Evaluation of the Efficacy of Intra-Articular Injection of Platelet-Rich Plasma Versus Dexamethasone With Local Anaesthetic in the Treatment of Internal Derangement of the Temporomandibular Joint: A Randomised Controlled Trial

This was a prospective, parallel-group, three-arm randomised controlled trial conducted at the outpatient clinics of the Maxillofacial and Oral Surgery Division, College of Dentistry, University of Anbar, Ramadi, Iraq. Thirty temporomandibular joints (30 patients) with clinically diagnosed disc displacement with reduction, per DC/TMD Axis I criteria, were randomised 1:1:1 by an independent statistician using a computer-generated sequence, with allocation concealed via sequentially numbered opaque envelopes. The outcome assessor was blinded to treatment allocation throughout follow-up. Patients in the dexamethasone and saline arms were not informed of their specific assignment; full blinding was not feasible for the PRP arm due to the visible blood draw and processing required. All three injections used an identical preauricular approach, injection site, needle gauge, and volume (1 mL) to standardise the procedural experience across groups. Within- and between-group differences were analysed using the Wilcoxon signed-rank test and Kruskal-Wallis test with Dunn post-hoc comparisons. This trial was registered retrospectively after enrolment and follow-up were complete.