Studies of temporomandibular joint sounds; Part 4. Phase relations of TMJ sounds and jaw movement.

A study was conducted to investigate the timing relationship of temporomandibular joint (TMJ) sounds during mandibular movement, as evaluated by the location of the condyle, in relation to the articular fossa using axiograph recording. TMJ sounds during jaw opening and closing occurred over a wide range: opening sounds were observed within a range of 41-100% of maximum opening, while closing sounds occurred within 1-80% of maximum opening. In calculating the peak frequency of the joint sounds, it was noted that there was no correlation between the timing of the sound and its peak frequency. This study revealed that the acoustic characteristics of TMJ sounds may be unaffected by the location of the condyle.