Evaluation of buccolingual molar inclinations among different vertical facial types.

OBJECTIVE: The aim of this study was to compare the buccolingual inclination of maxillary and mandibular molars in adults with different vertical facial types. METHODS: Cone-beam computed tomography images of 135 adult patients (age, 20-45 years) with skeletal Class I maxillomandibular relationships were assigned to normodivergent (n = 46), hypodivergent (n = 49), and hyperdivergent groups (n = 40) according to linear and angular sella-nasion/gonion-menton measurements. The normodivergent group consisted of 24 females and 22 males, hypodivergent group of 26 females and 23 males, and hyperdivergent group of 24 females and 16 males. Buccolingual inclination of the maxillary and mandibular first and second molars was measured relative to the occlusal plane. One-way analysis of variance was used for intergroup comparison. Gender differences were evaluated using independent t-tests. RESULTS: Buccolingual molar inclinations did not differ significantly between females and males (p > 0.05). There were no statistically significant differences among the buccolingual inclinations of the first and second maxillary and mandibular molars of the groups (p > 0.05). CONCLUSIONS: Buccolingual inclinations of maxillary and mandibular molars are similar in normodivergent, hyperdivergent, and hypodivergent adults with Class I sagittal relationships.

Patient with Severe Skeletal Class II Malocclusion: Double Jaw Surgery with Multipiece Le Fort I.

A 22-year-old woman with severe skeletal Class II malocclusion was referred to our clinic. A clinical examination revealed a convex soft tissue profile and increased teeth and gingiva exposure both while smiling and in the natural rest position. She had Class II molar and canine relationship with increased overjet, moderate crowding in both upper and lower jaws, and proclined upper and lower incisors. Skeletally, she showed transverse maxillary deficiency, maxillary vertical excess, and mandibular retrognathia. We planned orthodontic-orthognathic surgery with multipiece Le Fort I osteotomy and bilateral sagittal split osteotomy (BSSO) to achieve ideal occlusion, stability, and facial esthetics. During orthodontic decompensation to relieve the crowding and to gain an ideal incisor inclination, four bicuspid extractions were performed. Because we used continuous mechanics, at the end of the decompensation period, we cut the maxillary arch wire distal to the lateral incisors into three pieces and waited for 3 months for vertical and transversal dental relapse. During the double jaw surgical procedure, the maxilla expanded and impacted with multisegmented Le Fort I osteotomy and the mandible advanced with BSSO. After the orthodontic and orthognathic surgical treatment, the skeletal and dental imbalance was corrected, and functional occlusion and dental and skeletal Class I relationship were achieved. The treatment results were stable at the 1-year follow-up.

Effect of orthognathic surgery on masticatory performance and muscle activity in skeletal Class III patients.

OBJECTIVE: To evaluate the effect of double jaw orthognathic surgery (OGS) on masticatory performance and electromyographic activity of the masseter and anterior temporal muscles in skeletal Class III patients. METHODS: Individuals were instructed to chew standardized round tablets of silicone impression material. The cumulative weight percentage was calculated using sieve analysis. The bilateral surface electromyographic activity of the muscles was evaluated. Following the orthodontic treatment, a stabilization splint was fabricated. Patients were instructed to wear it full-time until the surgical procedure occurred. Recordings were performed before the splint application (T0), after the splint application (T1), 1 month after the OGS (T2), and 6-8 months after the OGS (T3). RESULTS: Median particle size of the chewed silicone material did not differ from T0 to T1 with the use of an occlusal splint (p > 0.05). However, it decreased from 9.46 to 6.92 cm from T2 to T3. From T0 to T3, a statistically significant decrease was found, following the surgical intervention (p < 0.01). A significant decrease in masticatory muscle activity was also observed during the relaxation test from T0 to T3, at which time it reached the control group value. DISCUSSION: OGS enhanced masticatory function by improving occlusion in individuals with a dentofacial deformity.