A study on the rotational torque movement of mandible in patients with TMJ closed lock

The mandibular rotational angle and distance were measured during various movements of temporomandibular joint (TMJ) closed lock patients (17 women, 23.9 +/- 6.6 years). The measurements were compared with those of the healthy controls (18 women, 24.0 +/- 1.4 years) using the BioPAK system (BioResearch Inc. Milwaukee, USA), which can analyze mandibular rotational torque movements. During maximum mouth opening movement, the parameters of the patient group were significantly larger than those of the control group in horizontal plane (p < 0.05) but vice versa in frontal plane (p < 0.001). During protrusive movement, the parameters of patients were significantly larger than those of control group in frontal and horizontal plane (p < 0.01, p < 0.05). During lateral excursive movement to the affected side of patients, the parameters were significantly larger than those to the unaffected side in frontal plane (p < 0.05).