EMG-Based Evaluation of Occlusal Splint and Masseter Botox Effects on Head and Neck Muscles

NCT07082972 | Recruiting Phase 4

• 1 other identifier: 2025/150 Rev-1
• Study Type: interventional
• Target: 56
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized controlled clinical trial aims to evaluate the individual and combined effects of occlusal splint therapy and botulinum toxin type A (BTX-A) injections into the masseter muscle on the activity of head and neck muscles in patients diagnosed with myofascial pain syndrome (MPS). MPS is a common subtype of temporomandibular disorders (TMD), frequently involving the masticatory and cervical muscles. Despite various treatment modalities, there is still no universally accepted protocol. In this study, 56 adult participants of both sexes, without missing teeth and within a normal body mass index (BMI) range, will be randomly assigned to four groups: BTX-A injection only, occlusal splint only, combined BTX-A and splint therapy, and an untreated control group. Surface electromyography (EMG) will be used to assess muscle activity in the masseter, temporalis, sternocleidomastoid, splenius capitis, and trapezius muscles. EMG recordings will be performed at baseline, 4 weeks, and 12 weeks after the intervention. Pain levels and symptom severity will be assessed using the DC/TMD symptom questionnaire and the Visual Analog Scale (VAS). BTX-A injections will be administered by a neurology specialist (20 IU per masseter muscle), and occlusal splints will be custom-fabricated and fitted for each participant. This study seeks to determine the neuromuscular effects of these treatments-both alone and in combination-on masticatory and cervical muscles and to provide insight into the development of more comprehensive and effective treatment strategies for MPS.

Conditions

Myofascial Pain Syndrome (MPS); Masticatory Muscle Pain

Keywords

Myofascial Pain Syndrome (MPS); Botulinum Toxin; Occlusal Splint; Bruxism; Head and neck muscles; Sternocleidomastoid muscle (SCM); Masseter muscle; Splenius capitis muscle; Electromyography

Outcome Measures

Primary Outcomes (1)

• Electromyography results

  Electromyographic (EMG) recordings will be used to assess changes in electrical activity in the masseter, temporalis, sternocleidomastoid (SCM), trapezius, and splenius capitis muscles. These muscles are often overactive in individuals with bruxism, parafunctional habits, and postural issues. Baseline EMG recordings will be taken at week 0, with follow-up measurements at the 1st and 12th weeks to observe short- and mid-term effects. EMG activity in the masseter and temporalis muscles will be evaluated to assess changes following botulinum toxin injections, focusing on potential reductions in muscle hyperactivity. Occlusal splint therapy will be analyzed in terms of its effect on normalizing muscle activity over time. The combined treatment group will be examined for additive or prolonged effects. The control group will serve as a reference to monitor natural variations in EMG activity.

  12 week

Secondary Outcomes (2)

• Diagnostic Criteria for Temporomandibular Disorders - Clinical Examination Form

  12 week

• Evaluation of Pain and Jaw Function as Secondary Outcomes

  12 week

Study Arms (4)

Botulinum toxin injection group

EXPERIMENTAL

Patients will receive a total of 20 units of botulinum toxin injected into the masseter muscle on each side. EMG measurements will be taken before and after treatment to evaluate changes in muscle activity.

Drug: Botulinum toxin injection

Occlusal splint group

EXPERIMENTAL

Patients will use occlusal splints during sleep. EMG recordings will assess the effect of splint therapy on muscle activity.

Device: Occlusal splint

Botulinum toxin + Occlusal splint combined group

EXPERIMENTAL

Patients will receive 20 units of botulinum toxin injections into the masseter muscle on each side and use occlusal splints during sleep. EMG will monitor the combined effect on muscle activity.

Combination Product: Botulinum toxin + Occlusal splint combined

Control group

NO INTERVENTION

Patients will not receive any active treatment. EMG measurements will observe natural changes over time.

Interventions

Botulinum toxin injection DRUG

Patients will receive a total of 20 units of botulinum toxin type A (Botox) injected into each masseter muscle. The injections will be administered at three standardized sites on each side using a fine needle to ensure accurate delivery. Muscle activity will be recorded using electromyography (EMG) before the injection, and follow-up EMG measurements will be taken at one month and four months post-treatment to evaluate changes in muscle activity and treatment efficacy.

