This clinical trial aims to compare the multidirectional mandibular mobility following the treatment of TMJ disorders with same-protocol intra-articular injections of PRP and HA. It is questioned whether there is direct clinical evidence of the superiority of PRP or HA in the injection treatment of TMJ disorders.

This study was designed as a two-arm equal-allocation clinical trial with a non-concurrent active treatment control. The study group consisted of consecutive patients receiving PRP injections into the TMJ cavities. The control group consisted of the same number of patients who received HA according to the same protocol. Controls were recruited consecutively, men and women separately, to maintain a consistent male-to-female ratio. The main condition for recruitment was the diagnosis of TMJ pain by a specialist in orthodontics or dental prosthetics and, on this basis, a referral for injection treatment. TMJ pain was diagnosed under the ICOP 2020 guidelines. The treatment was performed at the Maxillofacial Surgery Clinic in Kielce, Poland. The study group received PRP from peripheral venous blood of the elbow bend centrifuged at 160 revolutions per minute for 5 minutes with iFuge D06 (Neuation Technologies Pvt. Ltd, Gujarat, India). The control group received 2% hyaluronic acid Synocrom Forte (Croma-Pharma GmbH, Leobendorf, Austria). In both groups, 0.4 mL of the solution was injected per joint.

Inclusion Criteria:

• ICOP 2020 diagnosis of TMJ pain;
• informed consent to participate in the study;
• the possibility of discontinuing the current treatment of the temporomandibular joints;
• generally accepted indications for injection therapy.

Exclusion Criteria:

• active cancer;
• hematopoietic system disease or bleeding diathesis;
• temporomandibular joint prosthesis;
• temporomandibular joint ankylosis;
• skin disease of the preauricular area of the affected side.