The goal of this clinical trial is to compare the effectiveness and safety of topical capsaicin cream and topical diclofenac gel in women with chronic temporomandibular joint-related pain. The main questions it aims to answer are:

• Does topical capsaicin reduce pain intensity more effectively than topical diclofenac?
• Do the treatments improve jaw function, pressure pain threshold, and neuropathic pain symptoms?

Researchers will compare topical capsaicin cream with topical diclofenac gel to evaluate differences in pain relief and functional improvement.

Participants will:

• Apply the assigned topical medication four times daily for 7 days
• Attend clinical examinations and pain assessments at baseline, Day 8, and Month 1
• Complete pain-related questionnaires and functional jaw measurements during follow-up visits

This randomized prospective single-blind clinical trial was designed to evaluate the efficacy and safety of topical capsaicin cream compared with topical diclofenac diethylammonium gel in female patients with chronic temporomandibular joint-related pain. Fifty women aged between 18 and 65 years diagnosed with temporomandibular disorders were randomly assigned to either the capsaicin group or the diclofenac group.

Participants in the capsaicin group applied 0.075% topical capsaicin cream, while participants in the diclofenac group applied 1% diclofenac diethylammonium gel. Both medications were applied four times daily over the temporomandibular joint lateral pole region for 7 days. Existing occlusal splint therapy was continued throughout the study period.

Clinical evaluations were performed at baseline, Day 8, and Month 1. Outcome measures included pain intensity assessed with a visual analog scale, multidimensional pain assessment using the McGill Pain Questionnaire, neuropathic pain evaluation using the DN4 questionnaire, pressure pain threshold measurements, maximum mouth opening, lateral mandibular movements, clinician global impression of change, and adverse effects.

The study was approved by the Istanbul University Faculty of Dentistry Clinical Research Ethics Committee and conducted in accordance with the Declaration of Helsinki.

Inclusion Criteria:

• Female participants aged between 18 and 65 years
• Diagnosis of temporomandibular disorder (TMD)-related pain
• Presence of pain for at least 3 months
• Baseline pain intensity sufficient to require treatment
• Willingness to comply with study procedures and follow-up visits
• Signed informed consent form

Exclusion Criteria:

• Pregnancy or breastfeeding
• History of allergy or hypersensitivity to capsaicin or diclofenac
• Presence of systemic inflammatory or neurological disease
• Use of systemic analgesics, corticosteroids, or muscle relaxants during the study period
• Active skin lesions or dermatologic disease in the application area
• Previous temporomandibular joint surgery
• Participation in another clinical trial within the last 30 days
• Inability to comply with study procedures

The decision regarding individual participant data sharing has not yet been finalized.

Participants were blinded to treatment allocation during the study period.