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CASE REPORT Treatment of Skeletal Class III Malocclusion with the Biofunctional System RODRIGO HERMONT CANÇADO, DDS, MSc, PhD KARINA MARIA SALVATORE DE FREITAS, DDS, MSc, PhD FABRÍCIO PINELLI VALARELLI, DDS, MSc, PhD BRUNO DA SILVA VIEIRA, DDS, MSc LENIANA SANTOS NEVES, DDS, MSc, PhD W hen a skeletal Class III malocclusion is diagnosed early enough, the preferred treatment is orthopedic, involving maxillary traction with facemasks—often combined with rapid maxillary expansion—followed by orthodontic correction using Class III elastics.1,2 If the problem is not diagnosed until the permanent dentition, however, the treatment options are limited to com- Dr. Cançado pensatory or surgical-orthodontic therapy.3 Surgical treatment may produce the most esthetic results, but is less commonly performed because of its risks and expense.4 The success of compensatory orthodontic treatment depends on the severity of the anteroposterior discrepancy, the facial and muscular balance, and the influence of heredity on the malocclusion.5-11 Class III patients Dr. Freitas Dr. Valarelli typically present with a dental compensation guided by the facial musculature, which further complicates treatment planning due to the limitations of orthodontic mechanics in the lower arch.5,12,13 This article describes the use of the Biofunctional* appliance system in compensatory *Morelli Ortodontia, Sorocaba, São Paulo, Brazil; www.morelli.com.br. Dr. Vieira Dr. Neves Drs. Cançado, Freitas, and Valarelli are Professors, and Dr. Vieira is an orthodontic graduate student, Department of Orthodontics, Ingá Faculty, Rodovia PR 317, no. 6114, Maringá 87035-510, Paraná, Brazil. Dr. Neves is a Professor, Department of Orthodontics, Federal University of Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil. E-mail Dr. Cançado at [email protected]. VOLUME XLIX NUMBER 11 © 2015 JCO, Inc. 713 Treatment of Skeletal Class III Malocclusion with the Biofunctional System Fig. 1 12-year-old Class III female patient with impacted upper left canine and anterior crossbite before treatment. 714 JCO/NOVEMBER 2015 Cançado, Freitas, Valarelli, Vieira, and Neves TABLE 1 CEPHALOMETRIC ANALYSIS Pre- Post- 26 Months treatment TreatmentPost-Treatment SNA Co-A SNB Co-Gn ANB Wits appraisal FMA (MP-FH) SN-GoGn Occlusal plane-SN Lower facial height (ANS-Me) U1-NA U1-NA U1-PP U6-PT vertical U6-PP UMKC L1-NB L1-NB L6 apex-Symphysis L6 crown-Symphysis L6-PP UMKC Molar relationship Overjet Overbite Nasolabial angle (Col-Sn-UL) Upper lip-S line Lower lip-S line treatment of a skeletal Class III malocclusion. Diagnosis and Treatment Planning A 12-year-old female presented with the chief complaint of an impacted upper left canine and anterior crossbite. Clinical examination showed moderate mandibular protrusion, mild VOLUME XLIX NUMBER 11 81.4°83.5° 82.9° 75.6mm79.4mm 80.2mm 82.6°81.0° 81.8° 100.9mm102.7mm 103.6mm 0.8°3.6° 4.1° −3.3mm +0.5mm +1.9mm 23.7° 26.5° 26.0° 31.3°34.3° 33.6° 15.7° 13.8° 14.2° 57.5mm 58.3mm 59.3mm 32.1°32.7° 32.6° 3.0mm5.4mm 5.0mm 21.6mm21.8mm 22.1mm 19.2mm 20.5mm 20.2mm 14.8mm 16.6mm 17.2mm 33.6°32.2° 32.1° 8.3mm7.8mm 7.8mm 16.4mm 15.7mm 14.9mm 17.3mm 18.7mm 17.6mm 23.5mm 22.4mm 22.5mm −3.9mm −1.3mm −1.5mm −4.1mm2.2mm 2.5mm 1.2mm0.7mm 1.3mm 132.7° 106.8° 107.4° −4.3mm 0.2mm −0.4mm 2.2mm 2.0mm 2.4mm maxillary retrusion, an excessive nasolabial angle, a protrusive lower lip, a retrusive upper lip, and a concave profile (Fig. 1). The patient had a bilateral Class III molar relationship associated with an anterior crossbite in centric occlusion, a 1.5mm discrepancy between the dental midlines, and a mild curve of Spee. The panoramic radiograph confirmed that all permanent teeth were present, including the third molars, but the upper left canine was impacted with a mesial angulation. Cephalometric analysis indicated a moderate discrepancy between the bony bases, a long mandibular arch (Co-Gn), slightly excessive lower facial height, and a counterclockwise rotation of the palatal plane (Table 1). The periapical radiographs revealed normal upper and lower incisor 715 Treatment of Skeletal Class III Malocclusion with the Biofunctional System roots. The upper incisors were protrusive, with a marked labial inclination compensating for the anteroposterior discrepancy between the bony bases; the lower incisors were well positioned. Treatment goals were to