CLASSIFICATION AND PREVALENCE OF TEMPOROMANDIBULAR-JOINT DISK DISPLACEMENT IN PATIENTS AND SYMPTOM-FREE VOLUNTEERS

The purposes of this study were to develop a classification system for disk displacement in the temporomandibular joint (TMJ) and to study t he prevalence of the various types of TMJ disk displacement in patient s and symptom-free volunteers. The study was based on bilateral MRIs o f 243 patients and 57 symptom-free volunteers. Eight different types o f disk displacements were identified in addition to the superior disk position and a tenth indeterminate category. Superior disk position wa s observed bilaterally in 18% of the patients and bilaterally in 70% o f the symptom-free volunteers.