3D Positional Changes of the TMJ Condyles of Angle Class II Patients After Mandibular Advancement Surgery by Bilateral Sagittal Split Ramus Osteotomy and Osteosynthesis With Bicortical Interfragmentary Screws

To detect postoperative changes in the position of the mandibular condyles and their impact on the signs and symptoms of temporomandibular disorders (TMD) in patients with Angle class II malocclusion after mandibular advancement surgery.

Twenty-three patients were selected for mandibular advancement by bilateral sagittal split ramus osteotomy (BSSO) and osteosynthesis with interfragmentary screws. Computed tomography (CT) scans of the skull and clinical evaluation were performed before surgery (T1), 14 days (T2), and 6 months (T3) after surgery. Temporomandibular joint (TMJ) pain and pathologic sounds were clinically registered, and the mandibular body and condylar positions were determined by 3D cephalometric analysis of the CT scans.

Statistical results showed a mean mandibular advancement of 3.5 mm, which remained stable 6 months after surgery. Surgery resulted in significant changes in the condylar pitch and position on the X -axis ( P =0.002) and Y -axis ( P =0.002). There was a statistically significant probability of TMJ pain at T2 when the condyle was dislocated laterally along the X -axis ( P =0.007), when the condyle roll changed in the medial direction ( P =0.023), and when the condyle pitch decreased ( P =0.012). However, the overall visual analog scale (VAS) score for TMJ pain and pathologic sounds did not exhibit statistically significant changes over time.

Mandibular advancement surgery using BSSO and osteosynthesis with interfragmentary screws showed stable results after 6 months and did not change the overall course of TMJ signs and symptoms, although there were small but statistically significant changes in the condylar position.