reduce the concave profile, improve facial esthetics, and obtain Class I molar and canine relationships after moving the impacted upper left canine into the arch. Although orthognathic surgery could have improved the patient’s esthetic appearance and occlusion, it was not deemed suitable in this case because the skeletal Class III malocclusion was mild (ANB = .8º) and the patient and parents were reluctant to authorize surgery.4,14,15 Due to the lack of crowding in the mandibular arch, extraction treatment could actually have worsened the profile, with retraction of the incisors resulting in accentuated retraction of the upper and lower lips and, consequently, an increased nasolabial angle.16,17 Therefore, we recommended a nonextraction approach involving traction of the impacted canine and compensatory orthodontic treatment with Class III intermaxillary elastics. Considering the extreme labial tipping of the upper incisors and the absence of space for traction of the upper left canine, the use of a Roth-prescription appliance for Class III mechanics and space opening could have worsened the incisor tipping and further compromised facial esthetics; it also would have required significant torque control of the upper incisors. Instead, a Biofunctional prescrip- 716 tion was chosen to simplify the mechanics, especially the torque control. The patient and her parents were advised that a good result would depend on the patient’s compliance with elastic wear. Treatment Progress Leveling and alignment began with .016" round nickel titanium archwires in an .022" × .030" preadjusted Biofunctional appliance. We prescribed ⅛" intermaxillary elastics to be attached from palatal buttons on the upper incisors to Kobayashi hooks on the lower lateral-incisor brackets, crossing anteriorly. The patient was instructed to wear the elastics 24 hours a day, removing them only to eat and play sports. The Biofunctional Class III bracket system applies lingual crown torque on the upper incisors (0°) and buccal crown torque on the lower incisors (10°) to counteract the effects of Class III elastics. In this case, because of the significant dentoalveolar compensation, the upper canine slots were angulated 13°; this would improve the anteroposterior occlusal discrepancy, facilitating protrusion of the upper incisors to increase the maxillary arch length. The lower canine slots were angulated 0° to enhance retrusion of the lower incisors, reducing mandibular arch length and allowing compensatory correction of the skeletal Class III discrepancy.12,18 With excellent patient compliance, the negative overjet was corrected in two months. Leveling and alignment took another six months, progressing to .016" × .022" and .019 × .025" nickel titanium and .019" × .025" stainless steel archwires. A nickel titanium open-coil spring was used for 12 months between the upper lateral left incisor and first premolar for space opening and posterior traction of the impacted canine. Next, 3⁄16" intermaxillary Class III elastics were worn for six months to obtain skeletal Class III dentoalveolar compensation. For the last two months of finishing and detailing, ⅛" intermaxillary elastics were worn with a braided archwire (Fig. 2). Treatment Results After 28 months of treatment, a significant improvement in the patient’s profile could be seen (Fig. 3). Class I molar and ca n i ne r elat ion sh ip s we r e achieved, the overjet and overbite were improved, and the anterior crossbite was corrected. The Class III elastics promoted extrusion and mesial angulation of the upper molars and mild extrusion and distal angulation of the lower molars. This generated a clockwise mandibular rotation that helped alleviate the facial concavity.2,19 The upper incisors displayed protrusion without labial tipping, while the lower incisors showed retrusion with minimal lingual tipping or extrusion (Table 1). There was a marked improvement in the relationship between the bony bases, due to the reduced mandibular protrusion and better positioning of the maxilla relative to the cranial base. The nasolabial angle and JCO/NOVEMBER 2015 Cançado, Freitas, Valarelli, Vieira, and Neves upper-lip protrusion were reduced without altering the lowerlip position. A maxillary wraparound plate and a mandibular 3-3 Bonda-Braid** lingual wire were prescribed for retention. Twenty-six months later, the results remained stable, with no