Evaluation of post-surgical relapse after mandibular setback surgery with minimal orthodontic preparation

Abstract

Background: The aim of this study was to evaluate of the patterns of post-surgical relapse after mandibular setback surgery with minimal orthodontic preparation (MS-MO). Materials and methods: The subjects consisted of 15 patients with minimal pre-surgical orthodontic preparation (1.37 +/- 1.69 months). Lateral cephalograms were taken in pre-surgical (TO), post-surgical 1 month (T1) and immediately after debonding (T2) stages. To evaluate the surgical changes (T1-T0) and the relapse (T2-T1), the linear and angular measurements were analyzed using paired t-test. Pearson's correlation coefficients of the horizontal and vertical relapses of Pog and Me to other measurements were calculated. Pog or Me in TI were displaced rotationally on Ar-Pog or Ar-Me lines in T2 to evaluate the remaining surgical relapse except the rotational relapse from total relapse. Results: The mandible relapsed anteriorly 3.53 mm (Pog) and 4.00 mm (Me) and superiorly 2.72 mm (Pog) and 2.44 mm (Me). FH to Ar-Pog and FH to Ar-Me decreased by about 2 degrees. Pure surgical relapses at Pog and Me, except rotational relapses, were about 0.5 mm anteriorly and inferiorly 0.8 mm. Conclusion: The vertical relapse might induce mandibular rotation with the horizontal relapse. For an accurate prediction after MS-MO, the rotational relapse might be considered. Crown Copyright (C) 2012 Published by Elsevier Ltd on behalf of European Association for Cranio-Maxillo-Facial Surgery. All rights reserved.