right side, a convex profile, increased lower facial third, and the absence of passive lip sealing with increased mentalis muscle activity with closed lips (Fig 1). As for the functional aspects, there was improper tongue posture with atypical speech and swallowing. The intraoral clinical
March 2017 Vol 151 Issue 3
examination and analysis of the initial cast models showed an Angle Class II Division 1 malocclusion, maxillary and mandibular anterior crowding (9 mm), V-shaped maxillary and quadratic mandibular dental arches, overjet of 9 mm, and anterior open bite of 5 mm. The maxillary and mandibular dental midlines were deviated 0.5 mm to the left and 2 mm to the right from the facial midline, respectively (Figs 1 and 2; see Video 1, available at www.ajodo.org). The pretreatment panoramic radiograph showed narrow and asymmetric condyles (the left condyle was larger than the right condyle) and the presence of all 4 unerupted third molars (Fig 3). Additionally, by analyzing the cone-beam computed tomography (CBCT) images, we observed that the mandibular dental midline deviation might have been influenced by the asymmetric growth of the condyles and the mandible. Cephalometric analysis indicated a Class II skeletal relationship due to mandibular retrusion (ANB, 8.0 ; SNB, 73.9 ), vertical
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
585
Fig 2. A, Pretreatment digital 3D dental casts; B, plaster dental casts set up for the surgical planning.
Fig 3. Pretreatment panoramic radiograph. Note the reduced volume and dimension of the right condyle.
facial growth pattern (y-axis, 66.2 ) with a steep mandibular plane angle (GoGn.SN, 43.8 ; FMA, 39.8 ), and projected and protruded maxillary and mandibular incisors (Fig 4, Table). TREATMENT OBJECTIVES
Based on the diagnostic records, the treatment objectives were as follows: (1) establish a functional occlusion by normalizing overjet and overbite relationships, (2) improve the facial profile, (3) solve the crowding in both arches, (4) coordinate the maxillary and mandibular arches, (5) reduce the lower facial third height, and (6) obtain passive lip sealing and proper tongue posture. TREATMENT ALTERNATIVES
The combined approach of orthodontic treatment and bimaxillary orthognathic surgery (involving
maxillary posterior impaction and mandibular counterclockwise rotation and advancement) with extraction of all third molars and first premolars was first considered because of the effectiveness and predictability of this treatment modality to reduce skeletal open bites. However, this alternative was discarded by the patient, and her parents refused to have their daughter undergo any surgical procedure. The second alternative was a dentoalveolar camouflage treatment with an orthodontic fixed appliance, with extraction of all third molars and first premolars and the use of mini-implants to provide anchorage to intrude the posterior teeth in both arches. After carefully considering that molar intrusion with a likely counterclockwise rotation of the mandible could result in a desirable effect for the patient's facial profile, the second alternative was chosen. The patient and parents were repeatedly advised that the first option was
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
586
Fig 4. A, Pretreatment cephalometric x-ray; B, pretreatment cephalometric tracing. Black, blue, and green lines indicate Steiner, Tweed, and Downs analyses respectively. Table. Pretreatment and posttreatment cephalo-
metric measurements 23-month Pretreatment Posttreatment follow-up SNA angle ( ) 81.9 82.2 81.5 SNB angle ( ) 73.9 74.1 73.5 8.0 8.2 8.0 ANB angle ( ) SND angle ( ) 71.1 71.5 71.4 1:NA (mm) 16.9 1.4 1.8 1:NA ( ) 28.7 11.1 11.4 1:NB (mm) 16.2 16.8 16.5 1:NB ( ) 25.2 28.4 29.6 Pog:NB (mm) 0.1 11.2 11.3 IMPA ( ) 84.3 90.1 90.5 FMA ( ) 39.8 38.4 39.7 1:1 ( ) 118.1 132.3 131.0 Ocl:SN ( ) 12.9 29.2 28.6 43.8 41.1 41.8 GoGn:SN ( ) Upper lip to S line (mm) 13.0 1.5 1.7 Lower lip to S line (mm) 14.1 11.5 11.2 Y-axis ( ) 66.2 65.7 66.4
superior in terms of esthetic and functional outcomes, as well as the lack of predictability of the dentoalveolar camouflage. TREATMENT PROGRESS
Before the orthodontic treatment, all third molars were extracted. A standard 0.022-in edgewise appliance (Morelli, S~ao Paulo, Brazil) was banded and bonded to
March 2017 Vol 151 Issue 3
