Influence of Alteration of Tooth Contact on Mandibular Displacement during Lateral Clenching.

To investigate the relationship between occlusal scheme and joint loading, mandibular displacement was measured during lateral clenching under experimentally altered occlusal conditions. Acrylic occlusal devices were fabricated for the lower working-side canine, working-side second molar, and balancingside second molar. With the aid of these devices, various occlusal states were simulated. Eight healthy subjects volunteered for this study and performed clenching tasks. Vertical displacements of the mandible were recorded by linear variable differential transformers, and the results were as follows:1. Clenching efforts in the lateral mandibular position caused elevation of the mandible.2. When a single occlusal device was placed unilaterally, the amount of the upward displacement near the supporting tooth tended to be smallest.3. Insertion of three occlusaldevices (bilateral tooth contacts) reduced the amplitude of mandibular displacement.These results suggested that the nature of reaction forces at the temporomandibular joints caused by the elevation of the mandible would be influenced by the occlusal status.