Ultrasonographic Assessment of Masseter and Anterior Temporal Muscle Thickness and Internal Structure in Young Adult Patients With Bruxism.

Objective: The current study is a comparative cross-sectional analysis study to determine the thickness and internal structure of the masseter muscle (MM) and anterior temporal muscle (ATM) in patients with bruxism by ultrasonography (USG).

Materials and methods: A total of 100 patients (36 males, 64 females), 50 with bruxism and 50 without bruxism, aged 20-30 years were included in the study. All patients were investigated with MM and ATM USG. The thickness of the muscles was measured at rest and during clenching and the internal structure at rest was classified as Type I, II, and III. Differences in the internal structure between bruxism and non-bruxism groups were determined using the Chi-square test (p < 0.05).

Results: The most common internal structure in bruxism was Type 2 in MM (74%) and Type 1 in ATM (46%), whereas in non-bruxism, Type 1 in MM (58%) and Type 1 in ATM (80%) were found most frequently. While there was a statistically significant difference in the internal echogenic pattern in the right MM and ATM in bruxism (p < 0.05), no significant difference was observed on the left side (p > 0.05). Bruxism patients had higher rest and clench thicknesses than non-bruxism patients on both sides in MM and ATM, however, this did not result in a statistically significant difference (p > 0.05).

Conclusions: The results obtained showed that the evaluation of internal structure and thickness differences via USG is crucial in understanding the nature of the bruxism process affecting the masseter and ATM, facilitating its clinical diagnosis and leading to its treatment.