the maxillary and mandibular second premolars and the first and second molars. Habit spurs were bonded to the lingual surfaces of the maxillary and mandibular incisors to control tongue thrust. Six mini-implants (diameter, 1.4 mm; length, 6 mm; S.I.N. Implants System, S~ao Paulo, Brazil) were placed into the buccal and palatal alveolar bone between the maxillary second premolars and first molars and into the buccal alveolar bone between the mandibular second premolars and first molars on both sides. Sectional archwires of 0.017 3 0.025-in beta-titanium alloy and 0.018 3 0.025-in stainless steel were placed in the maxillary and mandibular arches, respectively, and intrusion of the posterior teeth started with elastomeric chains (100 gf). Then, after the extraction of the maxillary and mandibular first premolars, a 0.022-in edgewise appliance (Morelli, S~ao Paulo, Brazil) was bonded to the maxillary and mandibular anterior teeth, and leveling was started with a sequence of 0.012-in and 0.014-in nickel-titanium, and 0.016-in and 0.018-in continuous stainless steel archwires for the maxillary arch, while intrusive mechanics were continuously applied (Fig 5). A segmented 0.012-in nickel-titanium archwire was used to align the mandibular incisors, and then a 0.014-in stainless steel continuous archwire with loops was inserted to start leveling and aligning. Subsequently, a sequence of continuous 0.014-in, 0.016-in, and 0.018-in stainless steel archwires aligned and leveled the lower arch. Lower archwires were transversely contracted to counteract the expansion tendency caused
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
587
Fig 5. Full fixed edgewise appliance for alignment and leveling procedure.
Fig 6. The 0.018 3 0.025-in stainless steel sectional loop archwires for mandibular molar intrusion.
by the force exerted by the elastics attached to the buccal mini-implants. After 19 months of treatment, leveling of the anterior teeth and crowding resolution were achieved. Then, 2 additional bracket-head mini-implants (diameter, 1.4 mm; length, 8 mm; Sistema INP, S~ao Paulo, Brazil) were placed into the buccal alveolar bone between mandibular canine and second premolars, bilaterally, due to mini-implants failure in the previous sites. Then, 0.018 3 0.025-in stainless steel sectional
archwires with activated coil springs were used for molar intrusion (Fig 6). Because of the inability of the mini-implants to remain stable until the end of the intrusion mechanics, and after several and sequential loosening episodes, a conventional strategy of therapy with a high-pull headgear was implemented (Fig 7). To correct the transverse arch dimension discrepancy that settled in during treatment, a hyrax device was installed in the maxilla and activated 0.75 mm on the first day and 0.25 mm once a week for 14 weeks
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
588
Fig 7. A, High-pull headgear; B, hyrax appliance.
Fig 8. Intraoral photographs. The white arrows indicate the gingival hyperplasia surrounding the miniimplant during a loosening episode. Note that the only mini-implant that remained stable was the one between the mandibular left second premolar and first molar. From this moment on, conventional orthodontic therapy was adopted. An indirect mini-implant anchorage procedure was used to correct the mandibular midline.
Fig 9. Sliding jigs and Class II intermaxillary elastics. The elastics were attached to the mandibular second molars to increase the horizontal force vector.
(Fig 7). The transverse dimension control was performed gradually with progressive coordination of maxillary and mandibular archwires and elimination of premature contacts that contributed to the bite
March 2017 Vol 151 Issue 3
closure. The molars palatal cusps were also flattened with an oval diamond bur used at high speed to minimize occlusal interference. During the expansion, the high-pull headgear usage was not discontinued, and
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
589
Fig 10. Posttreatment facial and intraoral photographs.
the rigid frame of the hyrax prevented buccal tipping of maxillary molars. The inferior dental midline was corrected to the left by managing the residual extraction spaces. All mandibular mini-implants were lost with the exception of the one between the mandibular left second premolar and first molar, which was maintained to assist with the mandibular midline correction (Fig 8; see Video 2, available at www.ajodo.org). To control the tongue posture during treatment, the patient was instructed to maintain her tongue against the hard palate when swallowing and resting. The orthodontic finalization stage proceeded with a 0.019 3 0.025-in stainless steel archwire with lingual root torque compensations in the maxillary incisor region. Bilateral sliding jigs associated with Class II intermaxillary elastics were installed to
improve posterior intercuspation (Fig 9). The mechanical device with sliding jigs was installed to favor horizontal force direction with a decrease of posterior extrusive forces induced by Class II elastics. Front cross elastics (1/400 heavy) were used from the maxillary left canine to the mandibular right canine to improve the dental midlines and transverse interarch coordination. After fixed appliances removal, alginate impressions were poured to obtain models of the maxillary and mandibular arches. Essix retainers were thermoformed from 1 mm sheets (Dentsply, S~ao Paulo, Brazil) and cosmetic restorations. TREATMENT RESULTS
Posttreatment photographs and dental 3dimensional (3D) casts demonstrate the achievement
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
590
Fig 11. Posttreatment digital 3D dental casts.
