[Echo intensity of the masseter muscle in temporomandibular disorders: a pilot study]

Temporomandibular disorders are common causes of chronic orofacial pain, and their diagnosis is largely based on subjective symptoms, such as pain and its laterality. Ultrasonographic evaluation of the masticatory muscles has traditionally focused on morphological parameters, such as muscle thickness, which provide valuable information; however, these measures alone may not fully reflect the functional and structural condition of muscle tissue. Quantitative assessment of echo intensity may provide an objective and reproducible metric for characterizing structural changes and monitoring clinical status.

The aim of this pilot study was to quantitatively assess masseter muscle echo intensity using ultrasonography in young adults with temporomandibular disorders, with particular emphasis on objective measurability and inter-side differences.

10 young adults (5 patients with temporomandibular disorders and 5 healthy controls) were included in this pilot study. Diagnosis was established according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Bilateral ultrasonographic examination of the masseter muscle was performed, and echo intensity was determined in a standardized manner using ImageJ software.

Total echo intensity was significantly higher in the temporomandibular disorder group compared to the control group (65.64 ± 9.87 vs. 50.39 ± 5.68; p = 0.022). No statistically significant inter-side difference was detected.

Our findings suggest that masseter muscle echo intensity may be sensitive to structural alterations in temporomandibular disorders. The lack of inter-side difference indicates that muscle adaptation may not be limited to the clinically dominant side.

Quantitative ultrasonographic assessment of masseter muscle echo intensity may represent a promising non-invasive method for the objective characterization of temporomandibular disorders. As a quantitative parameter, echo intensity may complement symptom-based diagnostics and provide a tool for monitoring disease progression and treatment response. Orv Hetil. 2026; 167(25): 991-996.