Developmental Anomalies of the Temporomandibular Joint.

The processes by which the human face develops in the embryo are exceedingly complex, but they work out perfectly—almost every time. Occasionally, however, the development of structures such as those comprising the temporomandibular articulation is disturbed leading to an anomalous morphology in later life. It is important to note that an anomaly is not necessarily an undesirable condition requiring treatment. It may be benign, with no associated problems, and therefore of no consequence; in fact, it may never be identified. Ross and Johnston have published a review of the developmental processes and etiology of undesirable conditions affecting the temporomandibular joint (TMJ). Craniofacial anomalies may be caused by genetic faults (eg, Treacher Collins syndrome) or caused by a teratogenic agent (eg, thalidomide), but most often it appears the cause is multifactorial (eg, cleft lip and palate). When the entire human genome is available and studied in persons with congenital anomalies, there may well be indicators for, or at least a demonstrable predisposition to, developmental problems. Problems involving the TMJ can be acquired or congenital (developmental). The vast majority seen in a dental office are acquired dysfunctions, traumatic injuries, or pathologic conditions. Developmental anomalies appear to be rare because most of them are asymptomatic and never come to the patient's or dentist's attention. Others are associated with syndromes, and the patients are referred to centers where treatment is provided by multidisciplinary teams of specialists. [ABSTRACT FROM AUTHOR]