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

Recruiting now · Phase 4

Conditions studied: Myofascial Pain Syndrome (MPS), Masticatory Muscle Pain

In brief

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.

Key facts

Study ID: NCT07082972
Run by: Istanbul University
People needed: 56
Starts: 2025-09-01
Expected to finish: 2026-12-01
Last updated by the study team: 2025-07-24

Who can join

Age: 18 and older, up to 55. Sex: any. Healthy volunteers: not accepted.

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.

Where it is running

Istanbul University — Istanbul, Vezneciler, Turkey (Türkiye) (enrolling)

Full record on ClinicalTrials.gov

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