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NCT Number: NCT07074964

Manual Therapy in Vagus Nerve Neuromodulation for the Treatment of Bruxism

Introduction:

Sleep bruxism is defined as the repetitive activity of the masticatory muscles, characterized by clenching or grinding of the teeth. Studies confirm the association between sleep bruxism and episodes of masticatory muscle activity, with an increase in autonomic sympathetic activity observed during transient periods of sleep. This is associated with nocturnal awakenings, related to increased cardiac, cerebral (cortical arousal), respiratory, and muscular activity.

Objectives: The main objectives are "To study the mean power frequency (MPF) of the masticatory muscles measured by surface electromyography (sEMG) in the general population (with and without bruxism according to ICSD-3 and DC/TMD criteria)"; and "to assess the effectiveness of manual therapy applied to structures adjacent to the vagus nerve based on its impact on orofacial pain and symptomatology in patients with bruxism".

Material and Methods:

A cross-sectional observational study and a randomized controlled experimental study were designed. The first will analyze data collected by sEMG in the masticatory muscles, at rest and during maximum clenching, comparing results between bruxists and non-bruxists. The second will analyze, compared to the control group, data collected on signs (range of motion alteration, presence of sounds), symptomatology (pain, headaches, sensation of blockage, functional limitation) caused by bruxism, sleep quality (Pittsburgh Sleep Quality Index (PSQI)), oral health-related quality of life (OHIP-14), stress and anxiety status (Perceived Stress Scale and GAD-7 (Generalized Anxiety Disorder-7), respectively), and sympathetic-vagal balance (Heart Rate Variability in its frequency and time domains) before and after a manual therapy intervention on structures adjacent to the vagus nerve pathway (head, neck, thorax, diaphragm, abdomen). The collected data will be analyzed using IBM SPSS® version 25.0.0.

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Key information

Conditions

Bruxism, Sleep Bruxism Mental Disorders Nervous System Diseases Parasomnias Sleep Bruxism Sleep Wake Disorders Stomatognathic Diseases Tooth Diseases

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Universitat International de Catalunya (UIC)

Sant Cugat del Vallès, Barcelona, 08195, Spain

Location contact

Maider Sánchez-Padilla, MSc

CONTACT

[email protected]

0034652743302

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Sleep bruxism diagnosed according to the ICSD-III (International Classification of Sleep Disorders, 3rd edition):
  • Regular or frequent tooth grinding sounds occurring during sleep and the presence of one or more of the following clinical signs and symptoms:
  • Abnormal tooth wear consistent with reports of clenching/grinding the teeth during sleep
  • Transient morning pain or fatigue in the jaw muscles; and/or temporal headaches; and/or jaw locking upon awakening, consistent with reports of clenching/grinding the teeth during sleep
  • Sleep bruxism diagnosed according to the RDC/TMD:
  • Interview: During the interview, subjects are asked about the following symptoms: reports of regular or frequent tooth grinding during sleep, muscle fatigue, temporal headache, transient morning muscle pain in the jaw, and jaw locking upon awakening.
  • Physical examination: Presence or signs suggesting abnormal dental wear, such as teeth with flattened cusps and/or loss of contour with dentin exposure.
  • Hypertrophy of the masticatory muscles
  • Dental impressions on the tongue
  • Linea alba on the cheeks along the bite line
  • Damage to dental tissue
  • Excessive dental wear
  • A minimum pain intensity score of 3 on the Visual Analogue Scale at the masseter and temporal algometry points.
  • EMGs with elevated mean power frequency for the masseter and temporalis muscles (to be defined in the first clinical phase-observational study).
  • Age between 18 and 40 years.

Exclusion criteria

  • Having suffered direct trauma, mandibular fractures, or surgeries in the orofacial region.
  • Loss of more than 2 teeth, except for the third molar.
  • Use of muscle relaxant medication or medications that may influence motor behavior.
  • Having received botulinum toxin treatment in the last 6 months.
  • Periodontal disorders or current orthodontic treatment or prosthesis.
  • Partial or total dentures.
  • History of medical disorders (severe psychiatric, physiological, or neurological conditions).

Treatment and study plan

Autonomic nervous system intervention

Other

Manual therapy applied to structures adjacent to the vagus nerve along its pathway. Head: CV4 tecnique and Jugular foramen tecnique; Neck: stretching and mobilization of the superficial and deep layers; Thorax: Longitudinal and transverse translations of the mediastinum; Diaphragm tecniques, Abdomen: Stretching of the gastro-phrenic ligament with lowering of the stomach and general treatment of the small intestine and the mesentery. Stretching, compression and traction movements will be carried out on these structures.

Other names: Intervention

Slight finger pressure

Other

The hands will be placed on areas similar to those in the intervention group, with the fingertips in contact with the skin of the area. A slight finger pressure will be applied, which would not have the same effect as the proposed techniques, since those techniques require a greater intensity of manipulation of the described tissues and structures.

Other names: Control

Primary outcomes

  1. Orofacial Pain

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    Assessment tests for TemporoMandibular Disorder (TMD) and bruxism condition "AXIS- I" is the assessment tool with a "Symptom questionnaire" that ank about pain in 4 questions.

