Orthognathic surgery-related condylar resorption in patients with skeletal class III malocclusion versus class III malocclusion: a systematic review and meta-analysis.

backgroundOrthodontic-orthognathic treatment is the standard of care for moderate and/or severe skeletal class III (SCIII) malocclusion. Following orthognathic surgery, morphological changes in the temporomandibular joint structures (TMJ) may contribute to condylar resorption (CR).

objectivesThis systematic review aimed to identify the morphological signs of condylar resorption (changes in the condylar head, position, neck, disk, and joint space) following orthognathic surgery in patients with SCIII compared with those with skeletal class II (SCII) malocclusion. Furthermore, surgical techniques were assessed to investigate the extent to which orthognathic surgery may be related to TMJ disorders and potential muscular changes.

methodsA systematic search was conducted using Medline, Pubmed, Scopus, Cochrane Library, Web of Science, and Grey Open literature databases [May 2023; PROSPERO: CRD42021293105)]. Articles that met the eligibility criteria were assessed for quality and the risk of bias using MINORS. A meta-analysis was also conducted.

resultsEleven of the 1014 studies met the eligibility criteria. Of the eligible studies, 10 were considered high-quality. Our results indicated that the incidence of condylar resorption was higher in the SCII group (46.7%) than in the SCIII group (37.2%). The condylar angle was preoperatively higher in the SCII group, and this tendency did not change during the follow-up period. No statistically significant differences in condylar width (95% CI: - 0.62 to 0.43; p = 0.72), height changes (95% CI: - 0.92 to 0.46; p = 0.46), ramus angle (95% CI: - 0.63 to 2.56; p = 0.24) were found between groups. The results suggested that TMJ symptoms were similar between the groups pre- and postoperatively. However, the SCII group showed a higher incidence of anterior disc displacement. Furthermore, postoperative cross-sectional measurements of the lateral pterygoid, medial pterygoid, and masseter muscles were significantly different between the groups.

conclusionCR could be related to specific skeletal pattern, and the extension of surgical movements may be a risk factor. However, the definition of CR remains vague, and no categorization system regarding SCIII patients has been reported to date.