Evaluation of the masseter muscle with ultrasonography in patients with temporomandibular joint degenaration

Aim: The purpose of this study is to investigate the masseter muscle thickness and hardness values of patients with TMJ osteoarthritis by ultrasonography. Material and Method: This study included 40 patients who presented to our faculty with complaints of joint pain in whom osteoarthritis was identified in diagnostic CBCT images and 40 healthy individuals. The masseter muscle thicknesses and masseter muscle hardness of the participants were measured by ultrasonography in a resting state and a state of maximum biting. Results: The mean resting masseter muscle thickness values were found as 0.91 cm in the osteoarthritis patients and 1.00 cm in the healthy individuals. The mean maximum biting masseter muscle thickness values were found as 1.28 cm in the osteoarthritis patients and 1.36 cm in the healthy individuals. The mean resting masseter muscle elasticity index ratio were 2.11 in the osteoarthritis patients and 1.49 in the healthy individuals. The mean maximum biting masseter muscle elasticity index ratio were 4.51 in the osteoarthritis patients and 3.16 in the healthy individuals. The masseter muscle thickness values and the masseter muscle elasticity index ratio of the osteoarthritis patients and the healthy individuals were statistically different in both their resting state and their maximum biting state. Conclusion: Ultrasonography is a reliable method of determining masseter muscle thickness. The muscle thicknesses of the osteoarthritis patients were found to be lower than the healthy individuals in this study. It was also determined that patients with TMJ osteoarthritis had an increase in masseter muscle hardness.