Differences of condylar changes after orthognathic surgery among Class II and Class III patients

Li-Fang Hsu; Yi-Jen Liu; Sang-Heng Kok; Yi-Jane Chen; Yunn-Jy Chen; Mu-Hsiung Chen; Chung-Chen Jane Yao

doi:10.1016/j.jfma.2021.01.018

Differences of condylar changes after orthognathic surgery among Class II and Class III patients

J Formos Med Assoc. 2022 Jan;121(1 Pt 1):98-107. doi: 10.1016/j.jfma.2021.01.018. Epub 2021 Feb 12.

Authors

Li-Fang Hsu¹, Yi-Jen Liu², Sang-Heng Kok³, Yi-Jane Chen⁴, Yunn-Jy Chen⁵, Mu-Hsiung Chen⁶, Chung-Chen Jane Yao⁷

Affiliations

¹ Graduate Institute of Clinical Dentistry, School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Dentistry, National Taiwan University Hospital, Hsin-Chu Branch, Hsin-Chu, Taiwan.
² Graduate Institute of Clinical Dentistry, School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan; Division of Orthodontics and Dentofacial Orthopedics, Dental Department, National Taiwan University Hospital, Taipei, Taiwan.
³ Division of Oral Maxillofacial Surgery, Dental Department, National Taiwan University Hospital, Taipei, Taiwan.
⁴ Division of Orthodontics and Dentofacial Orthopedics, Dental Department, National Taiwan University Hospital, Taipei, Taiwan.
⁵ Division of Prosthodontics, Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan.
⁶ Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan.
⁷ Graduate Institute of Clinical Dentistry, School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan; Division of Orthodontics and Dentofacial Orthopedics, Dental Department, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: janeyao@ntu.edu.tw.

PMID: 33583702
DOI: 10.1016/j.jfma.2021.01.018

Abstract

Background/purpose: The nature of susceptibility to condylar resorption after orthognathic surgery can be different between skeletal Class II and Class III populations, which was addressed by few in the past. The aim of the present study was to use cone-beam computed tomographic (CBCT) images to investigate the displacement and morphological changes of temporomandibular joints (TMJs) in patients received orthodontic treatment combined with orthognathic surgery.

Methods: Both Class III (n = 34) and Class II (n = 17) patients were compared through overall and regional superimpositions of the initial and posttreatment CBCTs. Two-sample t-test was used to identify significance between group differences. Pearson's correlation coefficient was used to address changes of TMJ and the amount of setback or advancement.

Results: The axial ramal angle increased significantly in Class III group and decreased in Class II groups after orthognathic surgery (p < FDR_p). For condylar dimensions, significant widths and lengths reductions were noted only in Class II group. However, no significant difference was found after comparing subgroup differences according to one-jaw and two-jaw options, nor any significant correlation found between the condylar changes and the amount of surgical movements.

Conclusion: The nature of condylar susceptibility could result more from different skeletal patterns than the amount of surgical movements. However, the direction of mandibular surgery may contribute to different changes of condylar angle in axial section.

Keywords: Cone-beam computed tomography; Orthognathic surgery; Temporomandibular joints; Three-dimensional analysis.

MeSH terms

Humans
Orthognathic Surgery*