Effect of a passive jaw motion device on pain and range of motion in TMD patients not responding to flat plane intraoral appliances

This study was designed to compare the effectiveness of a passive jaw motion device, the Therabite, and wooden tongue depressors (WTD), in patients with temporomandibular joint and muscle disorders, who did not improve after manual manipulation of the mandible and flat bite plane therapy. Forty-three patients were enrolled in the study and were classified as joint or muscle groups according to the Research Diagnostic Criteria for TMD. Twenty-four were assigned to the joint group, and 19 patients were assigned to the muscle group. The patients were assigned at random to three treatment subgroups: 1. passive jaw motion device therapy (Therabite); 2. wooden tongue depressors therapy (WTD); and 3. control group. All subjects received flat bite plane appliance therapy throughout the treatment period. Mandibular range of motion was measured for maximum opening (MO), right and left lateral (Rt. Lateral, Lt. Lateral) and protrusive (Pr) movements. Pain level was also assessed at the beginning and at the end of the treatment. The results suggested that a passive jaw motion device is effective in increasing range of motion in both groups of temporomandibular disorder patients, joint (intracapsular) and muscle (extracapsular). It also appears to decrease pain in patients with temporomandibular disorders. Pain was relieved to a greater degree in the muscle group than the joint group.