Examination of the disk displacement in the internal derangement of temporomandibular joints using three-dimensional Selspot system

Abstract

Displacement of the articular disk was estimated from the characteristics of the paths of incisal points and kinematic points in both sides of the condyle. The clinical measuring system allowed easy measurement of the three dimensional mandibular movements. The system used two sets of Selspot cameras and light landmark sets, each with three LEDs attached on the upper and lower incisors. The accuracy of the measurement was 0.6mm (0.4 %).
Thirteen subjects with internal derangement of the temporomandibular joint and eleven subjects in normal condition were examined. In the case of anterior disk displacement with reduction, the reduction and redisplacement of the disk were diagnosed by analyzing the paths of kinematic points in the sagittal plane. In the acute cases which were already diagnosed as no-reduction, the progress of disk displacement was estimated quantitavely by comparing the paths of both side kinematic points. The same estimation was achieved by analyzing the path of the incisor in the sagittal and coronal plane.