Arthrocentesis Versus Botulinum Toxin Injection in Patients With Temporomandibular Joint Disorders: A Randomized Controlled Trial

Temporomandibular joint (TMJ) arthrocentesis will be performed under local anesthesia using a standard two-needle technique. Two needles will be inserted into the superior joint space, and the joint will be irrigated with sterile isotonic solution (e.g., Ringer's lactate or normal saline, approximately 100-300 mL) to lavage inflammatory mediators and break minor intra-articular adhesions. The procedure will be performed as a single session by a trained oral and maxillofacial surgeon. Patients will be advised to follow a soft diet and may receive standard analgesics as needed following the procedure.

Botulinum toxin type A (Botox) will be injected intramuscularly into the masseter and temporalis muscles bilaterally. Injection sites will be determined by palpation of muscle bulk and activity during voluntary contraction (patients will be asked to clench their teeth to identify the muscle borders and the point of maximal bulk/tenderness). The total dose will be 25-50 units per masseter muscle and 10-25 units per temporalis muscle, administered as a single session. The procedure will be performed by a trained physician experienced in botulinum toxin injection technique. Patients will be monitored for the onset of muscle relaxation effects, expected within days to weeks following injection.