title: The influence of the closing and opening muscle groups of jaw condyle biomechanics after mandible bilateral sagittal split ramus osteotomy.
abstract: OBJECTIVE
  To investigate the influence of the closing and opening muscle groups of the jaw on mandibular stability after mandibular bilateral sagittal split ramus osteotomy (BSSRO).
  
  
  METHODS
  To establish finite element models of four conditions (the normal mandible, preoperative mandibular prognathism, postoperative (BSSRO) mandibular prognathism, and mandibular prognathism following virtual BSSRO), we imported Digital Imaging and Communications in Medicine (DICOM) data into three-dimensional reconstruction software. Finite element analysis software and statistical software were used for analysis of the condylar stress distribution as a function of condylar position during the actions of jaw closing and jaw opening muscle groups.
  
  
  RESULTS
  The stress distribution of the normal mandibular bilateral condyle was statistically different from the normal mandibular condyle, indicating that bilateral structures are asymmetrical. There was a significant difference in stress distributions with condyle position between healthy control patients and patients prior to mandibular prognathism surgery (P<0.05). There was no significant difference in stress distributions between the normal mandible and the mandible following virtual surgery or real mandibular prognathism surgery. Additionally, there was no significant difference at 6 months after mandibular prognathism surgery (P>0.05).
  
  
  CONCLUSIONS
  Bilateral structures of the normal mandible were asymmetrical. After mandibular bilateral sagittal split ramus osteotomy, variation of the force arms of closing and opening muscle groups of the jaw was one of the major factors influencing mandibular stability. Virtual surgery is a promising strategy for preoperative planning to improve surgical success and reduce complications.
authors: Department of Laser and Plastic Surgery, Liu Hua Qiao Hospital, Liu Hua Road 111, Guangzhou 510010, China. qixdcn@yahoo.com.cn
authors: Q I
authors: QI
authors: Xiangdong
authors: M A
authors: MA
authors: Limin
authors: Zhong
authors: Z
authors: Shizhen
mesh_terms: D001696:Biomechanical Phenomena; D017076:Computer-Aided Design; D020342:Finite Element Analysis; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008334:Mandible / Q000601:surgery; D008335:Mandibular Condyle / Q000502:physiology*; D008406:Masseter Muscle / Q000502:physiology; D008410:Masticatory Muscles / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D009334:Neck Muscles / Q000502:physiology; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods*; D011378:Prognathism / Q000503:physiopathology / Q000601:surgery; D011626:Pterygoid Muscles / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D012984:Software; D013314:Stress, Mechanical; D013703:Temporal Muscle / Q000502:physiology; D013704:Temporomandibular Joint / Q000502:physiology; D036542:Tomography, Spiral Computed / Q000379:methods; D014584:User-Computer Interface