Nomenclature and classification of temporomandibular joint disorders.

Currently, there are basically two approaches to classification, one based on structural and one on positional changes occurring within the joint. Despite the increase in knowledge of pathologic changes occurring within the temporomandibular joint (TMJ), the disc still seems to be a central issue in nomenclature and classifications of TMJ disorders. Basic pathologies of the TMJ involve inflammation and degeneration in arthritic disorders (irrespective of the presence or position of the disc) and structural aberrations in growth disorders. Some internal derangements may occur independent of underlying pathology, e.g. because of a traumatic event. In this position paper, a classification of TMJ disorders is proposed based on basic structural changes occurring in the joint.