Fig 12. Posttreatment panoramic radiograph.
of Class I molar and canine relationships, crowding resolution, harmonious dental arches, and dental midlines coinciding with the facial midline (Figs 10 and 11; see Video 3, available at www.ajodo.org). The panoramic evaluation showed minimal root resorption of the maxillary incisor apex and ideal root parallelism (Fig 12). The cephalometric outcomes indicate a slight counterclockwise rotation of the mandible, expressed by the decrease of the GoGn.SN angle from 43.8 to 41.1 at the final records (Fig 13).
March 2017 Vol 151 Issue 3
The facial profile was improved, and the mentalis muscle became less stressed at rest (Figs 14 and 15). An improper tongue posture habit was discontinued, and the patient's TMJs were asymptomatic for 23 months, although with persistent crepitation. The CBCT analysis of the region indicated a condyle aspect similar to that observed at the initial examination (Fig 16). Furthermore, the vertical and horizontal relationships of the incisors were successfully corrected and remained stabled over the 23-month follow-up period
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
591
Fig 13. A, Posttreatment cephalometric radiograph extracted from the CBCT; B, cephalometric tracing. Black, blue, and green lines indicate Steiner, Tweed, and Downs analyses respectively.
(Figs 17-19). The follow-up records (Fig 20) demonstrate that the periodontal health status was maintained as both teeth and bone tissue were properly preserved. Tracing superimpositions showed a decrease in lower facial height due to the intrusion of posterior teeth and counterclockwise rotation of the mandible (Figs 21 and 22), as well as significant maxillary incisor leveling, since they were in infraocclusion. DISCUSSION
Since skeletal open-bite malocclusions are frequently characterized by overeruption of posterior teeth, vertical control of dentoalveolar height during orthodontic treatment becomes a critical step.2 It is not questioned whether skeletal anchorage systems, especially miniimplants, enable the nonsurgical treatment of more severe cases.4,14,15 Mini-implant failure rate is approximately 13.5%16; in other words, the probability of an orthodontic mini-implant loosening is less than 1 in 5.17 This is a particular point to be noted because this case report dealt with recurrent mini-implant failure episodes and the impossibility of using other skeletal anchorage systems, such as miniplates or even orthognathic surgery, once the patient and her parents refused to invasive procedures. In addition, the patient systemic health condition presented another limitation to these alternative procedures. Faced with limited available treatment options, we decided to use the classical high-pull headgear associated with the hyrax dentoalveolar expander. The highpull strategy was considered because of the possibility
of intrusion, or at least to avoid extrusion, of the maxillary molars, with a possible counterclockwise mandibular rotation.18 The hyrax expander was used for maxillary transverse dimension correction. The posterior crossbite that was settled in during the treatment was, in part, related to the mini-implant mechanics of the inferior lower arch that caused some expansion, even with the contraction of all mandibular archwires during this phase of treatment. Furthermore, the maxillary arch had a transverse constriction that could be better visualized when the initial casts were manipulated to simulate the correction of the sagittal discrepancy. Slow maxillary expansion is recommended for adults with a transverse maxillary deficiency; yet it still involves risks such as relapse, pain, swelling, gingival recession, bone loss, and root resorption.19 By limiting our activation to 0.25 mm per week and anchoring the modified hyrax expander to 3 teeth on each side, we minimized these side effects. We controlled the natural tendency of the posterior dentition toward buccal crown inclination, which might lead to occlusal interference as the molars' palatal cusps are extruded. This controlled expansion along with the high-pull headgear curbed the vertical forces that could lead to clockwise rotation of the mandible and subsequent opening of the anterior bite that was previously reported by Sant’Anna et al.19 Justification for the use of CBCT images as a complementary examination procedure was provided by the information regarding the TMJ evaluation,20 accurate lateral cephalometry, frontal and panoramic
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
592
Fig 14. CBCT superimpositions: A, 3D translucent cranial base superimposition at the phase initial (green) and at posttreatment (yellow); B, axial slice of the maxillary arch, made on the 3D cranial base superimposition; C, midsagittal slice of the same superimposition; D, translucent soft tissue initial (white) and posttreatment (red) superimposition.
