Implications of temporomandibular disorders for facial growth and orthodontic treatment.

The purpose of this article is to review the literature concerning the possible associations between temporomandibular disorders (TMD), orthodontic therapy, mandibular growth, and facial form. Consideration of the association between TMD and orthodontic treatment leads to one conclusion: there is no evidence that orthodontic treatment generally increases or decreases the chances of developing TMD later in life. Still, our understanding of TMD is not final, and the expanding diagnostic knowledge continues to call for new longitudinal studies focusing on the developmental basis of temporomandibular disorders. Little is known about the potential effect of TMD on facial development. However, information relating to the normal development, growth, and adaptation of the temporomandibular joint all tend to emphasize the significant ontogenetic plasticity of the growth-related secondary cartilage associated with the TMJ, within the bounds of normal function and histophysiology. With the exception of such diseases as juvenile rheumatoid arthritis and osteoarthritis, little is known about the influence of TM pathology or myofascial disorders on facial growth. Also, little is known about the possible influence of disc interferences on facial growth. However, the condyle is known to play a prominent role in normal mandibular growth and, consequently, facial development. Thus, categories of TMD that involve dysplasia of the condylar cartilage could be associated with aberrant facial growth and form.