Efficacy of PRP Injections in Reducing Pain for Myogenous TMD Patients

Platelet-Rich Plasma (PRP) Injections as Treatment for Myogenous Temporomandibular Disorders: A Randomized Clinical Trial

This study aims to evaluate whether intramuscular injections of platelet-rich plasma (PRP) are more effective than isotonic saline in reducing pain and improving jaw function in individuals diagnosed with myogenous temporomandibular disorders (TMD). Myogenous TMD is a common source of orofacial muscle pain and functional limitation, and although conservative treatments help many patients, a significant proportion continue to experience persistent symptoms that affect daily life and quality of function.

PRP is an autologous, minimally invasive biologic concentrate enriched with platelets and bioactive molecules that may promote tissue repair and modulate inflammation, making it a promising option for managing muscle-related pain conditions. However, evidence from well-controlled randomized clinical trials in myogenous TMD remains limited.

In this double-blind, randomized controlled clinical trial, participants will receive two intramuscular injections-either PRP or saline-administered one month apart. Follow-up assessments will occur at 1, 3, and 6 months using standardized and validated measures of pain intensity, pain sensitivity, mandibular function, and psychosocial factors.

The results of this study may help determine the clinical value of PRP for myogenous TMD and contribute to future standardization of regenerative treatment protocols in orofacial pain management.

Study Overview

• Status: Not yet recruiting
• Conditions: Myofacial Pain; Myogenic Temporomandibular Joint Disorders; Masseter Muscle
• Intervention / Treatment: Procedure: Platelet rich plasma (PRP); Drug: Saline (0.9% NaCl)

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nikolaos Christidis Professor, PhD; Phone Number: +4685288124; Email: nikolaos.christidis@ki.se

Study Locations

• Sweden
  • Stockholm County
    • Huddinge, Stockholm County, Sweden, 17177
      • Karolinska Institutet - Department of Dental Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• for the experimental part of the project are: women 20 to 50 years with a confirmed diagnosis of myogenous TMD according to the DC/TMD (21). Participants must have pain in the masticatory muscles. Pain duration must be at least 3 months. Participants must report current pain at the day of inclusion with a minimum score of 4 on the numeric rating scale (NRS 0 to 10).

Exclusion Criteria:

• active infection or inflammation at the injection site, systemic infection, platelet or coagulation disorders, severe anemia, autoimmune or inflammatory rheumatic disease, chronic liver disease, uncontrolled diabetes, or active malignancy. Pregnancy or breastfeeding will also be exclusion criteria. Patients using anticoagulant or antiplatelet medication that cannot be temporarily discontinued, or receiving chronic corticosteroid or immunosuppressive therapy, will be excluded. Additional exclusion criteria include predominantly arthralgia temporomandibular disorders, previous temporomandibular joint surgery, or a history of significant trauma to the face, head, or neck, including orthognathic surgery. Patients will also be excluded if they present widespread pain conditions such as fibromyalgia, neuromuscular disorders such as craniomandibular dystonia or myasthenia gravis, diagnosed or severe psychiatric disease such as schizophrenia or bipolar disorder, neuropathic pain, or pain of dental origin. Patients unable to provide informed consent or complete study questionnaires will be excluded.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PRP Injection; PRP Injection (Experimental) Arm Description: Participants in this arm will receive intramuscular injections of platelet-rich plasma (PRP) into the masseter muscles. PRP is prepared using a standardized two-step centrifugation protocol to obtain the platelet-rich fraction. Each session includes injections at three marked points per masseter muscle, with 0.3 mL injected per point (total 1.8 mL per session). A second PRP injection will be administered at the 1-month follow-up visit. All procedures are performed under double-blind conditions.	Procedure: Platelet rich plasma (PRP); PRP Injection (Experimental) Participants in this arm will receive intramuscular injections of platelet-rich plasma (PRP) into the masseter muscles. PRP is prepared using a standardized two-step centrifugation protocol to obtain the platelet-rich fraction. Each session includes injections at three marked points per masseter muscle, with 0.3 mL injected per point (total 1.8 mL per session). A second PRP injection will be administered at the 1-month follow-up visit. All procedures are performed under double-blind conditions.
Placebo Comparator: Saline Injection; Saline Injection (Placebo Comparator) Arm Description: Participants in this arm will receive intramuscular injections of isotonic 0.9% saline into the masseter muscles. The injection technique, number of points (three per masseter), volume per point (0.3 mL), and needle type are identical to the PRP arm to maintain procedural consistency. A second saline injection will be administered at the 1-month follow-up visit. All proc	Drug: Saline (0.9% NaCl); Participants in this arm will receive intramuscular injections of isotonic 0.9% saline into the masseter muscles. The injection technique, number of points (three per masseter), volume per point (0.3 mL), and needle type are identical to the PRP arm to maintain procedural consistency. A second saline injection will be administered at the 1-month follow-up visit. All proce

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Pain Intensity (CPI 0-100)	Change in self-reported pain intensity , measured using a 0-100 Characteristic Pain Intensity (CPI). The assessment will be perform at baseline and at each follow-up.	Baseline, 1 month, 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Maximum Mouth Opening (MMO)	Change in maximum unassisted mouth opening in millimeters, measured using a standardized ruler. Higher values indicate improved mandibular mobility	Baseline, 1 month, 3 months

Collaborators and Investigators

• Sponsor: Karolinska Institutet

Study record dates

Study Major Dates

• Study Start (Estimated): June 4, 2026
• Primary Completion (Estimated): August 30, 2026
• Study Completion (Estimated): December 20, 2026

Study Registration Dates

• First Submitted: May 19, 2026
• First Submitted That Met QC Criteria: May 19, 2026
• First Posted (Actual): May 26, 2026

Study Record Updates

• Last Update Posted (Actual): May 26, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Orofacial Pain; Pain Modulation; Myofascial Pain; Platelet-Rich Plasma; Intramuscular Injection; Regenerative Therapy; Masseter Muscle; Temporomandibuar disorders; Myogenous TMD; PRP Injection
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Facial Pain; Inorganic Chemicals; Chlorine Compounds; Sodium Compounds; Chlorides; Hydrochloric Acid; Sodium Chloride
• Other Study ID Numbers: 2026-01518-01; Karolinska Institutet (Other Identifier: Karolinska Institutet)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No