Structural study of the temporomandibular joint is a key issue in prosthodontics because the T. M. J. is the most important element of mandibular movement. As three-dimensional investigation is needed in this field, I recently developed a personal computer system that can form three-dimensional images of the T. M. J.. The use of three-dimensional images created by the computer system is effective to research the shape of the T. M. J. and mandibular movements. Using this system, I studied the relationship between mandibular fossa and condyle on mandibular movement.
The results are as follows:
When the condyle movement traces the curve of the frontal wall in the middle of the fossa, the condyle approaches the wall more closely at its inner part than at its outer part.
Three-dimensional images of the T. M. J. can be reconstructed from successive sections of a T. M. J. of a dry skull and by the addition of movement data, mandibular movement can be simulated.