The infiltration of Platelet Rich Plasma (PRP) at the end of Temporomandibular Joint (TMJ) arthrocentesis is already an established procedure in the treatment of Temporomandibular Disorders (TMD). Arthrocentesis is a minimally invasive surgical procedure, which aims to eliminate the inflammatory mediators from the inside of the TMJ. PRP is an autologous concentrate of platelets and growth factors, derived from centrifugated blood. Several studies have described the benefits of PRP: it enhances wound healing because of the presence of cytokines and growth factors, and is also stimulates chondrocytes to biosynthesis of collagen. Ropivacaine is a local anesthetic that has been synthesized for use in infiltration anesthesia and to produce both peripheral and central block. Unlike one of its analogues, Bupivacaine, Ropivacaine anesthetize the sensory fibers without affecting the motor ones. The main goal of this investigation is to test the benefits of adding Ropivacaine to the infiltration of PRP in patients submitted to TMJ arthrocentesis.

To investigate the potential reduction of pain in the postoperative week in patients submitted to temporomandibular joint double portal arthrocentesis with lavage and Platelet Rich Plasma (PRP) the authors designed a double-blind randomized clinical trial, comparing a treatment group with additional ropivacaine and a control group without ropivacaine.

Inclusion Criteria:

• Male and female subjects between the ages of 18-99 years;
• For women of reproductive potential: use of highly effective contraception for at least 1 month prior to the first visit and agreement to use such a method during participation in the study;
• In the opinion of the investigator, the subject is capable of understanding and comprehending the study in question;
• The subject signs the written informed consent form and provides the necessary privacy clearance prior to the start of any study procedures;
• Patients with TMD with an indication for TMJ arthrocentesis: clinical and imaging diagnosis of unilateral or bilateral intra-articular disorder;
• Magnetic resonance imaging (MRI) assessing the intra-articular derangement;
• Radiological findings that most components of the joint were salvageable;
• Dimitroulis classification between 2 and 3.

Exclusion Criteria:

• Subject has had other previous minimally invasive or invasive treatment for TMD;
• Subject has any contraindication to the use of ropivacaine according to the Ropivacaine (Fresenius Kabi) bulletin;
• Subject has a history of allergy to any drug in the study;
• Subject taking analgesic medication prior to treatment for other conditions;
• The subject has an inability to interpret pain scales or to read and interpret the study's target questionnaire;
• Women who are pregnant or breastfeeding. For women of reproductive potential, use of highly effective contraception for at least 1 month prior to the first visit is required (Combined oral contraceptive pill, vaginal ring, male and female condom, intrauterine device, diaphragm, injectable hormonal contraceptive) and agreement to use such a method during study participation.
• Subjects under 18 and over 99 years old;
• Subjects diagnosed with the following conditions cannot participate in the study: cardiovascular disorders, peripheral vascular disease, arrhythmias, auriculoventricular conduction disorders, heart failure; hypotension, epileptic patients, patients with liver and kidney disease, patients with porphyria, patients with acidosis.
• Subjects with severe medical problems and mental illness.

Due to data protection policy it is not possible to share this data with other researchers.

The distribution of intervention is performed by attributing a code for each patient. Each code will have been previously distributed randomly between PRP + Ropicavaine and PRP only. The codes are kept closed singularly in an envelope. Before treatment, the nurse will ask the patient to choose an envelope. At this moment, the envelope is placed on a table, and the patient writes his name. Alone, the nurse opens the envelope and sees the code and the indication of PRP or PRP + Ropivacaine. Then, she will prepare, in her room, isolated from the whole team, one 3cc syringe with PRP or PRP + 1cc ropivacaine (7.5mg/ml), depending on the code. Once the code is attributed to the patient, she will deliver a tray with the prepared syringe for treatment. After finishing the arthrocentesis, the doctor injects the chosen treatment. Daily for one week, the patient answers a questionnaire, and at the end of the postoperative week, each patient will be blinded evaluated with a clinical examination.