Orthodontic treatment and temporomandibular joint sounds--a longitudinal study.

Temporomandibular joint sounds are often recognized as a clinical sign of temporomandibular disorders. The purpose of this study was to examine changes in the occurrence and resolution of these sounds in patients before and after orthodontic treatment with full fixed appliances. From a pool of 324 patients who came to a university postgraduate orthodontic clinic specifically for treatment of a malocclusion, 160 were examined before and after orthodontic treatment. When joint sounds were either reported or detected clinically, the patients underwent an audiovisual examination to more precisely and objectively record the occurrence and timing of the sound during mandibular opening and closing. No statistically significant difference could be found in the change in occurrence of joint sounds among patients treated with extraction and nonextraction treatment strategies. Overall, fewer patients had joint sounds at the end of the active stage of orthodontic treatment than before treatment. Also, fewer patients demonstrated reciprocal clicking after treatment than before treatment. Therefore it appeared that orthodontic treatment did not pose an increased risk for developing temporomandibular joint sounds irrespective of whether extraction or nonextraction treatment strategies were used. A progression of signs or symptoms to more serious problems was not apparent over the time period studied.