Does Addition of Medial Pterygoid Muscle Injection Improve the Outcome of Botulinum Toxin Therapy for Masticatory Myofascial Pain Syndrome?

August 16, 2026 updated by: Alshaimaa Ahmed shabaan, Fayoum University

Does Addition of Medial Pterygoid Muscle Injection Improve the Outcome of Botulinum Toxin Therapy for Masticatory Myofascial Pain Syndrome? A Randomized Controlled Clinical Trial

Masticatory myofascial pain syndrome (MMPS) is a common and debilitating orofacial pain condition characterized by localized or referred pain originating from trigger points in the masticatory muscles. The condition significantly impairs quality of life, affecting mastication, speech, and psychosocial well-being. The masseter and temporalis muscles are the most frequently targeted muscles in conventional botulinum toxin type A (BoNT-A) therapy for MMPS; however, the medial pterygoid muscle, a primary jaw-closing muscle, is often overlooked due to its deep anatomical location and the technical challenges associated with its injection.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Current evidence supports the efficacy of BoNT-A in reducing pain and improving mandibular function in patients with localized MMPS. However, the specific contribution of targeted medial pterygoid injection to overall treatment outcomes remains unclear. This study aims to address this gap by evaluating whether the addition of targeted medial pterygoid injection enhances the clinical efficacy of conventional masseter and temporalis BoNT-A therapy.

Study Type

Interventional

Enrollment (Estimated)

111

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Egypt
    • Cairo Governorate
      • Cairo, Cairo Governorate, Egypt, 21523
        • MUST University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of myogenous TMD/myalgia according to DC/TMD.
  • Pain modified by jaw movement, function, or parafunction.
  • Familiar pain reproduced during standardized masseter/temporalis examination.
  • Clinical evidence of medial pterygoid involvement.
  • Medial pterygoid provocation reproduces the patient's familiar pain.
  • Symptoms present for at least 3 months.
  • No major competing odontogenic cause for the patient's pain.

Exclusion Criteria:

  • Predominantly arthrogenous TMD.
  • Trigeminal neuralgia or other neuropathic facial pain.
  • Active systemic inflammatory or infectious disease affecting the masticatory muscles.
  • Significant neuromuscular disease.
  • Pregnancy or breastfeeding.
  • Previous BoNT-A injection into the relevant masticatory muscles during the predefined washout period.
  • Known hypersensitivity to the study medication or formulation components.
  • Local infection at the injection site.
  • Significant bleeding disorder.
  • Clinically significant uncontrolled anticoagulation.
  • Previous major surgery involving the medial pterygoid region that could alter anatomy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Group A
botulinum toxin type A injection into the bilateral masseter and temporalis muscles
Procedure: conventional BoNT-A treatment
botulinum toxin type A injection into the bilateral masseter and temporalis muscles
Experimental: Group B
masseter and temporalis injections , in addition to targeted injection of the clinically involved medial pterygoid muscle
Procedure: conventional treatment plus medial pterygoid injection
masseter and temporalis injections as Group A, in addition to targeted injection of the clinically involved medial pterygoid muscle
Placebo Comparator: Group C
predefined placebo/sham injection protocol
Procedure: Placebo
placebo/sham injection protocol

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
pain intensity
Time Frame: 6 months
a 10-point visual analogue scale (VAS), where 0 revealed no pain and 10 represented the worst imaginable pain
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Fayoum University

Investigators

  • Principal Investigator: Alshaimaa Mohamed, Fayoum University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

August 16, 2026

First Submitted That Met QC Criteria

August 16, 2026

First Posted (Actual)

August 19, 2026

Study Record Updates

Last Update Posted (Actual)

August 19, 2026

Last Update Submitted That Met QC Criteria

August 16, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • MP injection Botox

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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