BACKGROUND Temporomandibular disorders are musculoskeletal conditions characterized by facial pain and impaired temporomandibular joint function, limited mouth opening, joint and muscular pain, and noises during mandibular movements are some of the most common symptoms. The most frequent cause of temporomandibular joint dysfunction is internal derangement (ID), which refers to an alteration in the normal pathways of motion of the joint that largely involves the function of the articular disc, therefore, these alterations have been also referred to as disc derangement. Arthrocentesis is a minimally invasive technique, less expensive than surgical treatment. Adhesions are released after arthrocentesis of the upper joint space under sufficient hydraulic pressure. Intra-articular ozone gas injection is used as conservative treatment modalities for ID of the temporomandibular as it possesses anti-inflammatory, analgesic effects, enhancement the host defense mechanism and accelerates the healing process of the damaged cells. OBJECTIVE The aim of this study was to compare the effectiveness of ozonized water against lactated ringer solution in the arthrocentesis of the temporomandibular joint. METHODS Sixty patients were used in this study, suffered from ID of the temporomandibular joint treated by arthrocentesis under hydraulic pressure and were allocated into 2 groups; the study group (A), which included 30 patients, managed by arthrocentesis utilizing ozonized water and the control group (B) with 30 patients also treated by the same procedure using ringer lactate solution. Visual analog scale pain scores, temporomandibular joint sounds, and maximal mouth opening were assessed preoperatively and at different intervals postoperatively. RESULTS The age in this study ranged from 14 to 66 years. The mean age of group A was 29.93 years with an SD of ±11.79. For group B, the mean age was 27.56 years and the SD was ±10.80, the prominent percentage in both groups was < 30 years. Regarding sex, 45 patients were females, whereas the males were 15 with a ratio of 3:1. Group A registered the highest reduction in the visual analog scale at all postoperative intervals. With respect to the mouth opening, there was no significant difference in maximal mouth opening between the 2 groups after 1 week and 12 weeks in comparison with the preoperative measurements. The temporomandibular joint sounds improved in all patients in group A after 12 weeks, whereas in group B the sounds dropped to 33.3%. CONCLUSIONS The data from the present study suggested more favorable treatment outcomes for ozonized water lavage and it is a promising new treatment modality for the relief of symptoms associated with the ID of the temporomandibular joint.