Clinical effects on masticatory muscle activity after temporomandibular disorder treatment: A systematic review

OBJECTIVE: To determine whether temporomandibular disorder (TMD) treatments produce changes in masseter and temporalis electromyographic (EMG) activity and to describe the EMG methods used. Methods: Randomized controlled trials assessing EMG before and after TMD treatment, with at least one clinical outcome, were systematically reviewed. Methodological quality and risk of bias were assessed using the PEDro scale and Cochrane RoB-2 tool. METHODS: Randomized controlled trials assessing EMG before and after TMD treatment, with at least one clinical outcome, were systematically reviewed. Methodological quality and risk of bias were assessed using the PEDro scale and Cochrane RoB-2 tool. RESULTS: Of 5,455 records, 10 studies including 350 individuals with TMD were eligible. Interventions included occlusal splints, botulinum toxin, physiotherapy, and complementary therapies. EMG protocols varied markedly, particularly in contraction tasks, recording duration, repetitions, and normalization. Clinical improvements were frequently reported but were not consistently accompanied by changes in EMG activity. Six studies had high risk of bias. CONCLUSIONS: Current evidence does not support consistent effects of TMD treatments on masticatory muscle activity. Methodological limitations and nonstandardized electromyography protocols highlight the need for high-quality research to clarify their neuromuscular effects.