change in apical root morphology evident in the periapical radiographs (Fig. 4). Discussion The anteroposterior position of the upper and lower incisors **Reliance Orthodontics, Inc., Itasca, IL; www.relianceorthodontics.com. has an important relationship to facial harmony and smile esthetics. Although compensatory treatment of a skeletal Class III malocclusion inevitably produces some labial inclination of the upper incisors and lingual inclination of the lower incisors, excessive tipping can easily compromise a pleasant smile, especially in a young patient. Moreover, inordinate labiolingual compensation of the incisors can generate bone dehiscences that may lead to gingival recession.20 According to Lin and Gu, compensatory treatment of skeletal Class III malocclusions produced an average upper-incisor proclination of 6° and protrusion of 3mm relative to SN, along with an average lower-incisor retroclination of 6.6° and retrusion of 2mm relative to the mandibular plane.2 Sperry and colleagues found that the upper incisors were tipped 5° labially and the lower incisors retroclined by 3.5°. 21 Similarly, Troy and colleagues observed that the upper incisors were more labially tipped and compensated, while the lower incisors were more retroclined.22 Sperry and colleagues noted that Class III patients with excessive dental inclinations were about three times more likely than Class I or II patients Fig. 2 After 26 months of treatment, short intermaxillary elastics used with braided archwire for finishing and detailing. VOLUME XLIX NUMBER 11 717 Treatment of Skeletal Class III Malocclusion with the Biofunctional System A A B Fig. 3 A. Patient after 28 months of treatment. B. Superimposition of pre- and post-treatment cephalometric tracings. 718 JCO/NOVEMBER 2015 Cançado, Freitas, Valarelli, Vieira, and Neves A A Fig. 4 A. Patient 26 months after completion of treatment (continued on next page). VOLUME XLIX NUMBER 11 719 Treatment of Skeletal Class III Malocclusion with the Biofunctional System B C Fig. 4 (cont.) B. Superimposition of post-treatment and 26-month-post-treatment cephalometric tracings. C. Superimposition of pretreatment (black), post-treatment (green), and 26-month-post-treatment (red) cephalometric tracings. to exhibit gingival recession after orthodontic treatment.21 Vasconcelos and colleagues also found an association between lingual inclination of the lower incisors and the severity of gingival recession.16 In the case shown here, the periodontal support and protection appeared normal at the end of treatment, based on photographs and periapical radiographs. 720 Conclusion As an alternative for the treatment of skeletal Class III malocclusion, the Biofunctional system can produce a satisfactory and stable occlusion and acceptable facial esthetics without any smile or profile impairment due to excessive dental compensation. REFERENCES 1. Hickham, J.H. and Graziano, F.W.: The effectiveness of orthopedic forces in inhibiting mandibular growth, J. La. Dent. Assoc. 28:10-12, 1970. 2. Lin, J. and Gu, Y.: Preliminary investigation of nonsurgical treatment of severe skeletal Class III malocclusion in the permanent dentition, Angle Orthod. 73:401-410, 2003. 3. Franchi, L.; Baccetti, T.; and Tollaro, I.: Predictive variables for the outcome of early functional treatment of Class III malocclusion, Am. J. Orthod. 112:8086, 1997. JCO/NOVEMBER 2015 Cançado, Freitas, Valarelli, Vieira, and Neves 4. De Lir Ade, L.; Moura, W.L.; Oliveira Ruellas, A.C.; Gomes Souza, M.M.; and Nojima, L.I.: Long-term skeletal and profile stability after surgicalorthodontic treatment of Class II and Class III malocclusion, J. Cranio maxillofac. Surg. 41:296-302, 2013. 5. Gelgör, I.E. and Karaman A.I.: Nonsurgical treatment of Class III malocclusion in adults: Two case reports, J. Orthod. 32:89-97, 2005. 6. Closs, L.Q.; Mundstock, K.S.; Ribeiro, D.S.; Reston, E.G.; and Silva, A.N. 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Sperry, T.P.; Speidel, T.M.; Isaacson, R.J.; and Worms, F.W.: The role of dental compensations in the orthodontic treatment of mandibular prognathism, Angle Orthod. 47:293-299, 1977. 22. Troy, B.A.; Shanker, S.; Fields, H.W.; Vig, K.; and Johnston, W.: Comparison of incisor inclination in patients with Class III malocclusion treated with orthognathic surgery or orthodontic camouflage, Am. J. Orthod. 135:146e1146e9, discussion 146-147, 2009. 721