Fig 15. Profile comparisons: A, pretreatment; B, posttreatment; C, follow-up.
March 2017 Vol 151 Issue 3
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
593
Fig 16. CBCT sagittal and coronal 2-dimensional projections of the TMJs: A, pretreatment; B, posttreatment; C, follow-up. Note that the condyle asymmetry remained similar between these periods.
Fig 17. CBCT midsagittal slices: A, pretreatment; B, intermediate; C, posttreatment; D, follow-up. The lingual root torque of the maxillary incisors, observed from the intermediate to posttreatment and followup slices, allowed the counterclockwise movement of the chin.
2-dimensional projections,21 and orthognathic surgical planning.22 In addition to the preexisting TMJ dysfunction, the patient had other predisposing factors for condylar resorption: high mandibular plane angle; small condyles on long, slender condylar necks; and a female gender in the age range of 15 to 35 years.23,24 Since the orthodontic and orthopedic forces used during treatment could trigger alterations in condyle shape that could worsen her open bite, a careful TMJ
follow-up was performed.25 No evident alterations in condyles shape and volume were noticed in the TMJ projections images obtained from the CBCTs (Fig 16). Extraction of the 4 first premolars was essential to correct the full Angle Class II molar and canine relationships, change arch format, eliminate crowding in both arches, and correct the midline deviation and sagittal repositioning of the maxillary incisors. Improper tongue posture was an additional etiologic
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
594
Fig 18. Follow-up facial and intraoral photographs.
component of the malocclusion; therefore, spurs and speech therapy were implemented to reprogram the patient's neurologic consciousness of an adequate tongue rest position during treatment and the retention period.26 Our outcomes demonstrated that the objectives proposed were satisfactorily achieved because of the association of the treatment procedures and also the patient's excellent cooperation with the extraoral device. The cephalometric superimpositions (Fig 22) showed that more relevant changes were observed in the maxillary arch, which showed both molar intrusion and incisor extrusion. The occlusal plane became progressively steeper (Ocl:SN angle increased from 12.9 to 29.2 at the final records and to 28.6 at the follow-up records) as horizontal and vertical incisor overlaps were obtained. There was a moderate decrease of the mandibular plane
March 2017 Vol 151 Issue 3
angle (expressed by the GoGnSN angle reduction from 43.8 to 41 and retained at 41.8 ) that contributed to the anterior open-bite closure and the lower facial height reduction. This is supported by the fact that a small posterior intrusion (1 mm) can produce 3 to 4 mm of forward and upward movement of the chin.27 Although the mean relapse rate of molar intrusion mechanics is 22.8%,4 previous studies have reported that it did not influence the posttreatment skeletal and dental outcomes because of the maxillary incisors’ passive eruption as a compensatory mechanism.4,13 For further information regarding this aspect, we monitored the patient on a monthly basis for 23 months. The data indicated that the outcomes concerning the occlusion, condyle aspect, tongue posture habit, and periodontal status were stable over this period. Posterior intrusion was obtained
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
595
Fig 19. Follow-up digital 3D dental casts.
Fig 20. Follow-up panoramic radiograph.
with a combination of the mini-implant mechanics in the leveling phase and excellent use of the high-pull headgear. Although we have no medical evidence, we speculate that the nutritional deficiency, reflected in the poor quality of the bone (high porosity) observed during the insertion of the mini-implants, favored the molar intrusion movement because of reduced resistance. The upper lip was retracted 4.5 mm after the maxillary incisor retraction of 8.3 mm. Despite this amount of retraction, the analysis of the upper airway showed no important differences between either the initial and final volumes, or the initial and final minimal axial areas.28 Actually, the latter measurement, considering the most
important respiratory issues, had a slight increase from 89.7 to 101.9 mm2.29 These numbers should be read with care because airway measurements at different times, even for the same patient, are highly variable and can be influenced by breathing stage and head posture.30,31 It took us a great deal of time to progressively correct the inferior dental midline using the premolar space on the left side. This phase was the most time-consuming and difficult part of the treatment. After correcting the dental midline and adjusting the teeth to their correct positions (torque, leveling, distalization, and so on), the bite closed. No elastics were used to close the bite. Furthermore, we had intrusion of the posterior teeth (with mini-implants and high-pull headgear). Most of
American Journal of Orthodontics and Dentofacial Orthopedics
March 2017 Vol 151 Issue 3
Franzotti Sant’Anna et al
596
Fig 21. A, Follow-up cephalometric radiograph extracted from CBCT; B, cephalometric tracing. Black, blue, and green lines indicate Steiner, Tweed, and Downs analyses respectively.
