title: Change in bite force and electromyographic activity of masticatory muscle in accordance with change of occlusal plane.
abstract: OBJECTIVE
  The purpose of the present study was to evaluate effects of occlusal plane on masticatory function (biting force, masticatory muscle activity, biting efficiency) after bimaxillary orthognathic surgery.
  
  
  METHODS
  The subjects of the present study consisted of a group of 55 adults who had undergone bimaxillary surgery more than 6 months earlier. Lateral cephalographs, bite force, and electromyographic measurements of the anterior temporal [EMG(t)] and masseter muscles [EMG(m)] were recorded before and after bimaxillary surgery. Statistical analyses were performed.
  
  
  RESULTS
  In the increased occlusal plane group, the frequency of decreased EMG(t) was significantly high. The frequency of increased EMG(t) was also significantly high in the decreased occlusal plane group. A negative correlation was found between the postoperative occlusal plane angle and the biting force efficiency change. No significant difference was found between the group that moved from an abnormal to a normal range and the group that moved from a normal to an abnormal range. The occlusal plane change was significantly greater in the decreased EMG(t) group than in the increased EMG(t) group.
  
  
  CONCLUSIONS
  The value of EMG(t) was related to the changes in the occlusal plane, and the biting efficiency was affected by the postoperative occlusal plane angle. However, normalization of the occlusal plane might not play a major role in masticatory function.
authors: Department of Oral and Maxillofacial Surgery, Catholic University of Korea, Seoul, Korea. jupark@catholic.ac.kr
authors: Min-Kyu
authors: MK
authors: Park
authors: Sung-Min
authors: SM
authors: Cho
authors: Kyoung-In
authors: KI
authors: Yun
authors: Je-Uk
authors: JU
authors: Park
mesh_terms: D000328:Adult; D001732:Bite Force; D002508:Cephalometry / Q000379:methods; D015331:Cohort Studies; D003766:Dental Occlusion; D004576:Electromyography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008406:Masseter Muscle / Q000502:physiology; D008410:Masticatory Muscles / Q000502:physiology*; D008437:Maxilla / Q000601:surgery; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D011446:Prospective Studies; D013703:Temporal Muscle / Q000502:physiology