The mandibular rotational angle and distance were measured during various m
ovements of temporomandibular joint (TMJ) closed lock patients (17 women, 2
3.9 +/- 6.6 years). The measurements were compared with those of the health
y controls (18 women, 24.0 +/- 1.4 years) using the BioPAK system (BioResea
rch Inc. Milwaukee, USA), which can analyze mandibular rotational torque mo
vements. During maximum mouth opening movement, the parameters of the patie
nt group were significantly larger than those of the control group in horiz
ontal plane (p < 0.05) but vice versa in frontal plane (p < 0.001). During
protrusive movement, the parameters of patients were significantly larger t
han 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, t
he parameters were significantly larger than those to the unaffected side i
n frontal plane (p < 0.05).