Fig 22. Superimposition of cephalometric tracings of pretreatment (black line), posttreatment (red line), and follow-up (green line) phases: A, superimposed on the sella-nasion plane at sella; B, superimposed on the palatal and mandibular planes.
the incisor extrusion was basically vertical during aligning and retraction because those teeth were in infraocclusion and proclined. Regarding the esthetic outcomes, the camouflage of a severe Class II open-bite malocclusion, with a hyperdivergent growth pattern, is a treatment with esthetic limitations when compared with the more beneficial surgical impacts on the facial profile and the patient's smile. However, this patient's esthetics were not
March 2017 Vol 151 Issue 3
compromised (gummy smile) by leveling the maxillary incisors, since they were in infraocclusion. In addition to this, there was an improvement in the perioral muscle balance expressed by significant attenuation of the mentalis strain (Fig 15). The several advantages of skeletal anchorage for the mini-implant based system justify the broadening of its application in orthodontic treatments. However, until all factors influencing mini-implant loosening are identified
American Journal of Orthodontics and Dentofacial Orthopedics
Franzotti Sant’Anna et al
and resolved, an alternative treatment option—in this case, extraoral and intraoral devices—should be at hand to achieve predictable and satisfactory treatment results.
597
14.
CONCLUSIONS
A severe high-angle skeletal Class II open-bite malocclusion was successfully treated with a nonsurgical conservative approach, using mini-implant skeletal anchorage followed by a conventional extraoral appliance and extraction of the first premolars. After miniimplants failure, the effective use of high-pull headgear associated with a hyrax appliance for molar intrusion and simultaneous incisor retraction provided a successful functional and esthetic improvement, as shown in the outcomes. SUPPLEMENTARY DATA
15.
16.
17. 18. 19. 20.
Supplementary data related to this article can be found online at http://dx.doi.org/10.1016/j.ajodo. 2016.01.020. 21. REFERENCES 1. Reichert I, Figel P, Winchester L. Orthodontic treatment of anterior open bite: a review article—is surgery always necessary? Oral Maxillofac Surg 2014;16:271-7. 2. Subtelny JD, Sakuda M. Open-bite: diagnosis and treatment. Am J Orthod 1964;50:337-58. 3. Greenlee GM, Huang GJ, Chen SS, Chen J, Koepsell T, Hujoel P. Stability of treatment for anterior open-bite malocclusion: a meta-analysis. Am J Orthod Dentofacial Orthop 2011;139:154-69. 4. Baek MS, Choi YJ, Yu HS, Lee KJ, Kwak J, Park YC. Long-term stability of anterior open-bite treatment by intrusion of maxillary posterior teeth. Am J Orthod Dentofacial Orthop 2010;138: 396.e1-9: discussion 396-8. 5. Huang GJ, Justus R, Kennedy DB, Kokich VG. Stability of anterior openbite treated with crib therapy. Angle Orthod 1990;60:17-24. 6. Kuster R, Ingervall B. The effect of treatment of skeletal open bite with two types of bite-blocks. Eur J Orthod 1992;14:489-99. 7. Kim YH. Anterior openbite and its treatment with multiloop edgewise archwire. Angle Orthod 1987;57:290-321. 8. Proffit WR, Bailey LJ, Phillips C, Turvey TA. Long-term stability of surgical open-bite correction by Le Fort I osteotomy. Angle Orthod 2000;70:112-7. 9. Buschang BH, Sankey W, English JP. Early Treatment of hyperdivergent open-bite malocclusions. Semin Orthod 2002;8:130-40. 10. Umemori M, Sugawara J, Mitani H, Nagasaka H, Kawamura H. Skeletal anchorage system for open-bite correction. Am J Orthod Dentofacial Orthop 1999;115:166-74. 11. Glenn G. An American Board of Orthodontics case report: the orthodontic-surgical correction of a Class II malocclusion with anterior open bite. Am J Orthod Dentofacial Orthop 1996;110:81-7. 12. Sherwood KH, Burch JG, Thompson WJ. Closing anterior open bites by intruding molars with titanium miniplate anchorage. Am J Orthod Dentofacial Orthop 2002;122:593-600. 13. Sugawara J, Baik UB, Umemori M, Takahashi I, Nagasaka H, Kawamura H, et al. Treatment and posttreatment dentoalveolar changes following intrusion of mandibular molars with applica-
22.
