Assessment of association between muscular diagnosis in temporomandibular disorders with mandibular kinematics.

Objective: To study the association between mandibular kinematics and muscular diagnoses in temporomandibular disorders (TMD). Method: Retrospective, descriptive clinical study based on an analysis of 370 clinical records of muscle diagnoses in TMD. Statistical analysis was performed with the SPSS program. Results: Five different muscle diagnoses were considered. Myospasm and centrally mediated myalgia were discarded from the statistical analysis because of their low incidences. The diagnoses included in the analysis were protective co-contraction, myofascial pain, and myalgia. Decreased mandibular kinematics in the frontal and horizontal planes were related to myofascial pain. Mandibular kinematics with deflection in opening values decreased in the frontal plane, but intermediate or increased values in the horizontal plane were related to the protective co-contraction. Muscle pain with normal or increased mandibular kinematics was associated with a diagnosis of myalgia. Conclusion: Values of mandibular kinematics are correlated with the muscular diagnoses in TMD and are useful for diagnosis.