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

Summary

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.

Conditions

• Bruxism
• Posture
• Sleep Quality
• Pain Assessment
• Muscle Stiffness

Interventions

OTHER

Bruxism Assessment Form

To determine the presence of bruxism, the Bruxism Assessment Questionnaire, adapted from internationally accepted scales, will be administered. The questionnaire includes seven questions regarding both sleep and daytime bruxism. The questions were developed based on similar studies. Based on their responses, participants will be classified as having a low, moderate, or high risk of bruxism.

OTHER

Clinical Examination

Participants will undergo a detailed clinical examination by a dentist to diagnose bruxism. The clinical evaluation will be based on the following parameters: a dental examination, a muscle examination, and a jaw joint examination. The dental examination will assess tooth wear, cervical wear, scalloping at the edge of the tongue, the presence of linea alba in the buccal mucosa, and palpation of the masseter, temporalis, and suprahyoid muscles. The jaw joint examination will assess the diagnosis and severity of bruxism by combining mouth opening, clicking or crepitation in the jaw joint, clinical examination findings, and questionnaire scores. Based on the questionnaire and clinical examination results, participants will be divided into three groups: "Probable no bruxism," "Possible bruxism," and "Definite bruxism." A healthy group (n=24) will be formed from the "Probable no bruxism" group, and a patient group (n=24) will be formed from the "Definite bruxism" group.

OTHER

Patient Evaluation Form

The patient evaluation form, developed by the researchers, will be evaluated in detail by the Specialist Dentist after the diagnosis is made. The patient will include the clinical characteristics of the disease, the patient's sociodemographic characteristics, the presence of a chronic or systemic disease, any medications used, the presence of deflection or deviation during mandibular depression, joint noise, the presence of trigger points in the masseter and temporal regions, jaw pain intensity using the Visual Analog Scale (upon waking, during eating, after eating, at bedtime, and temporal headache), and mandibular joint range of motion (painless, maximal, maximal assisted, right lateral and left lateral flexion, and protrusion) using a 10-cm ruler and digital calipers.

OTHER

Perceived Stress Scale-10

The Perceived Stress Scale-10 (PSS-10) questionnaire will be used to assess stress levels. The PSS-10 was developed by Cohen, Kamarck, and Mermelstein (1983). The PSS-10 is a 10-item self-report instrument designed to measure how unpredictable, uncontrollable, and stressful participants perceive their lives to be in the past month. Participants rate each item on a 5-point Likert-type scale ranging from "Never (0)" to "Very often (4)." Total scores range from 0 to 40, with higher scores indicating higher perceived stress levels. Items 6, 7, 9, and 10 are reverse-scored. Its validity and reliability in Turkish were conducted by Eskin et al.

OTHER

Posture Assessment

The PostureScreen Mobile® app will be used to assess posture in a standing position. This app is specifically designed for healthcare professionals who want to objectively assess patients' posture, movement, and body composition. The app calculates a total of thirty-nine variables using images taken from four different angles. It generates an output file containing the calculated values for posture variables and provides visuals showing the positions of the digitized points relative to normal posture. For the posture assessment, participants will be positioned at a designated marked point and asked to stand in a comfortable, neutral posture. Photographs of each participant will be taken from four different angles using the iPad camera. Researchers will take each photo from a distance of 8 feet (approximately 2.4 meters) from the participant. The camera height is not standardized and will be adjusted according to the participant's height.

OTHER

Muscle Stiffness Assessment

Muscle stiffness will be assessed using the Myoton Digital Muscle Palpation Device in the masseter, upper trapezius, and temporalis muscles.

OTHER

The Epworth Sleepiness Scale (ESS)

The Epworth Sleepiness Scale (ESS) was developed by Johns and will be used to assess sleepiness in patients. The ESS is a four-point Likert-type scale. It is scored as 0, 1, 2, or 3, with higher scores indicating increased sleepiness. A score of 0-5 indicates normal daytime sleepiness, 6-10 indicates normal but increased daytime sleepiness, 11-12 indicates increased but moderate daytime sleepiness, 13-15 indicates increased moderate daytime sleepiness, and 16-24 indicates increased severe daytime sleepiness. The ESS is a valid and reliable scale for assessing overall sleepiness levels and can be used in studies on sleep and sleep disorders in Turkey (Cronbach's alpha = 0.86).

OTHER

Jaw Function Limitation Scale-20 (MFFS-20)

The MFFS-20 questionnaire will be used to measure jaw function and limitations during various activities. The scale includes 20 items in the areas of chewing, vertical jaw mobility, and verbal and emotional expression. Items 1-6 address chewing, items 7-10 address vertical jaw mobility, and items 11-20 address verbal and emotional expression of limitations. Patients will be assessed for their limitations on each item using a numerical rating scale of 0 to 10. "0" corresponds to no limitation, and "10" corresponds to severe limitation.

OTHER

Pain threshold assessment

Participants' pain sensitivity to pressure will be assessed using an algometer. A digital algometer (Commender Jtech Medical 801-478 USA) will be used for the assessment. The algometer will measure three times on the body of the masseter muscle, the anterior part of the temporalis muscle, the upper trapezius muscle, and the temporomandibular joint. The algometer will be placed perpendicular to these points, and participants will be asked to report the first time they experience pain. The average of the readings on the display will be read, and the pain threshold will be recorded in pounds (1kg = 2.2 pounds).

Sponsors & Collaborators

• Istanbul Kent University

  lead OTHER

Principal Investigators

• Emine Nur Demircan, Asst. Prof. · Istanbul Kent University

• Berfin Erdemli, Res. Asst. · Istanbul Kent University

• Melis Usul, Res. Asst. · Istanbul Kent University

• Ozge Okcu, Asst. Prof. · Istanbul Kent University

• Fatma Yüce, Asst. Prof. · Istanbul Kent University

Eligibility

Min Age

18 Years

Max Age

30 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-10-15

Primary Completion

2025-11-30

Completion

2026-04-15

Countries

• Turkey (Türkiye)

Study Locations