Effectiveness of Arthrocentesis and the Occlusal Splint in Treatment of the TMJ

Introduction: Temporomandibular joint disc displacement is a disorder in which the articular disc is anteriorly displaced from its correct position in relation to the mandibular condyle and mandibular fossa. Traditionally, the initial treatment of disc displacements involves several conservative measures, among them, the stabilizing interocclusal splint. However, in cases where there is associated opening limitation, such as intermittent lock and closed-lock, arthrocentesis has been suggested as another initial treatment modality due to its faster effect in preventing disease progression to a more advanced stage, in addition to reducing the chances of pain chronicity and central sensitization. Objectives: The present study aimed to compare and analyze the effectiveness and benefits of performing arthrocentesis as the initial treatment in patients with DDWR with intermittent lock and in patients with DDWoR, compared to the stabilizing interocclusal splint. Additionally, it had as secondary objectives to characterize the sample according to demographic, systemic, local and psychosocial factors in both groups and to correlate the clinical characteristics of the included patients with the imaging findings of the MRI scans. Methods: A randomized, prospective, longitudinal pilot study was performed. The sample was obtained by convenience from a demand through consultations and referral, among patients treated at the Oral and Maxillofacial Surgery Service of HCFMUSP, from June 2021 to July 2023. Patients with diagnoses of: DDWR intermittent lock and DDWoR with opening mouth limitation. Study patients underwent an initial assessment using a clinical questionnaire (DC/TMD) and underwent an initial TMJ MRI. Then, they were randomly divided into two groups according to the treatment to which they would be submitted: stabilizing inter-occlusal splint (group 1) or arthrocentesis (group 2). After treatment was instituted, patients were evaluated at 1, 2, 3 and 6 months regarding clinical parameters of pain, functionality and psychosocial status.

• Occlusal splint (Procedure): a stabilizing maxillary acrylic occlusal splint was made, flat, total and adjusted in central relation (RC).
• Arthrocentesis (Procedure): The patient then underwent arthrocentesis of the temporomandibular joint itself, following the Nitzan technique.

Primary outcomes

• Jaw function available in mouth opening and moviments of jaw [6 months]: millimeter scale

Secondary outcomes

• Pain available through of Visual Analogue Scale [6 months]: the score is determined by measuring the distance (mm) on the 10-cm line between the "no pain" anchor and the patient's mark, providing a range of scores from 0-10. It's been 0 (without pain) and 10 (worst pain)

Sex: All, ages: 18 Years to 60 Years, accepts healthy volunteers

Inclusion Criteria:

* Patients at least 18 years old;
* Diagnosed with disc displacement with reduction with intermittent block or disc displacement without reduction;
* Availability of clinical follow-up for 6 months.

Exclusion Criteria:

* Pregnant patients;
* Patients undergoing conservative or invasive interventions to treat TMD in the last 6 months;
* Inability to use a stabilizing occlusal splint;
* Presence of toothache, neoplasms or medical contraindication for study participation.