Relationship between morphologic malocclusion and temporomandibular disorders in orthodontic patients prior to treatment.

The purpose of this study was to investigate the role of malocclusion in temporomandibular disorders (TMD) in an orthodontic patient population prior to treatment. The subjects were 508 Chinese patients (214 males, 294 females), 6 to 56 years of age. The type of malocclusion was diagnosed using dental casts, and TMD signs were recorded by clinical examination. The overall prevalence of TMD signs in the whole group was 26.6%. The frequencies of TMD signs were 44.0% for edge-to-edge bite, 31.2% for posterior crossbite, 27.6% for deep bite, 26.5% for excessive overjet, 26.5% for crowding, 23.7% for anterior crossbite and 23.6% for open bite. Although patients with edge-to-edge bite or posterior crossbite had TMD signs more often than the others in the whole group, the differences did not reach statistical significance. We did not find a significant relationship between morphologic malocclusion and TMD.