The purpose of this study was to deepen the knowledge about muscle fatigue of masticatory and facial muscles through analysis of scientific literature. The search strategy was based on the statements of the Cochrane Library. Articles were selected through the PubMed database, using the descriptor “muscle fatigue” in conjunction with the following descriptors: “speech therapy”, “facial muscles”, “jaw muscles”, “mastication”, “chewing” , “lip” and “clenching”. Articles from the last ten years were included, regardless of the language. The texts were analyzed, at first, in its abstract and those that did not fit the study`s objective were excluded. Then, the full texts were analyzed, being considered: aim, study design, control and study groups, criteria and methodological rigor, applied protocols, results and discussion about the presence of fatigue in the targeted muscles. In a last stage, studies that were not in accordance with the purpose of the study, were excluded. Thus, out of 138 articles found, 54 were excluded due to the repetition by crossing key-words and 84 were analyzed. In the abstract analysis, 46 were excluded and 38 were fully analyzed. 24 articles were maintained and 14 were excluded because they do not fit the study`s criteria. Despite there are some studies regarding the analysis of fatigue, their methodology is very varied, making difficult the comparison and detailing. While some studies have found, for example, greater fatigue of the masseter and orbicularis oris muscles, others have not found the same results, which may have influenced the target population for each study.
Muscle Fatigue; Facial Muscles; Masticatory Muscles
