title: Biomechanical Effects of Masticatory Muscles on Human Mandible After Reconstructed Mandibulectomy Tumor.
abstract: BACKGROUND
  This study aimed to analyze and compare the stress distribution on the condylar process. This study was also designed to determine the effect of closing and opening muscle groups of the jaw on mandibular stability after mandibular tumor osteotomy reconstruction by three-dimensional finite element analysis.
  
  
  METHODS
  Three-dimensional reconstructed mandibles were used and divided into 2 groups: (1) 6 patients with normal mandible and (2) 6 mandibular tumor patients who underwent osteotomy reconstruction. Computed tomography scans of normal and reconstructed mandibular tumor osteotomy patients were obtained. Three-dimensional models were reconstructed using Simpleware 5.0 software. Boundary constraint and load conditions were applied. The solution process was run, and the actions of closing and opening muscle groups were simulated and calculated using finite element analysis software. Statistical software was used for analysis of the condylar stress distribution.
  
  
  RESULTS
  A significant difference was observed in stress distributions on the anterior condyle of the healthy volunteers and the reconstructed mandibular tumor osteotomy patients, who were subjected to tumor osteotomy surgery in the opening muscle groups (P < 0.05). By contrast, no significant difference was observed in the posterior condyle of the opening muscle group and the closing muscle group (P > 0.05).
  
  
  CONCLUSIONS
  Muscular imbalance in postoperative mandibular tumor reconstruction was changed in patients. We adjusted the force of the mandible closing muscle intraoperatively to achieve muscle balance. Therefore, poor swallowing, failure to retain saliva, speech impairment, and esthetic disfigurement were repaired and/or resolved.
authors: From the *Departments of Orthopedics and †Medical Research, General Hospital of Guangzhou Military Command, Guanggzhou, Guangdong, China.
authors: Limin
authors: L
authors: Ma
authors: Ye
authors: Y
authors: Zhou
authors: Yu
authors: Y
authors: Zhang
authors: Hong
authors: H
authors: Xia
authors: Xia
authors: X
authors: Zhou
authors: Qingshui
authors: Q
authors: Yin
authors: Zilong
authors: Z
authors: Yao