title: Effect of clenching on biomechanical response of human mandible and temporomandibular joint to traumatic force analyzed by finite element method.
abstract: OBJECTIVE
  The purpose of the present study was to analyze the effect of clenching on the biomechanical response of human mandible and temporomandibular joint (TMJ) to traumatic force by the finite element (FE) method.
  
  
  METHODS
  FE models of the mandible and the TMJ in resting and clenching positions were prepared. Distribution and magnitude of von Mises stress were analyzed by applying force as a point load in the symphyseal, canine, body and angle regions of the mandible. In addition, strain energy density (SED) at the articular disc and in posterior connective tissue of TMJ was analyzed.
  
  
  RESULTS
  In the resting position, von Mises stress was mainly concentrated at the condylar neck and in the retromolar region of the mandible. In the clenching position, the stress at the condylar neck decreased in all loadings. The stress in the retromolar region similary decreased in the symphyseal, canine and body loading, respectively; however, higher stress was observed in the retromolar region on the loading side in the angle loading. High SED was generated at the articular disc and in posterior connective tissues of TMJ in the resting position. The SED in these tissues decreased in all loadings in the clenching position.
  
  
  CONCLUSIONS
  Clenching generally reduces stress at the condylar neck and in the retromolar region of the mandible, and strain energy at the articular disc and in posterior connective tissue of TMJ by traumatic forces on the mandible; however, clenching induces greater stress in the retromolar region on the loading side by traumatic force to the angle region.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara City, Nara, Japan. murakami@naramed-u.ac.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Murakami
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Sugiura
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kawakami
authors.forename: Yu-Bong
authors.initials: YB
authors.lastname: Kang
authors.forename: Sadami
authors.initials: S
authors.lastname: Tsutsumi
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Kirita
mesh_terms: D001696:Biomechanical Phenomena; D001732:Bite Force; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible / Q000502:physiology*; D008953:Models, Anatomic; D011312:Pressure; D013704:Temporomandibular Joint / Q000502:physiology*