Introduction
Skeletal Class II malocclusion with mandibular deficiency is one of the most common problems that patients seek treatment.1 Class II malocclusion in India varies from 1.9% to 8.37%.2 Orthognathic surgery is a good treatment approach for patients with severe skeletal discrepancies beyond the reach of conventional orthodontic treatment to obtain a more harmonious facial, skeletal and soft tissue relationship as well as to improve occlusal function. Patients undergoing orthognathic surgery may experience psychosocial benefits and improve their self-confidence, facial image and social adaptation.3 This article which illustrates two case reports, shows the benefit of a team approach in correcting a Class II skeletal deformity by Bilateral sagittal split osteotomy (BSSO) with mandibular advancement.
Case Reports
Case 1
Diagnosis and etiology
A 24-year-old male patient, had a chief complaint of forwardly placed upper front teeth. Facial photographs showed a symmetric face, convex profile with a retruded chin, a proportionally short lower anterior facial height, potentially competent lip at rest, and a deep labiomental fold. He had a normal gingival tissue display when smiling. [Figure 1]
Intraorally, he had Angle’s Class II div 1 with a 7 mm overjet and a 4 mm overbite, mild crowding, dental midline matching. [Figure 2]
On cephalometric analysis the patient had class II skeletal pattern (ANB = 6°) with retruded mandible (SNB=77°), horizontal growth pattern (FMA= 22°) and bidental proclination. [Table 1, Figure 3)
Table 1
Cephalometric analysis of case 1
Treatment progress
Pre-surgical phase
Maxillary and mandibular arches were banded and bonded with 0.022″ slot preadjusted MBT(McLaughlin, Bennett, and Trevisi) bracket prescription. Treatment progressed from levelling and alignment with 0.016″ NiTi, 0.018″SS, 0.019″ × 0.025″ NiTi, 0.021″ × 0.025″ NiTi and 0.021″ × 0.025″ stainless steel wires. Presurgical records were taken, models were mounted using facebow transfer, mock surgery was done, and a surgical splint was fabricated.[Figure 4, Figure 5]
Surgical treatment
BSSO (Bilateral Sagittal split osteotomy) with 7mm of mandibular advancement was performed by an oral surgeon under general anesthesia. The osteotomy cuts were secured with titanium plates, surgical splint was placed in patient mouth and intermaxillary fixation was done for a period of 14 days.
Case 2
Diagnosis and Etiology
A 24-year-old male patient, had a chief complaint of forwardly placed upper front teeth. Facial photographs showed a symmetric face, convex profile with a retruded chin, a proportionally short lower anterior facial height, potentially competent lip at rest, and a deep labiomental fold. He had a normal gingival tissue display when smiling. [Figure 8]
Intraorally, he had Angle’s Class II Division 1 subdivision (right) malocclusion with proclined upper incisors, bidental crowding, increased overjet and deep overbite. [Figure 9]
On cephalometric analysis the patient had class II skeletal pattern (ANB = 8°) with retruded mandible (SNB=76°), horizontal growth pattern (FMA= 22°) and bidental proclination. [Table 2, Figure 10]
Table 2
Cephalometric analysis of case 2
Treatment plan
Surgical line of treatment with extraction of maxillary second premolars and mandibular first premolars followed by mandibular advancement BSSO surgery.
Treatment Progress
Maxillary and mandibular arches were banded and bonded with 0.022″ slot preadjusted MBT(McLaughlin, Bennett, and Trevisi) bracket prescription Treatment progressed from levelling and alignment with 0.016″ NiTi, 0.018″SS, 0.019″ × 0.025″ NiTi and 0.019″ × 0.025″ stainless steel wires. Presurgical records were taken, models were mounted using facebow transfer, mock surgery was done, and a surgical splint was fabricated. [Figure 11] BSSO (Bilateral Sagittal split osteotomy) with 5mm mandibular advancement was performed. Finishing and detailing was done for 5 months, and debonding was done after achieving the treatment goals. An upper and lower fixed bonded lingual retainer were given. [Figure 12, Figure 13]
Treatment Results
In both the cases, the appraisal of the treatment outcomes showed a well aligned dentition where extra-orally, they demonstrated a pleasant smile and well-balanced facial profile and competent lips. Cephalometric evaluation [Figure 14a,b] and superimpositions [Figure 15a,b] confirmed an exemplary change in the profile and the case was finished in the Class I skeletal base. The intraoral photographs revealed a Class I molar, Class I canine and Class I incisor relationship on both the sides. Ideal and appropriate overjet and the overbite was achieved post-treatment. Total duration of time taken in both the cases were approximately 24 months.
Discussion
The treatment of severe dentofacial deformities in adult patients is a challenging task for both orthodontist and oral surgeon because of the skeletal and facial disharmony, absence of jaw growth and a tendency to relapse. Camouflage treatment with skeletal discrepancy will be initiated with greater facial imbalance and this imbalance will either be maintained or deteriorated in value in relation to point A, the upper incisor and the lower lip.4 BSSO with advancements of up to 7 mm in patients with a low or normal MP-angle are considered stable with minimal long-term post-surgical skeletal relapse. 5 Similarly in our cases, we opted for mandibular advancement not more than 7mm. Studies suggest that with mandibular advancement surgery, profiles of patients were observed to improve with a decrease in facial convexity, an increase in lower facial height, decrease depth of the mentolabial sulcus. In addition, lip competency will be improved, which is agreeable with results of our cases.6
During the pre-surgical orthodontic treatment, the opposite of camouflage treatment is performed dentally where decompensation is achieved by moving teeth to a proper functional position relative to the skeletal bases.7 During this phase of treatment, generally, the goal is to eliminate the dental interferences for the ideal correction of existing skeletal discrepancies.8 In our first case, decompensation was performed with non-extraction protocol whereas in the second case, decompensation was done by extraction of premolars due to presence of moderate crowding in arches
Conclusion
A skeletal Class II malocclusion treated with proper diagnosis and treatment planning improves the esthetic value of the patient. Inter-disciplinary approach favoured in the successful management of a patient with mandibular advancement (BSSO) to achieve superior function, stability, facial esthetics, an ideal occlusion and also provided good postoperative stability.
