歯科用CTを用いた解剖学的下顎頭運動の多点解析

The aim of this study was to develop a method for integrating morphological coordinates obtained with dental computer tomography (CT) and jaw movement coordinates acquired with a mandibular movement measuring device in order to enable multipoint analysis of anatomical condylar movements to be performed. The study subjects were two volunteers. One of the subjects displayed mandibular deviation and had a deformed condyle (on the deviated side), while the other subject exhibited normal occlusion and had healthy condyles. We placed three lead markers in front of each of the subjectsʼ ears and used them to integrate dental CT–derived morphological volume data and jaw movement data, both of which were obtained while the subjects were in the same seated position. Regarding the reproducibility of the reference point data, the positioning and orientation data obtained with the condylar movement measurement system exhibited maximum standard deviation values of 0.162 mm and 0.0₇4°, respectively, while the equivalent data acquired with the CT coordinate system displayed maximum standard deviation values of 0.068 mm and 0.00₇°, respectively. This suggested that reference point errors had little effect on our multipoint analysis of anatomical condylar movement and that the method used to transform the CT coordinates was highly precise. These results indicate that our method for integrating dental CT–derived coordinates with those acquired using a condylar movement measuring device leads to minimal errors in the positional/rotational data for the reference markers and hence, facilitates multipoint analyses of anatomical condylar movement