Posterior disk displacement of the TMJ: MRI evidence in two cases

Posterior disk displacement is a rare temporomandibular joint (TMJ) disorde r. The main clinical sign is sudden molar open-bite (jaw locked in the open position). This may be accompanied by a sensation of intra-articular forei gn body and more rarely joint pain. Joint sounds are unremarkable. Mouth op ening may be slightly impaired. Hypothetically, like anterior disk displace ments, posterior disk displacements can be classified as either reducible o r nonreducible. A definitive diagnosis requires magnetic resonance imaging (MRI). There is no consensus concerning treatment. A conservative course of treatment can be successful in patients with functional impairment and sho uld always be attempted before irreversible, invasive therapy.