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

Determining the Relationship Between Posture, Muscle Stiffness, Pain, and Jaw Functionality in Individuals With Bruxism: A Comparative Cross-Sectional Study

Bruxism is a repetitive jaw-muscle activity characterized by teeth clenching and/or grinding, often associated with temporomandibular joint dysfunction, pain, and impaired jaw function. This cross-sectional comparative study aims to investigate the relationship between jaw functionality, posture, muscle stiffness, pain, perceived stress, and sleep quality in young adults with bruxism. A total of 48 participants will be included: 24 individuals with clinically confirmed bruxism and 24 healthy controls.

Clinical and sociodemographic characteristics will be recorded using a Bruxism Assessment Form developed by dentists and physiotherapists. Posture will be assessed with the PostureScreen Mobile® application; pain intensity and thresholds will be measured using a digital algometer; masseter, temporalis, and trapezius muscle stiffness will be evaluated with a MyotonPro device. Perceived stress will be assessed using the Perceived Stress Scale-10, sleep quality with the Epworth Sleepiness Scale, and functional jaw limitation with the Jaw Functional Limitation Scale-20.

Statistical analysis will be performed using SPSS (Version 20.0). Between-group comparisons will be made using t-tests or Mann-Whitney U tests depending on distribution. Correlation analyses (Pearson or Spearman) will be used to evaluate associations among variables.

The primary outcome is to determine the relationship between jaw functionality, posture, muscle stiffness, and pain in individuals with bruxism. Secondary outcomes include the associations of sleep quality and perceived stress with these parameters. This study will provide novel insights into the multidimensional impact of bruxism and may guide future preventive and rehabilitative strategies.

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.

Inclusion Criteria:

• Individuals diagnosed with bruxism following a physical examination and assessment questionnaire administered by a specialist dentist were included in the study.
• Being between the ages of 18 and 30
• Having jaw pain that has persisted for at least 3 months
• Patients who described pain in the face, temporal region, or ear, and who had pain detected in the masticatory muscles upon palpation.
• Volunteering to participate in the study
• Cooperative individuals with whom mutual communication is possible
• Literate

Exclusion Criteria:

• History of surgery or trauma to the maxillofacial region
• Active infection in the maxillofacial region
• Presence of cysts, tumors, or malignant pathologies affecting the TMJ region and muscles
• Presence of systemic rheumatic disease or musculoskeletal diseases affecting the bones
• Presence of any neurological problem that would preclude evaluations
• Diagnosis of any psychiatric disorder
• Receiving physiotherapy or other treatment methods for the TMJ or cervical spinal region within the last 6 months