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

NCT07560670 | Completed

• 1 other identifier: IstanbulKentU
• Study Type: observational
• Target: 50
• Locations: 1 country
• Sites: 1

Brief 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

Keywords

Temporomandibular Joint Disorders; Jaw Function; Posture; Bruxism; Muscle Stiffness; MyotonPro; Pain Threshold; Algometry; Perceived Stress; Sleep Quality; Epworth Sleepiness Scale; Jaw Functional Limitation Scale (JFLS-20); PostureScreen Mobile; Young Adults; Comparative Cross-Sectional Study

Outcome Measures

Primary Outcomes (4)

• Jaw Functional Limitation Total Score Assessed Using the 20-Item Jaw Functional Limitation Scale (JFLS-20)

  Jaw functional limitation will be assessed using the 20-Item Jaw Functional Limitation Scale (JFLS-20). The outcome measure will be the total JFLS-20 score, ranging from 0 to 10 (mean global score; 0 = no limitation, 10 = severe limitation). Higher scores indicate greater jaw functional limitation (worse outcome).

  At baseline (study enrollment)

• Pain Intensity and Pain Threshold

  Pain intensity will be assessed using the Visual Analog Scale (VAS), recorded as a score on a 0-10 cm (veya 0-100 mm, hangisini kullanıyorsanız) scale, with higher scores indicating greater pain intensity.Pressure pain threshold will be assessed using a digital algometer and recorded as pressure values (kg/cm², N/cm², ya da kullandığınız birim ne ise onu yazın), with higher values indicating higher pain threshold.

  At baseline

• Postural Alignment Parameters Assessed Using the PostureScreen Mobile® Application

  Postural alignment parameters, including head position, shoulder alignment, spinal posture, and pelvic alignment (uygun olanları siz düzenleyin), will be quantitatively assessed using the PostureScreen Mobile® application.

  At baseline

• Muscle Stiffness (N/m) of the Masseter, Temporalis, and Trapezius Muscles Assessed Using the MyotonPRO Device

  Muscle stiffness will be quantitatively assessed in the masseter, temporalis, and trapezius muscles using the MyotonPRO handheld myotonometer. Stiffness will be recorded in Newtons per meter (N/m) as the primary biomechanical parameter used for evaluation.

  At baseline

Secondary Outcomes (2)

• Sleep Quality

  At baseline

• Perceived Stress

  At baseline

Study Arms (2)

Bruxism

24 patients diagnosed with bruxism will be included.

Other: Bruxism Assessment Form; Other: Clinical Examination; Other: Patient Evaluation Form; Other: Perceived Stress Scale-10; Other: Posture Assessment; Other: Muscle Stiffness Assessment; Other: The Epworth Sleepiness Scale (ESS); Other: Jaw Function Limitation Scale-20 (MFFS-20); Other: Pain threshold assessment

Healthy

24 healthy individuals will be included

Other: Bruxism Assessment Form; Other: Clinical Examination; Other: Patient Evaluation Form; Other: Perceived Stress Scale-10; Other: Posture Assessment; Other: Muscle Stiffness Assessment; Other: The Epworth Sleepiness Scale (ESS); Other: Jaw Function Limitation Scale-20 (MFFS-20); Other: Pain threshold assessment

Interventions

Bruxism Assessment Form OTHER

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.

Also known as: Bruxism Assessment Questionnaire

Bruxism; Healthy

Clinical Examination OTHER

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.

Bruxism; Healthy

Patient Evaluation Form OTHER

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.

Bruxism; Healthy

Perceived Stress Scale-10 OTHER

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.

Also known as: Perceived Stress Scale

Bruxism; Healthy

Posture Assessment OTHER

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.

Also known as: Posture

Bruxism; Healthy

Muscle Stiffness Assessment OTHER

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

Bruxism; Healthy

The Epworth Sleepiness Scale (ESS) OTHER

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).

Also known as: The Epworth Sleepiness Scale

Bruxism; Healthy

Jaw Function Limitation Scale-20 (MFFS-20) OTHER

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.

Bruxism; Healthy

Pain threshold assessment OTHER

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).

Bruxism; Healthy

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

In the literature, a moderate correlation has been found between the jaw functional limitation scale and pain level in temporomandibular joint dysfunction (r=0.3-0.4). Based on the results of the relevant study, G-power analysis was used to calculate the sample size. The expected effect size for our study was considered moderate at 80% power and an alpha value of 0.05 (effect size=0.4), and we planned to include 24 bruxism patients and 24 healthy individuals.

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Istanbul Kent University: lead

Study Sites (1)

Istanbul Kent University

Istanbul, Turkey (Türkiye)

Location

Related Publications (3)

• Izci B, Ardic S, Firat H, Sahin A, Altinors M, Karacan I. Reliability and validity studies of the Turkish version of the Epworth Sleepiness Scale. Sleep Breath. 2008 May;12(2):161-8. doi: 10.1007/s11325-007-0145-7.

  PMID: 17922157 BACKGROUND

• Szucs KA, Brown EVD. Rater reliability and construct validity of a mobile application for posture analysis. J Phys Ther Sci. 2018 Jan;30(1):31-36. doi: 10.1589/jpts.30.31. Epub 2018 Jan 27. PMID: 29410561; PMCID: PMC5788770.

  BACKGROUND

• Xiong X, Xiao CQ, Yang YC, Li YJ, Cheng QY, Wang XY, Liu Y. Temporomandibular disorder patients with excessive daytime sleepiness present greater pain intensity and reduced jaw function. J Oral Rehabil. 2024 Apr;51(4):639-647. doi: 10.1111/joor.13639. Epub 2023 Dec 15.

  PMID: 38100233 BACKGROUND

MeSH Terms

Conditions

Bruxism; Sleep Initiation and Maintenance Disorders; Temporomandibular Joint Disorders

Interventions

Restraint, Physical; Perceived Stress Scale; Posture

Condition Hierarchy (Ancestors)

Tooth Diseases; Stomatognathic Diseases; Habits; Behavior; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Nervous System Diseases; Mental Disorders; Craniomandibular Disorders; Mandibular Diseases; Jaw Diseases; Musculoskeletal Diseases; Joint Diseases; Muscular Diseases

Intervention Hierarchy (Ancestors)

Behavior Control; Therapeutics; Immobilization; Investigative Techniques; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena

Study Officials

• Emine Nur Demircan, Asst. Prof.

  Istanbul Kent University

  PRINCIPAL INVESTIGATOR

• Berfin Erdemli, Res. Asst.

  Istanbul Kent University

  STUDY DIRECTOR

• Melis Usul, Res. Asst.

  Istanbul Kent University

  STUDY DIRECTOR

• Ozge Okcu, Asst. Prof.

  Istanbul Kent University

  STUDY DIRECTOR

• Fatma Yüce, Asst. Prof.

  Istanbul Kent University

  STUDY DIRECTOR

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: September 27, 2025
• First Posted: May 1, 2026
• Study Start: October 15, 2025
• Primary Completion: November 30, 2025
• Study Completion: April 15, 2026
• Last Updated: May 1, 2026

Record last verified: 2026-04

Locations

TU (1)