Objectives: The aim of this study was to evaluate of ultrasonographic findings of masseter muscle in females with temporomandibular disorders. Sonographic features were compared in those with myofacial pain disorder (MPD) and temporomandibular click, as well as healthy women.
Methods: Sixty-three females referred to the Prosthetic Department of Dental Faculty of Mashhad University of Medical Sciences (22 with MPD, 21 with click, and 20 control subjects) aged from 20 to 40 years were evaluated. The masseter muscle thickness in each group was measured bilaterally at rest and maximum contraction by a real-time ultrasound imaging technique. The type of the internal pattern of the masseter muscle in sonography was classified to 3 types (I, II, and III) according to the visibility, widths, and echogenicity of internal echogenic bands.
Results: In the right-side masseter, thickness in the control group was greater than that in the MPD group (P = 0.033). There was no significant difference about the thickness of the masseter at rest and at maximum contraction between both sides in control and MPD groups; however, in the click group, the difference was significant. Also, the muscle thickness of either right or left side at rest and at maximum contraction was significant. There was a significant difference between control and MPD groups (P < 0.001) as well as MPD and click groups (P < 0.001) in the type of the internal pattern.
Conclusions: There were obvious ultrasonographic changes of the masseter muscle in females with MPD, which might be related to the muscle inflammation.