Chewing pattern analysis in TMD patients with and without internal derangement: Part I.

In order to investigate the chewing movement of temporomandibular disorders (TMD) patients with and without internal derangement of the temporomandibular joint (TMJ), analysis of the envelope of motion during chewing was performed in 103 TMD patients with unilateral internal derangement (ID group), 94 TMD patients without internal derangement (NID group) and 10 normal subjects (normal group). The analysis of numeric parameters revealed that the ID group demonstrated a significantly restricted range of motion compared to the NID or normal groups, and the NID group demonstrated significant irregularity of chewing compared to the ID or normal groups. The analysis of chewing also demonstrated that the chewing pattern for the ID group demonstrated more frequent deviation of the turning point to the nonchewing side in the frontal plane and a narrow anteroposterior pattern in the sagittal plane compared to the other groups. No characteristic chewing patterns were identified for the NID group.