Determining the Relationship Between Posture, Muscle Stiffness, Pain, and Jaw Functionality in Individuals With Bruxism

Bruxism is a repetitive jaw-muscle activity, characterized by teeth clenching or grinding, that may occur during sleep or wakefulness. It is associated with temporomandibular disorders, increased muscle activity, pain, impaired jaw function, and reduced quality of life. Although bruxism has been linked to psychological factors such as stress and sleep disturbances, the relationship between jaw functionality, posture, muscle stiffness, and pain remains unclear. This cross-sectional comparative study will include 48 young adults, consisting of 24 individuals with clinically confirmed bruxism and 24 age-matched healthy controls. Participants will undergo a comprehensive evaluation process. Bruxism will be confirmed by a dental specialist through clinical examination combined with a standardized Bruxism Assessment Questionnaire. Clinical and sociodemographic data will be collected with a patient assessment form. Outcome measures will include: Posture assessment: PostureScreen Mobile® application, using standardized digital imaging. Pain assessment: Pain intensity and thresholds measured with a digital algometer on masseter, temporalis, trapezius muscles, and temporomandibular joint regions. Muscle stiffness: Quantified with the MyotonPro device on jaw and neck muscles. Perceived stress: Evaluated using the Perceived Stress Scale-10. Sleep quality: Assessed with the Epworth Sleepiness Scale. Jaw functionality: Evaluated with the Jaw Functional Limitation Scale-20. Data will be analyzed with SPSS (Version 20.0). Normality will be tested with Shapiro-Wilk. Depending on distribution, parametric or non-parametric tests (Independent Samples t-test, Mann-Whitney U test) will be applied for between-group comparisons. Correlation analyses (Pearson or Spearman) will explore associations among variables. A significance level of p\<0.05 will be adopted. The primary objective is to determine the relationship between jaw functionality, posture, muscle stiffness, and pain in individuals with bruxism. The secondary objective is to examine the impact of perceived stress and sleep quality on these parameters and to compare findings with a healthy control group. This study is expected to fill a gap in the literature by providing evidence on the multifactorial associations between bruxism, postural control, muscle characteristics, and psychosocial factors. Findings may contribute to the development of multidisciplinary preventive and therapeutic strategies in dentistry, physiotherapy, and rehabilitation.