Rapid maxillary expansion effects on masticatory muscle activity: A systematic review and meta-analysis

This systematic review aims to assess the impact of rapid maxillary expansion (RME) on masticatory muscle activity through electromyographic analysis. A systematic review was conducted according to the Cochrane Collaboration guide. The PICO strategy was employed to formulate the clinical question. A comprehensive search review was performed up to September 2022 across five databases (PubMed, Web of Science, Scopus, Embase, and Cochrane) and gray literature (Google Scholar). The risk of bias was performed using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS I) tool. Means and standard deviations were extracted to perform the meta-analysis, and overall quality was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. Nine nonrandomized studies with a moderate risk of bias were included in this systematic review. Meta-analysis of electromyographic data during clenching demonstrated an increase in anterior temporal muscle activity after RME (<i>P</i> < 0,05). By contrast, masseter muscle activity at rest decreased after RME. According to the GRADE approach, the overall quality of evidence of the studies ranged between very low and moderate. RME altered masseter and anterior temporal muscle activities. Understanding the impact of RME on masticatory muscle activity is essential in order to optimize treatment outcomes.