Effect of Occlusal Splint on Head and Neck Muscles in Patients With Bruxism and Myofascial Pain: An Ultrasonographic Study

The study is designed as a prospective observational clinical research. The study group will consist of patients who previously presented with various temporomandibular disorder (TMD) complaints to the "Temporomandibular Disorders Clinic" of the Department of Prosthodontics at the Faculty of Dentistry, Istanbul University. During routine examinations, patients are asked to complete the TMD-DC (Diagnostic Criteria for Temporomandibular Disorders) forms to facilitate accurate diagnosis. Subsequently, patients who are suspected of having TMD of masticatory muscle origin but for whom a definitive diagnosis cannot be established are routinely referred for ultrasonographic (USG) imaging. Patients who meet these criteria will be included in the study.

Participants will be divided into two groups. The first group will comprise patients who have previously undergone USG imaging for routine diagnostic purposes, have been definitively diagnosed with masticatory muscle disorders based on clinical and radiographic examinations, and have initiated occlusal splint therapy as part of routine clinical care. The 12-week treatment protocol of these patients will not be altered in any way. At the final follow-up session at the end of the 12-week treatment period, the TMD-DC form previously completed at baseline will be re-administered, and the two forms will be compared to evaluate changes in patients' symptoms and pain levels. Additionally, a second USG imaging will be performed at this session.

The second group will consist of patients who have undergone USG imaging for routine diagnostic purposes, have been definitively diagnosed with masticatory muscle disorders based on clinical and radiographic findings, but have not yet begun treatment due to waiting their turn in the treatment queue. Patients who start occlusal splint therapy during the study period will be excluded from the control group. This group will serve as the control group of the study. At the end of the 12-week observation period, participants in this group will again complete the TMD-DC form and undergo a second USG imaging. This process will not affect their place in the treatment queue, and treatment will be initiated when their turn arrives.

In the final USG session, the thickness and elasticity of the masseter, temporalis, trapezius, sternocleidomastoid, and splenius capitis muscles will be compared between the two imaging sessions. In this way, the effects of occlusal splints on the morphology and elasticity of the head and neck muscles will be evaluated.