Site and severity of facial asymmetry after bimaxillary surgery for class III deformity: a case-control study

Tzu Hsin Wang, Yun Fang Chen, Ying An Chen, Chuan Fong Yao, Tong Xi, Yu Fang Liao*, Yu-Ray Chen

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

Abstract

OBJECTIVES: The study aimed (1) to evaluate the site and severity of facial asymmetry in Class III patients before and after bimaxillary surgery, and (2) to identify the influence of initial severity and positional jaw asymmetry on residual facial asymmetry.

MATERIALS AND METHODS: Preoperative and postoperative cone-beam computed tomography of 65 patients with Class III facial asymmetry who underwent bimaxillary surgery were evaluated. Five midline and 14 paramedian facial soft tissue landmarks were identified to assess facial asymmetry. The outcomes were compared to a control group consisting of 30 age- and gender-matched Class I subjects. The postoperative positional jaw asymmetry (i.e., shift, roll, yaw) of each osteotomy segment (maxilla, mandible, chin, ramus) was also measured.

RESULTS: Before surgery, the asymmetry was more severe at the chin, middle and lower contour. Bimaxillary surgery effectively corrected facial asymmetry, particularly in achieving normalization of chin deviation. However, significant asymmetry persisted postoperatively in the middle and lower contour (p < 0.001 and p < 0.01, respectively), which was affected by the positional ramus asymmetry in the roll and shift.

CONCLUSIONS: Deviation of the chin, middle and lower contour contributed significantly to overall facial asymmetry in Class III asymmetry. Despite normalization of the chin deviation after bimaxillary surgery, asymmetry persisted at the middle and lower contour, primarily as the result of insufficient correction of the positional ramus asymmetry.

CLINICAL RELEVANCE: Understanding the residual asymmetry after bimaxillary surgery is important for minimizing deviation and optimizing the surgical planning for its correction.

Original languageEnglish
Article number334
Pages (from-to)334 - 344
Number of pages11
JournalClinical Oral Investigations
Volume28
Issue number6
DOIs
StatePublished - 23 05 2024

Bibliographical note

© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Keywords

  • CBCT
  • Class III malocclusion
  • Facial asymmetry
  • Orthognathic surgery
  • Outcome
  • Three-dimensional
  • Severity of Illness Index
  • Orthognathic Surgical Procedures/methods
  • Humans
  • Malocclusion, Angle Class III/surgery
  • Male
  • Treatment Outcome
  • Case-Control Studies
  • Cone-Beam Computed Tomography
  • Adolescent
  • Facial Asymmetry/surgery
  • Female
  • Adult
  • Osteotomy, Le Fort
  • Anatomic Landmarks

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