Reliability of mandibular movement assessments depending on TMD.

OBJECTIVE

This study determines the effect of temporomandibular disorders (TMD) on the reliability of mandibular movement assessments.

METHODS

The vertical and horizontal jaw movements, as well as overjet and overbite, were measured twice in 56 consecutively recruited adult subjects with TMD according to the RDC/TMD and 29 controls without TMD diagnosis by experienced dentists utilizing a millimeter ruler. The reliability was determined by intraclass correlation coefficient (ICC).

RESULTS

Neither statistically nor clinically relevant differences in the repeatability between both subgroups could be detected (all p ≥ 0.077). The mouth opening and overjet proved an excellent reliability (ICC 0.85-0.92). Overbite and laterotrusion showed good to excellent reliable results (ICC 0.74-0.82). The second measurement of the vertical jaw movement resulted in systematically higher values (p < 0.003).

DISCUSSION: The assessment of the mandibular movement with a millimeter ruler is a reliable procedure irrespective of TMD. To decrease the variances in the mouth opening measurements, the patient should be asked beforehand to practice this movement.