Temporomandibular disorders in the active phase of orthodontic treatment.

Subjective symptoms and clinical signs of temporomandibular disorders (TMD) as well as presence of headache, bruxism and occlusal interferences were examined in 50 patients (mean age 12.9 years) before, during and immediately after orthodontic treatment. The prevalences of signs and symptoms of TMD were high before the treatment in comparison with subjects in an epidemiological study. Except for TMJ sounds, signs and symptoms of TMD as well as presence of headache decreased during the treatment. The major factor for decrease of the dysfunction index during the treatment compared with before the treatment, was tenderness to palpation of the masticatory muscles. Although there was a high prevalence of occlusal interferences during treatment, they seemed to have little importance for development of TMD. One explanation may be that the orthodontically moved teet are sensitive to contact resulting in a decrease of oral parafunctions. Such a decrease was also reported by the patients.