顎関節X線規格写真を用いた顎関節の形態と下顎頭運動経路の分析 : 健常者と顎関節症患者の比較

Abstract

This study reports morphometry of the temporomandibular joint (TMJ) in healthy subjects and comparison of the patients with TMJ dysfunction, which was measured on TMJ radiogram taken by standardized technique. Measurements included length and depth of the mandibular fossa, angle and depth of the articular tubercle, condylar path length and inclination, joint space at the centric occlusion, and distance and angle between the condyle and the tubercle at the maximal opening. A study of the TMJ in healthy subjects showed that there were significant differences between men and women: the women tend to have more gentle articular tubercles and a flatter shape of the TMJ. A study of the TMJ in patients indicates that feminization of the TMJ may be a cause of temporomandibular disorders (TMD) in men. While moving from the centric occlusion to the edge-to-edge occlusion, the mandibular condyle took a significantly steeper course in healthy men than in normal women. The mandibular condyle moved in almost the same manner as healthy subjects in male patients with a closed-locked TMJ, suggesting that most male patients with a closed-locked TMJ can open the mouth. In male patients with a type Ⅲa TMD, the mandibular condyle in the centric occlusion was located more anterior to the mandibular fossa than in healthy subjects; it is suggested that the posterior deviation of the mandibular fossa is not a requirement of the articular disk.