Botulinum toxin injection group

Occlusal splint DEVICE

Patients with myofascial pain syndrome will receive custom-made occlusal splints to wear during sleep. These splints help reduce abnormal muscle activity and relieve pain by redistributing bite forces. EMG measurements will be taken before and during treatment to monitor changes in muscle activity.

Occlusal splint group

Botulinum toxin + Occlusal splint combined COMBINATION_PRODUCT

Patients will receive both botulinum toxin injections (20 units per masseter muscle, injected at three standardized points per side) and will use occlusal splints during sleep. EMG measurements will be conducted before treatment, and at follow-up visits to assess the combined effect of pharmacological and mechanical therapy on muscle activity.

Botulinum toxin + Occlusal splint combined group

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Having a diagnosis of myofascial pain syndrome
• No missing teeth
• No history of previous temporomandibular disorder treatment
• Absence of an arthrogenic temporomandibular disorder

You may not qualify if:

• Pregnancy or lactation; osteoporosis and bisphosphonate use
• Previous botulinum toxin injection to the masseter region
• Bleeding disorders or use of anticoagulant medications
• Presence of systemic muscular or neurological diseases (e.g., myasthenia gravis, ALS)
• Active infection, open wound, or dermatological condition in the facial area
• Undergoing other facial aesthetic procedures (e.g., fillers, PRP, etc.) within the last six months
• Individuals with severe psychiatric disorders or those on regular psychiatric medications
• Patients who are unlikely to comply with the study protocol or complete the follow-up period
• Individuals with a body mass index (BMI) outside the normal range, including underweight or overweight participants, will be excluded from the study.

Sponsors & Collaborators

• Istanbul University: lead

Study Sites (1)

Istanbul University

Istanbul, Vezneciler, 34116, Turkey (Türkiye)

RECRUITING

Related Publications (3)

• Choi KH, Kwon OS, Kim L, Lee SM, Jerng UM, Jung J. Electromyographic changes in masseter and sternocleidomastoid muscles can be applied to diagnose of temporomandibular disorders: An observational study. Integr Med Res. 2021 Dec;10(4):100732. doi: 10.1016/j.imr.2021.100732. Epub 2021 May 16.

  PMID: 34141576 BACKGROUND

• Kaya DI, Ataoglu H. Botulinum toxin treatment of temporomandibular joint pain in patients with bruxism: A prospective and randomized clinical study. Niger J Clin Pract. 2021 Mar;24(3):412-417. doi: 10.4103/njcp.njcp_251_20.

  PMID: 33723117 BACKGROUND

• Yurttutan ME, Tutunculer Sancak K, Tuzuner AM. Which Treatment Is Effective for Bruxism: Occlusal Splints or Botulinum Toxin? J Oral Maxillofac Surg. 2019 Dec;77(12):2431-2438. doi: 10.1016/j.joms.2019.06.005. Epub 2019 Jun 19.

  PMID: 31302066 BACKGROUND

MeSH Terms

Conditions

Myofascial Pain Syndromes; Bruxism

Interventions

Botulinum Toxins; Occlusal Splints

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Tooth Diseases; Stomatognathic Diseases; Habits; Behavior

Intervention Hierarchy (Ancestors)

Metalloendopeptidases; Endopeptidases; Peptide Hydrolases; Hydrolases; Enzymes; Enzymes and Coenzymes; Metalloproteases; Bacterial Proteins; Proteins; Amino Acids, Peptides, and Proteins; Bacterial Toxins; Toxins, Biological; Biological Factors; Orthotic Devices; Orthopedic Equipment; Surgical Equipment; Equipment and Supplies

Study Officials

• Olcay Şakar, Phd Prof.

  Istanbul University

  STUDY DIRECTOR

Central Study Contacts

Afra Avar, DDS

CONTACT

+905398757502; afraavar@gmail.com

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Phd DDS

Model Details: Patients with myofascial pain syndrome will be included, and their muscle activity will be measured using electromyography (EMG).

Study Record Dates

• First Submitted: July 17, 2025
• First Posted: July 24, 2025
• Study Start: September 1, 2025
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: July 24, 2025

Record last verified: 2025-07

Locations

TU (1)