Disc displacement within the human temporomandibular joint: a systematic review of a 'noisy annoyance'.

To describe the scientific literature about the diagnosis, prevalence, aetiology, natural course and possible treatment modalities of disc displacements within the temporomandibular (TM) joint. PubMed was searched for specific indexing terms. The search yielded 1211 papers. After screening according to title and abstract, 695 papers were excluded, and after full-text reading, 107 papers remained. Hand-searching of the reference lists resulted in an extra 47 papers. Thirteen studies, published since the literature search was carried out, were also included, resulting in 167 papers for this review. A disc displacement is a highly prevalent derangement within the TM joint, with reported prevalence ranging from 18% to 35% in the general population. A disc displacement with reduction is mostly a stable, pain-free and lifelong condition of the joint. In only a small minority of patients, the disc loses its capacity to reduce on opening. Surprisingly, only in rare cases, the loss of disc reduction is accompanied by signs and symptoms of a closed lock (viz. a painful and limited mouth opening). These signs and symptoms have a tendency to reduce and in many cases to resolve within months. The favourable natural course of disc displacements only warrants active treatment for symptomatic disc displacements without reduction. The primary treatment option is a conservative, non-surgical treatment focusing at speeding up the natural process of alleviation of pain and of improvement in mouth opening. For most patients, a disc displacement is just a pain-free, lifelong lasting, 'noisy annoyance' from their TM joint.