This randomized clinical trial will aim to compare the effectiveness of dry needling, lidocaine injection, and mepivacaine injection in the treatment of myofascial pain in the masticatory muscles. A total of 75 participants with bilateral active trigger points in the masseter and/or temporalis muscles will be enrolled and randomly assigned to three intervention groups. Each participant will receive weekly treatments for three weeks. Pain levels, depressive symptoms, and temporomandibular disorder severity will be assessed using the Visual Analog Scale, the Beck Depression Inventory, and the Fonseca Anamnestic Index. Outcome measures will be recorded at baseline and one week after the final treatment session. The primary objective of this study is to determine which intervention provides the greatest improvement in myofascial pain symptoms.

This study will be a randomized, controlled clinical trial designed to compare the effectiveness of dry needling, lidocaine, and mepivacaine injections in the treatment of myofascial pain in the masticatory muscles. Seventy-five participants with bilateral active myofascial trigger points in the masseter and/or temporalis muscles will be recruited. Participants will be randomly assigned to one of three intervention groups: dry needling, lidocaine (20 mg/mL), or mepivacaine (30 mg/mL).

Injections will be administered once a week for three consecutive weeks to both sides of the face. Pain levels will be evaluated using the Visual Analog Scale, depressive symptoms with the Beck Depression Inventory and temporomandibular disorder severity with the Fonseca Anamnestic Index. Measurements will be performed at baseline (prior to first injection) and one week after the third and final injection.

The study will be conducted at Istanbul Medipol University with ethics committee approval. Participants will be informed about the study procedures and informed consent will be obtained from all subjects. The primary objective of the study is to evaluate which intervention provides the most significant reduction in pain and associated symptoms of myofascial pain syndrome. Secondary outcomes will include improvements in depressive symptoms and temporomandibular disorder-related limitations.

Inclusion Criteria:

• Adults aged 18 to 64 years
• Presence of bilateral active myofascial trigger points in both the masseter and temporalis muscles
• Pain provoked by approximately 1 kg of external digital pressure on trigger points
• Willingness to participate and provide informed consent

Exclusion Criteria:

• Previous or ongoing treatment for temporomandibular disorders (e.g., occlusal splints, botulinum toxin injections)
• Presence of systemic neuromuscular disease
• Pregnancy or breastfeeding
• Use of analgesics, muscle relaxants, or antidepressants within the past 2 weeks
• Active infection, tumor, or trauma in the orofacial region