A study of condylar movement by bilateral simultaneous videofluorography.

OBJECTIVES

To analyse the condylar movements of patients with temporomandibular disorders and investigate the mutual interaction between both temporomandibular joints (TMJs) by comparing bilateral simultaneous videofluorography with the disk position on MRI.

METHODS

Fifty-two patients who had been diagnosed as having internal derangement in one or both TMJs on the base of the clinical symptoms underwent bilateral simultaneous videofluorography and MRI. The TMJs were classified from the MRI into three categories: superior disk position (SDP), reducing disk displacement (RDD) and nonreducing disk displacement (NDD). Condylar movements of the TMJs were analysed from the videofluorography and correlated with the MR diagnoses.

RESULTS

The range of condylar movement of NDD joints was significantly shorter than that of SDP or RDD joints at maximum mouth opening (P < 0.001), but not at maximum protrusion and lateral protrusion. Based on the sagittal condylar path during maximum mouth opening and closing, three patterns of condylar movement were identified: normal, deflected and short. Sixty-nine per cent of the normal pattern were SDP, 55% of the deflected RDD and 77% of the short NDD. The condylar movement of a NDD or RDD joint could influence the range and pattern of movement of the contralateral joint.

CONCLUSIONS

Analysis of condylar movement was helpful in assessing the state of the disk because they were closely related. The range and pattern of condylar movement of both TMJs were mutually interrelated. Patients with signs and symptoms of internal derangement should have both sides examined for an accurate and complete diagnosis.