自動電子計測装置を用いたヒトの下顎運動の3次元的研究

Abstract

Protrusive and lateral movements of the mandible were measured in three dimensions by means of a newly developed automatic electronic measuring system. Eleven males, average age of 24 years, without any TMJ symptoms were selected as subjects, All measurements were repeated three times under teeth contact and contact free conditions. Digital data of the condylar, molar and incisal paths were computed and statistically compared. The conclusions from the results of this study are;1. Among twenty eight pairs of combinations of condylar, molar and incisal paths analyzed, twenty one of the pairs correlated under p=0.01 level of significance.2. Bennett angle did not correlate to the sagittal lateral condylar path inclination, even at p=0.05 level of significance. Hanau's expression L=H/8+12 is not acceptable for accurately reproduce mandibular movement.3. A correlation coefficient of 0.985 was found between the total sideshift consisting of the lateral component of progressive sideshift, immediate sideshift, and the lateral component of Bennett movement. The lateral shift of Bennett movement and medial shift of the nonworking condyle are the same phenomenon.4. There was correlation between the sagittal protrusive condylar and the sagittal protrusive incisal path inclinations and between the sagittal lateral condylar and the satiggal lateral incisal path inclinations from p=0.05 to p=0.001 level of significance, respectively. The condylar path is one of the determinants of the incisal path. Since the data showed diviation, the condylar path was not the only determinant but other parameter exist.5. The condylar path and molar path showed higher correlation than the condylar path and incisal path. This was due to anatomical positional relationship among the three paths.6. Although Gysi stated that condylar path and incisal path had equal effect upon the molar path, the incisal path according to this study, had greater effect upon the molar path than did the condylar path.