Modeling of the Effect of Friction in the Temporomandibular Joint on Displacement of Its Disc During Prolonged Clenching
Purpose
The effect of the frictional coefficient in the temporomandibular joint on the disc during prolonged clenching was examined.
Materials and Methods
For this purpose, a finite element model of the temporomandibular joint based on magnetic resonance images from a volunteer subject was used. Muscle forces applied for clenching were used as a loading condition for stress analysis during 10 minutes. With respect to the frictional coefficient between articular surfaces, 3 different values ranging from μ = 0.001 to μ = 0.1 were established.
Results
At the onset of clenching, large stresses were found in the central and lateral part of the intermediate zone in the disc, and its stress distribution was not markedly changed during 10 minutes of clenching. In the retrodiscal tissue, stress relaxation occurred during the first 2 minutes of clenching. When the frictional coefficient between articular surfaces increased, the anterior, lateral, and central points in the disc moved further forward. At the end of 10 minutes of clenching, the disc showed a more anterior position as the frictional coefficient increased.
Conclusion
This result indicates that increase of the frictional coefficient between the articular surfaces may be a major cause for the onset of the disc displacement.
⁎Associate Professor, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
†Graduate Student, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
‡Associate Professor, Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands.
§Professor and Chair, Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands.
∥Graduate Student, Department of Systems and Human Science, Osaka University School of Engineering Science, Osaka, Japan.
¶Professor and Division Chair, Division of Mechanical Science, Department of Systems and Human Science, Osaka University School of Engineering Science, Osaka, Japan.
#Professor and Chair, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
Address correspondence and reprint requests to Dr Tanaka: Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
ABSTRACT