抄録
Although the movement of the articular disc and condyle of the temporomandibular joint (TMJ) with reciprocal clicking have been investigated from autopsies of specimens using arthrography and cineradiography, no attempts have been made to analyze the clicking from the standpoint of the relationship of the disc position and morphology to condylar movement. This paper reports the disc's positional alternation to the condylar path deflection by using a magnetic resonance imaging system and a six degrees of freedom jaw tracking device equipped with a joint sound recorder for 18 TMJs with reciprocal clicking in 13 subjects. The interincisal distance was measured to recognize the timing of disc reduction and deflection of the condylar path. The results were as follows:
1. Clicking occurred at a low frequency and with a lesser intensity by decreasing the velocity of the open-close jaw movement.
2. It was found that the velocity of the opening click in the late stage was larger (77%) than those in the intermediate (6%) or early stages (17%).
3. The rate of timing coincidence of disc reduction and deflection of the condylar path was as high as 89% for a closing click, and 33% for opening click.
Since accurate analysis of the disc and condylar movement was possible at closing click, it was possible to find the indication or contraindication of treatments using such devices as repositioning appliances.
