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.