Secondary outcomes

  1. Orofacial Pain (Masseter and Temporalis)

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    Assessment tests for TMD and bruxism condition "AXIS- I" is the assessment tool with a Pressure Pain Threshold of masseter and temporalis muscles with a DC/ TMD EXAMINATION FORM That measures pain intensity by applying one kilogram of pressure to three points on the temporalis, the masseter, and the temporomandibular joint.

  2. Chronic Orofacial Pain

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    Assessment tests for TMD and bruxism condition "AXIS -II" throught the "Graded chronic pain scale version 2.0". It's a self-report questionnaire, typically using a 0-10 numerical rating scale, that evaluates pain intensity and its interference with activities. The GCPS 2.0 classifies patients into different grades of chronic pain from 0 to 4. Higher scores mean a worse outcome.

  3. Range of Motion (subjective)

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    Assessment tests for TemporoMandibular Disorder (TMD) and bruxism condition "AXIS- I" is the assessment tool with a "Symptom questionnaire" that ask about mandibular lock.

  4. Range of Motion (Objective)

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    Assessment tests for TMD and bruxism condition "AXIS- I" is the assessment tool with aa DC/ TMD EXAMINATION FORM that measures mouth opening, protrusion, and lateral movements in millimeters

  5. Jaw Funcionality

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    "AXIS-II" is the assesment tool that include "Jaw Functional Limitation Scale-20 (JFLS-20)". It consists of 20 items that explore the patient's difficulty in performing various activities related to jaw function. Each item is scored from 0 (no limitation) to 10 (severe limitation). A higher score indicates more functional limitation of the jaw.

  6. Oral behavior

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    "AXIS-II" is the assesment tool that include "The Oral Behavior checklist (OBC)"

  7. Functional impact of Headaches in daily life

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    The assessment will be carried out using HIT-6 (Headeach Impact Test-6). It consists of 6 items that assess key areas affected by headaches. The sum of the responses gives a total score between 36 and 78 points. A higher score indicates more impact and disability due to headache.

  8. Sleep Quality

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    Sleep quality is considered one of the most important measures related to bruxism. To assess it, the Pittsburgh Sleep Quality Index (PSQI) questionnaire will be administered. It consists of 19 items answered by the patient and, optionally, 5 additional questions for the bed partner. The 19 items are grouped into 7 components. Each component is scored from 0 (no difficulty) to 3 (severe difficulty). The global score is obtained by summing the 7 components, with a range from 0 to 21 points. A score of 5 or less indicates good sleep quality, while a score above 5 indicates poor sleep quality.

  9. Oral health-related quality of life

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    To assess it, the HIP-14 (Oral Health Impact Profile-14) questionnaire will be administered. It consists of 14 items that explore the frequency of problems related to oral health in daily life. The items are answered on a 5-point Likert scale, ranging from "never" (0 or 1) to "very often" (4 or 5). A higher score indicates worse oral health-related quality of life.

  10. Motor recruitment pattern of the masseter, temporalis, and suprahyoid muscles

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    In resting position and during maximum clenching, as measured by the mean power frequency (MPF) recorded in a surface electromyography.

  11. Stress

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    To assess it, the PSS: Perceived Stress Scale will be administered. It consists of 14 items. It uses a 5-point Likert scale for each item. A higher score indicates more stress.

  12. Anxiety

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    To assess it, the GAD-7 (General Anxiety Disorder-7) will be administered. It consists of 7 items, answered on a 4-point Likert scale. The total score ranges from 0 to 21. A score of 10 or higher is considered the cutoff point for identifying clinically significant anxiety. The higher the score, the greater the anxiety.

  13. Heart Rate Variability (HRV)

    Time frame: From the first assesment (1 week prior to the start of the intervention) to 1 week after the intervention, and data collection on the persistence (1 month, 3 months and 6 months after the end of the intervention). A total of 33 weeks of follow-up.

    Spectral analysis of the time variation between consecutive heartbeats, referred to as the RR interval, which records the activity of the autonomic nervous system. This is collected using the chest strap "Polar H10 Band," which connects to the mobile app "Elite HRV" or "Kubios Software." It collects the frequency measures: LF (low frequency), HF (high frequency), and the ratio between them (LF/HF) as an indicator of sympathetic-vagal balance.

    It collects the time-domain measures: Mean RR interval; SDNN: standard deviation of all RR intervals; pNN50; RMSSD.

Study contacts

Contact information is provided by the study sponsor or research team.

Maider Sánchez-Padilla, MSc

CONTACT

[email protected]

0034 93 589 37 27

Sponsors and collaborators

Lead sponsor

Escoles Universitaries Gimbernat

Other

Collaborators

  • Universitat Internacional de Catalunya

Registry information

Official study title

Efficacy of Manual Therapy in Indirect Non-Invasive Neuromodulation of the Vagus Nerve in the Treatment of Bruxism in Young Adult Population up to 40 Years Old

Acronym: TMBruxism

Important dates

Study start
2025
Primary completion
2027
Study completion
2028
First posted
Jul 20, 2025
Registry last updated
Jul 24, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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