Orthodontic treatment and temporomandibular joint disorders.

The overall objective of this project was to study the relationship between orthodontic treatment and temporomandibular joint (TMJ) disorders. This relationship has been and remains an important and complex issue in orthodontics. The objectives of the study were to determine the incidence of TMJ pain and dysfunction in a group of orthodontic patients who were symptom-free on entering treatment, and to assess and characterize the level of pain and dysfunction in patients with symptoms, and track changes in these parameters during the course of orthodontic treatment. Standardized functional indices and physical measurements were used to describe and assess TMJ pain and dysfunction. The results of this study showed that of 451 patients without symptoms undergoing treatment at our university clinic during the 18-month project, no patient developed signs and symptoms of TMJ disorders during that time. In addition, for the 11 patients who presented with signs and symptoms of TMJ disorders at the time of their entry into the treatment program, no clear or consistent changes in levels of pain and dysfunction occurred longitudinally during the treatment period followed in this study. On the basis of these findings, a relationship between either the onset of TMJ pain and dysfunction and the course of orthodontic treatment or the change in TMJ pain and dysfunction and the course of orthodontic treatment could not be established in this particular patient population.