23.
24.
25.
26.
27. 28.
29.
30.
31.
American Journal of Orthodontics and Dentofacial Orthopedics
tion of a skeletal anchorage system (SAS) for open bite correction. Int J Adult Orthodon Orthognath Surg 2002;17:243-53. Heravi F, Bayani S, Madani AS, Radvar M, Anbiaee N. Intrusion of supra-erupted molars using miniscrews: clinical success and root resorption. Am J Orthod Dentofacial Orthop 2011;139(Suppl 4): S170-5. Deguchi T, Kurosaka H, Oikawa H, Kuroda S, Takahashi I, Yamashiro T, et al. Comparison of orthodontic treatment outcomes in adults with skeletal open bite between conventional edgewise treatment and implant-anchored orthodontics. Am J Orthod Dentofacial Orthop 2011;139(Suppl 4):S60-8. Papageorgiou SN, Zogakis IP, Papadopoulos MA. Failure rates and associated risk factors of orthodontic miniscrew implants: a metaanalysis. Am J Orthod Dentofacial Orthop 2012;142:577-95.e7. Stanford N. Mini-screws success rates sufficient for orthodontic treatment. Evid Based Dent 2011;12:19. Brown P. A cephalometric evaluation of high-pull molar headgear and face-bow neck strap therapy. Am J Orthod 1978;74:621-32. Sant'Anna EF, Marquezan M, Sant'Anna CF. Retreatment of an adult skeletal Class II patient. J Clin Orthod 2013;47:545-52. Librizzi ZT, Tadinada AS, Valiyaparambil JV, Lurie AG, Mallya SM. Cone-beam computed tomography to detect erosions of the temporomandibular joint: effect of field of view and voxel size on diagnostic efficacy and effective dose. Am J Orthod Dentofacial Orthop 2011;140:e25-30. Farman AG, Scarfe WC. Development of imaging selection criteria and procedures should precede cephalometric assessment with cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2006;130:257-65. Kapila S, Conley RS, Harrell WE Jr. The current status of cone beam computed tomography imaging in orthodontics. Dentomaxillofac Radiol 2011;40:24-34. Moore KE, Gooris PJ, Stoelinga PJ. The contributing role of condylar resorption to skeletal relapse following mandibular advancement surgery: report of five cases. J Oral Maxillofac Surg 1991;49:448-60. Kerstens HC, Tuinzing DB, Golding RP, van der Kwast WA. Condylar atrophy and osteoarthrosis after bimaxillary surgery. Oral Surg Oral Med Oral Pathol 1990;69:274-80. Peltola JS, Nystrom M, Kononen M, Wolf J. Radiographic structural findings in the mandibular condyles of young individuals receiving orthodontic treatment. Acta Odontol Scand 1995;53: 85-91. Bosio JA, Justus R. Treatment and retreatment of a patient with a severe anterior open bite. Am J Orthod Dentofacial Orthop 2013; 144:594-606. Kuhn RJ. Control of anterior vertical dimension and proper selection of extraoral anchorage. Angle Orthod 1968;38:340-9. Stefanovic N, El H, Chenin DL, Glisic B, Palomo JM. Three-dimensional pharyngeal airway changes in orthodontic patients treated with and without extractions. Orthod Craniofac Res 2013;16: 87-96. Vos W, De Backer J, Devolder A, Vanderveken O, Verhulst S, Salgado R, et al. Correlation between severity of sleep apnea and upper airway morphology based on advanced anatomical and functional imaging. J Biomech 2007;40:2207-13. El H, Palomo JM. Measuring the airway in 3 dimensions: a reliability and accuracy study. Am J Orthod Dentofacial Orthop 2010;137(Suppl 4):S50.e1-9: discussion S50-2. Mattos CT, Cruz CV, da Matta TC, Pereira Lde A, Solon-de-Mello Pde A, Ruellas AC, et al. Reliability of upper airway linear, area, and volumetric measurements in cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2014;145:188-97.
March 2017 Vol 151 Issue 3