Objective: This study aims to systematically review and meta-analyze the electromyographic activity of masticatory muscles in cleft palate and non-cleft patients, and identify influencing factors.
Design: Systematic Review and Meta-analysis.
Patients and exposures: Patients with cleft lip/ palate.
Comparison: Patients without CL/P.
Main outcome measures: Electrical activity of masseter and temporalis muscles at rest and during peak activation.
Results: After a comprehensive search in MEDLINE, Web of Science, EMBASE, Scopus, and Cochrane's CENTRAL up to December 2022, without language or date restrictions. Eligible trials were selected based on the PECO question and assessed for bias using Cochrane's ROBINS-E tool. Eight clinical trials with 474 participants were included in the review. Then relevant data was extracted from included studies using customized forms. A random-effects meta-analysis was performed to combine the results of the studies, meta-analyses showed that CL/P patients have elevated electrical activity in the masseter (P = .01) and temporalis (P = <.01) muscles at rest compared to non-cleft control patients. During maximum bite force, cleft patients exhibited a statistically significant decrease in electrical activity in both the masseter (P = .03) and temporalis (P = <.01) muscles.
Conclusions: According to our meta-analysis, cleft patients exhibited increased resting muscle activity but decreased activity during maximum bite force, indicating reduced efficiency of masticatory muscles compared to non-cleft patients. These differences can be attributed to anatomical variations, compensatory mechanisms, and previous treatments.
Keywords: cleft lip; cleft palate; electromyography; masticatory muscles; orofacial cleft.