ObjectiveTo identify the available evidence on the ultrasonographic characteristics of masticatory muscles in subjects with myogenous TMD, as well as the potential use of ultrasonography as a diagnostic and treatment assessment outcomes tool.MethodAn electronic search of the PubMed, Web of Science and Scopus databases was performed using the following terms: ‘ultrasonography’, ‘ultrasound’, ‘masseter’, ‘temporal’, ‘masticatory muscles’, ‘temporomandibular disorders’, ‘temporomandibular joint disorders’. Full‐text articles were obtained from the records after applying the inclusion/exclusion criteria.ResultsThirteen articles were included for analysis: one comparative cross‐sectional study, five case–control studies, six clinical trials and one randomised clinical trial. Main ultrasonographic characteristic assessed were local cross‐sectional dimension and intramuscular ultrasonographic appearance. Retrieved studies reported the use ultrasonography for diagnosis or treatment assessment purposes showing heterogeneous results. For diagnosis purposes, the results of local cross‐sectional dimension are not consistent; therefore, its diagnostic value for myogenous TMD diagnosis is weak. However, more homogeneous results were observed for intramuscular ultrasonographic appearance showing a higher prevalence of type‐II pattern in myogenous TMD subjects than non‐TMD subjects. On the other hand, for treatment assessment purposes, muscles were observed thinner after treatment compared to pre‐treatment. Also, results of intramuscular ultrasonographic appearance show disappearance or reduction of anechoic areas, higher prevalence of type‐II pattern and significant distinction of echogenic bands were observed after treating TMD subjects.ConclusionUltrasonography cannot be considered as a diagnostic instrument, but maybe as a complementary tool for treatment assessment of myogenous TMD subjects, even though future research is required to confirm its utility.
