A study of occlusal relationships and the incidence of myofacial pain.

A survey of 123 subjects (dental students) was performed to evaluate quantitative data that may be of value in the incidence and treatment of myofacial pain. Social statistics, subjective and objective symptoms, and the influence of occlusal interferences on these symptoms were quantitated and recorded. The data indicated that, 123 subjects, 26% had maximum intercuspation of the teeth at terminal hinge closure, 42% had maximum intercuspation of the teeth with the condyles located symmetrically anterior to terminal hinge, and 32.5% had maximum intercuspation of the teeth with assymmetric variations of the condyles anterior to terminal hinge. Averages were obtained for the maximum intercuspal open, the condylar inclination, and the distance anterior from the terminal hinge of both condyles in symmetrical and asymmetrical variations. The location of the transverse (terminal hinge) axis from the external auditory meatus was measured on the ala-tragus line. These latter averages indicate that a significant occlusal discrepancy can result from prevailing techniques of locating an arbitrary hinge axis 10 to 13 mm anterior from the external auditory meatus. The results showed that most subjects demonstrated, both subjectively and clinically, symptoms of neuromuscular dysfunction without occlusal interferences. Therefore, it may be concluded that treatment modalities considered within the first 6 weeks should be conservative and reversible to eliminate or decrease myofascial trigger zones and their areas of referred pain. Alteration of the existing occlusion and maxillomandibular relations may be adjusted with caution, if necessary.