Outcomes of maxillomandibular advancement (MMA) by dentofacial class: A systematic review and meta-analysis

The aim of this paper was to systematically review and compare the Apnoea-Hypopnoea Index (AHI), Lowest O₂ Saturation (LSAT), Oxygen Desaturation Index (ODI), Epworth Sleep Scale (ESS), and Body Mass Index (BMI) between dentofacial (skeletal) classes I, II, and III before and after maxillomandibular advancement (MMA) for Obstructive Sleep Apnoea (OSA). The PubMed, Scopus, and CINAHL databases were searched from inception to 23 November 2022. Two reviewers screened for articles that reported occlusion/malocclusion class type as I, II, or III, and reported preoperative and postoperative AHI, LSAT, ODI, ESS, and/or BMI. Two reviewers independently screened title/abstracts and subsequently, full-text articles that met eligibility criteria. Preoperative ESS and ODI were significantly higher in Class II (13.77, 95% CI, 11.38% to 16.17% and 47.49, 95% CI, 33.04% to 61.95%) than in Class III (12.47, 95% CI, 9.95% to 14.99% and 32.47, 95% CI, -10.37% to 75.30%) (p < 0.0001). Postoperatively, class I showed the greatest percentage reduction of AHI, with a reduction of 89.61% (95% CI, 84.47% to 94.75%) compared with class II and III (p < 0.0001). Additionally, amongst all malocclusion classes and operative status, meta-regression showed positive correlations between ESS and AHI (r = 0.94, p < 0.001) and ESS and ODI (r = 0.90, p < 0.001). Class I subjects with no dentofacial discrepancy had the greatest improvement in AHI compared with Class II and III. Class II subjects may express more severe ODI and ESS preoperatively compared with Class III subjects. Additionally, subjective outcomes (ESS) may be a predictor for objective outcomes (AHI and ODI) for patients undergoing MMA.