Association between malocclusion and temporomandibular disorders in orthodontic patients before treatment.

The association between malocclusion and the prevalence of temporomandibular disorders (TMD) was studied in an orthodontic patient population before orthodontic treatment was started. A total of 305 patients, 232 with general malocclusion and 73 who also had cleft lip or palate, were given a questionnaire about the subjective symptoms of TMD. Clinical examinations for type of malocclusion and TMD signs were also conducted. No significant differences in the prevalence of TMD were observed between the sexes or between the two patient groups. Temporomandibular joint sounds and difficulty of jaw movement were the most common of the TMD signs and symptoms. Open bite, posterior crossbite, and deep bite were the most prevalent types of malocclusion in both groups. Thus, some specific types of malocclusion were significantly associated with the occurrence of TMD.