title: Three-dimensional finite-element model of the human temporomandibular joint disc during prolonged clenching.
abstract: In the temporomandibular joint (TMJ), overloading induced by prolonged clenching appears to be important in the cascade of events leading to disc displacement. In this study, the effect of disc displacement on joint stresses during prolonged clenching was studied. For this purpose, finite-element models of the TMJ, with and without disc displacement, were used. Muscle forces were used as a loading condition for stress analysis during a time-period of 10 min. The TMJ disc and connective tissue were characterized as a linear viscoelastic material. In the asymptomatic model, large stresses were found in the central and lateral part of the disc through clenching. In the retrodiscal tissue, stress relaxation occurred during the first 2 min of clenching. In the symptomatic model, large stresses were observed in the posterior part of the disc and in the retrodiscal tissue, and the stress level was kept constant through clenching. This indicates that during prolonged clenching the disc functions well in the asymptomatic joint, meanwhile the retrodiscal tissue in the symptomatic joint is subject to excessive stress. As this structure is less suitable for bearing large stresses, tissue damage may occur. In addition, storage of excessive strain energy might lead to breakage of the tissue.
authors.affiliation: Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Hirose
authors.forename: Eiji
authors.initials: E
authors.lastname: Tanaka
authors.forename: Masao
authors.initials: M
authors.lastname: Tanaka
authors.forename: Reiji
authors.initials: R
authors.lastname: Fujita
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kuroda
authors.forename: Eizo
authors.initials: E
authors.lastname: Yamano
authors.forename: Theo M G J
authors.initials: TM
authors.lastname: van Eijden
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tanne
mesh_terms: D000328:Adult; D001732:Bite Force; D002012:Bruxism / Q000503:physiopathology*; D003799:Dental Stress Analysis; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D004204:Joint Dislocations / Q000209:etiology; D008953:Models, Anatomic; D013314:Stress, Mechanical; D013704:Temporomandibular Joint / Q000503:physiopathology*; D019224:Temporomandibular Joint Disc / Q000293:injuries / Q000503:physiopathology*; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology*