Measuring Study Of Temporomandibular Joint With Three-Dimensional Computed Tomography

Objective: (1). To evaluate veracity and method of measurement of TMJ with 3DCT. (2). To measure three dimensional structure of normal TMJ. It is essential for clinical and laboratory study. (3). To discuss relationships between bone structure change of TMJ and TMD.Material and methods: (1). Bony structures of TMJ were measured on 4 samples of dry skulls. There were two measuring methods which were direct measurement and 3DCT measurement. The comparative analysis of relativity and veracity was carried out. (2). 30 healthy adults were selected. There were 18 men and 12 women, and they were 20 to 50 years old. Both sides of TMJ were scanned with spiral CT, then reconstructed with computed workstation. In ICP, we measured anterior-posterior dimension, left-right dimension and level angles of condyles, anterior-posterior dimension of fossa and posterior pitch of TMJ nub on axial section, we also measured anterior space, upper space and posterior space of TMJ on sagital section. In MOP, the condylar movement (CM) and condylar running angles were measured on sagital section and MIP. The Spee curve was also measured. (3). 30 patients who had been diagnosed clinically as TMD were scanned and measured as the same as normal adults. Every measuring datum was repeated three times, and an average was applied. All data were analyzed.Result: (1). There were no difference between direct measurement and 3DCT measurement on dry skulls TMJs (p>0.05). The two methods were highly correlated. (2). Left and right bony structures of normal condyles and fossae were symmetrical. On sagital section, anterior joint spaces were greater than posterior joint spaces, and the condyles were slightly posterior in the fossae (p<0.01). There were differences between different sections of TMJspaces. The CMs and condylar running angles of normal TMJ were symmetrical too. They were positively correlated with maximum opening distance (MOD). Left and right curvatures of Spec curve were also symmetrical and they were negatively correlated with MOD slightly. (3). Most bony structures of TMD were symmetrical except for level angles of condyles (0.01