Short-term postoperative changes in temporomandibular joints and masticatory muscles of Angle class II patients after mandibular advancement surgery: Clinical findings.

Background and objective: The aim of the study was to detect postoperative changes in the temporomandibular joints (TMJs) and masticatory muscles of Angle class II malocclusion patients who underwent mandibular advancement surgery.

Material and methods: Twenty-three patients were selected for mandibular advancement by bilateral sagittal split ramus osteotomy (BSSO). Cephalograms and clinical evaluation were performed before the surgery as well as fourteen days and six months after surgery. Clinical examination included measurement of overjet, overbite and of the amplitude of mandibular movements, registration of deviation on mouth opening, of TMJ pain and pathological sounds and of tenderness of masticatory muscles on palpation. Mandibular position was determined by cephalometric analysis. Statistical analyses were performed using a mixed-level longitudinal random intercept model with a confidence level of 95% and a P-value of 0.05 to reveal significant differences.

Results: Statistical results showed a mean mandibular advancement of 4 mm (3.1-5.0). Cephalometric measurements, overjet and overbite remained stable six months after surgery. Postoperative amplitude of mandibular movements was limited and did not completely recover 6 months later. Mouth opening was the most affected, showing an average reduction of 7.5 mm six months after surgery. Deviation on mouth opening, pathological TMJ sounds, TMJ pain and masticatory muscle tenderness did not show significant changes.

Conclusions: Moderate mandibular advancement surgery offers stable results, yet the amplitudes of mandibular movements, were significant smaller after surgery and did not completely recovered 6 months following surgery. TMJ and masticatory muscles symptoms did not change after the surgery, suggesting that mandibular advancement surgery does not change the course of TMD.