The condylar asymmetry-age relationship in determining myogenous or arthrogenous origin of pain in patients with temporomandibular disorders.

The relation of age to asymmetry index of the condyles of the temporomandibular joint differs for groups of patients with a myogenous and arthrogenous origin of pain. It was decided to investigate if this has clinical diagnostic significance. Twenty-eight patients complaining of temporomandibular disorders (TMD) were included in this study. All were dentate with a maximum of five missing teeth including third molars allowed. Condylar asymmetry was measured according to the method of Habets, and this was used to compute the expected patient age for both curves. The patient was assigned to the group with computed age closest to true age. The association between category derived from graphs and that from clinical diagnosis was studied. There was agreement clinically and graphically in 25 of 28 patients. The Kappa statistic to explore the agreement between the two methods gave a value of 0.78, which allows rejection of the hypothesis that agreement was based on chance alone.