Bilateral sagittal split surgery is not a predictable treatment for temporomandibular dysfunction in patients with retrognathia.

OBJECTIVE: A prospective study to clarify the impact of forward bilateral sagittal split osteotomy (BSSO) on temporomandibular dysfunction (TMD).

STUDY DESIGN: We examined and interviewed patients with BSSO before and at 1 year after surgery to evaluate the changes in TMD symptoms. A well-known TMD index, which incorporated two complementary subindices-the objective functional Helkimo dysfunction index (Di) and the subjective symptomatic anamnestic index (Ai)-was used. Patients with a forward movement of the mandible and osteosynthesis with titanic miniplates were included.

RESULTS: Forty patients (26 females and 14 males, mean age of study population 36.9 years) retrognathia completed the study. There was no change in TMD symptoms in 24 patients (60%), as measured by the Di, and 26 (65%), as measured by the Ai. Twelve patients improved (30%), according to the Di scores and 10 (25%) according to the Ai scores. Four patients had more TMD symptoms at follow-up (10%), as measured by both Di and Ai.

CONCLUSIONS: Surgery for orthognathia is a predictable treatment for improving aesthetics and occlusion but less predictable for alleviating TMD symptoms in patients with retrognathia. TMD symptoms should therefore be treated independently.