Changes In Mandibular Condyle Positions Before And After Bilateral Sagittal Split Ramus Osteotomy For Mandibular Prognsthism

Mandibular prognathism (MP) or skeletal Class Ⅲ malocclusion with aprognathic mandible is one of the most severe maxillofacial deformities. Thefacial deformity not only hamper the stomatognathic function, but alsoinfluence the aesthetic. Therefore, effecting the mental health. Orthognathicsurgery in conjunction with orthodontic treatment is required for the correctionof adult MP,whose ANB angle <4°。Orthognathic surgery is performed toimprove facial esthetics, function, and dental–occlusal relationships.Stability ofTMJ is an important goal for every surgeon. We measures the joint spaces，preand post BSSRO to correct skeletal Class Ⅲ malocclusion. Our study aims atevaluating，and analyzing the stability of the condylar position，the alleviation ofTMJ symptom before and after BSSRO. We hope our study may provide someuseful information for clinical treatment of the Class Ⅲ malocclusion.Objective: Study of whether condylar position changes before and afterorthodontics and surgical treatment.We wonder that additional TMJ can be caused by Bilateral sagittal split ramus osteotomy（BSSRO）for correctingskeletal Class Ⅲ.Methods：sixteen patients with mandibular prognathism were selected. Thepatients have been treated by orthodontics and bilateral sagittal split ramusosteotomy（BSSRO）. We measured both sides of the anterior，upper and posternspaces respectively in two weeks before the operation and for six months. Thedata was analyzed by SPSS16.0software package for paired t test.The prevalence and the results on pain, sounds, clicking, joint locking,limited mouth opening, and tenseness were evaluated TMJ disorders changesbefore and after orthognathic surgery.Results：16patients have recovered the oral function and facialappearance after treatment. The study showed that before the operation the meananterior, posterior and upper spaces were1.91±0.28mm，2.30±0.35mm and2.51±0.41mm on the left side, mean anterior, posterior and upper spaces were2.14±0.58mm、2.64±0.59mm、2.92±0.38mm on the right side. After theoperation，mean anterior,posterior and upper spaces were1.98±0.36mm、2.39±0.39mm、2.62±0.37mm on the left side, mean anterior, posterior and upperspace were2.14±0.75mm、2.67±0.81mm、2.60±0.59mm on the right side. Therewas no statistical significant difference about three spaces pre and post operationon BSSRO（P>0.05）.TMJ symptoms were not significantly changed after treatment for patientswith pre-operative symptoms. Most of patients were very satisfied with theresults.Conclusion：The results suggest that TMJ and condyle were no change bycombined orthodontic and BSSRO.