抄録
Recently, so called TMJ dysfunction has been increased, but its mechanism and causes are not clear.
We have made researches about TMJ dysfunction by observation and analysis of chewing movement.
The purpose of this study is to examine the effect of human anterior crossbite on their chewing patterns and know a relation between the anterior crossbite and TMJ dysfunction.
The conclusions are as follows:
1. Anterior crossbite was assorted two types. One was functional anterior crossbite of which chewing pattern showed convergence, the other was just morphological anterior crossbite of which pattern showed no convergence. The convergence was found remarkably on the frontal plane and the horizontal plane, but on the sagittal plane, it was not apparent.
2. The subjects whose chewing pattern showed convergence had symptoms of TMJ dysfunction.
3. The convergence was hardly found on the subjects whose type of occlusion was cuspid protected occlusion, it was suggested that cuspid protected occlusion covered the effect of anterior crossbite, and as a result, TMJ dysfunction was not appeared.
