This study looked at whether an injection into the jaw joint (temporomandibular joint, or TMJ) can help people who have pain, clicking, and difficulty opening their mouth due to a slipped joint disc. Thirty patients were randomly assigned to receive one of three injections: platelet-rich plasma (PRP, made from the patient's own blood), a steroid medication (dexamethasone) with a local anesthetic, or a saline (salt water) injection as a comparison. Pain, joint clicking, and mouth opening were measured before the injection and one week later. The study found that both PRP and the steroid injection reduced pain and clicking more than saline, and PRP also improved how wide patients could open their mouth.

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.

Inclusion Criteria:

• Inclusion Criteria:
• Skeletally mature patients aged 18 years or older
• Symptomatic TMJ internal derangement in the form of disc displacement with reduction (DDwR), diagnosed using DC/TMD Axis I clinical criteria
• TMJ arthralgia confirmed by pain reproduced on palpation or provoked by jaw movement
• Clicking sound detectable on palpation or auscultation during opening and closing movements
• Elimination or marked reduction of the click on mouth opening from a protruded position

Exclusion Criteria:

• Intra-articular injection within the previous six months
• Systemic inflammatory arthropathy
• Coagulopathy
• Active local infection
• Low platelet count
• Ongoing antiplatelet or anticoagulant therapy
• Pregnancy

"The dataset supporting the conclusions of this article may be requested from the corresponding author"

"Outcome assessor was fully blinded throughout follow-up. Participants in the dexamethasone and saline arms were blinded to allocation; full blinding was not feasible in the PRP arm due to the visible blood-draw and processing procedure