Effects of Pterygomaxillary Separation on Skeletal and Dental Changes After Surgically Assisted Rapid Maxillary Expansion: A Single-Center, Double-Blind, Randomized Clinical Trial.

PURPOSE: Surgically assisted rapid maxillary expansion (SARME) is a procedure routinely performed to correct transverse maxillary deformities and can be performed with or without pterygomaxillary disjunction (PD). The aim of the present study was to measure the effect of the amount of expansion and stability of SARME with or without PD. PATIENTS AND METHODS: We designed and implemented a double-blind, randomized clinical trial. The patients were randomly assigned to 2 groups: group 1, SARME without PD; and group 2, SARME with PD. Cone-beam computed tomography scans were performed at 3 points: baseline (T0), after maxillary expansion (T1), and at the end of the retention period (T2). Dental and bone expansion and dental inclination at the maxillary canine and first molar regions were assessed. Two-way repeated measures analysis of variance was used to evaluate the differences between the 2 groups at the 3 evaluation periods (T0, T1, and T2), using a level of significance of P < .05. RESULTS: A total of 24 patients underwent maxillary surgical expansion (group 1, n = 12; and group 2, n = 12). Both techniques promoted a significant transverse dental expansion in the first molar at T2 (with PD, 5.4 mm; vs without PD, 6.4 mm; change, -6.18 mm to 1.48 mm). However, no statistically significant differences were observed between the 2 groups. The tipping molars at T2 remained at a higher level in the SARME, no PD group than in the SARME, PD group (with PD, 2.3 degrees ; vs no PD, 4.6 degrees for 3 teeth; change, -12.72 degrees to 5.57 degrees ; and with PD, 1.6 degrees vs without PD, 3.6 degrees for 14 teeth; change, -9.96 degrees to 9.83 degrees ). CONCLUSIONS: SARME with and without PD is a reliable method for obtaining maxillary expansion, with slight differences in the patterns of skeletal and dental alterations.