Long-term TMJ effects of Herbst treatment: a clinical and MRI study.

The long-term effects of the Herbst appliance on the temporomandibular joint were assessed in 20 patients (10 girls and 10 boys) who had completed treatment an average of 4 years previously. The TMJ analysis comprised of: (1) an anamnestic questionnaire (2) a clinical investigation (manual functional analysis) and (3) magnetic resonance imaging of the left and right joints. The results revealed that the incidence of anamnestic and clinical signs and symptoms of temporomandibular disorders was within the range of "normal" reported in the literature. The frequency of disk displacement was not higher than in asymptomatic populations. When summarizing the anamnestic, clinical and magnetic resonance imaging findings five subjects (25%) exhibited moderate to severe signs of temporomandibular disorders ranging from partial to total disk displacement or "deviation in form" of the condyle. Another three subjects (15%) showed mild symptoms of temporomandibular disorders with either small condylar displacement or subclinical soft tissue lesion. In conclusion, it can be said that Herbst treatment does not seem to have an adverse long-term effect on the temporomandibular joint.