Assessment of masticatory performance in patients undergoing orthognathic surgery: A systematic review and meta-analysis

BackgroundOne of the main goals of orthognathic surgery is to improve the masticatory performance in patients with maxillofacial deformities. ObjectiveThe aim of this study was to evaluate the literature on assessing masticatory performance before, after orthognathic surgery and normal occlusion. MethodsAn electronic search was performed via Pubmed, Scopus, LILACs and Web of Science without any restrictions until June 2022. The articles assessing masticatory performance using a comminution assay, bite force or occlusal contact area in patients undergoing orthognathic surgery with or without comparing controls were included. The risk of bias of the selected articles was assessed using the appropriate tools according to the study design. ResultsOf the 2507 records identified, 21 studies were included in the qualitative evaluation and 17 studies in the meta-analysis. Nine articles were cohort studies, and the other eight were before-after studies. Moderate to high risks of bias were found among the articles. Comparing the values before and after surgery, the meta-analysis revealed a significant improvement in the bite force and occlusal contact area at 1- and 2-year post-surgery. However, regardless of the assessed parameters, the masticatory performance in patients with normal occlusion was significantly greater than those in patients undergoing orthognathic surgery at all evaluated time points. ConclusionAlthough combined surgical orthodontic treatment can improve impaired masticatory function, assessed by the comminution method, bite force and occlusal contact area, the improvement may not reach that of normal occlusion.