The relationship between complaints about temporomandibular joint (TMJ) sounds and the prevalence of disc displacements was studied. The rate of incidence of TMJ sounds was 42% in the 50 subjects investigated. In the subjects with TMJ sounds, 19% were diagnosed as having articular disc displacements. In the 58% sound-free subjects, 14% were found to have disc displacements. Therefore, it seems that patients with TMJ sounds do not always have disc displacements, and that a sound-free state does not necessarily indicate a healthy TMJ. Disc displacement was defined on the basis of the following diagnostic criteria:

A study was conducted to investigate the condylar path angle in relation to Angle's classification, amount of overbite and subjective symptoms. The condylar path angle in Angle's Class I group was similar to that in the Class II group. The angle in the Class III group was smaller than in the other two classes. A tendency for the angle to decrease as the amount of overbite became smaller was observed. The angle in the symptom group was slightly smaller than in the no-symptom group.