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A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible
Published on: January 28, 2020
Evaluation of post-surgical relapse after mandibular setback surgery with minimal orthodontic preparation
Nam-Ki Lee1, Young-Kyun Kim, Pil-Young Yun
1Department of Orthodontics, Seoul National University Bundang Hospital, Sungnam, South Korea.
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 (T0), 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 T1 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°. 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.