Relationship between effectiveness of arthrocentesis under sufficient pressure and conditions of the temporomandibular joint

Purpose: The purpose of this study is to investigate the conditions of the temporomandibular joint (TMJ) relative to the effectiveness of arthrocentesis tinder sufficient hydraulic pressure in patients with chronic closed lock. Patients and Methods: We performed arthroscopic examination and athrocentesis as in initial treatment in 65 closed lock cases (65 joints). Changes in maximum mouth opening and joint pain were examined to determine the effectiveness of the treatment. With respect to the conditions of the TMJ before treatment, we examined the range of maximum mouth opening, joint pain at mouth opening degrees of disc deformity and bone change evident with magnetic resonance imaging, and the degrees of synovitis, cartilage changes, and adhesion in the upper joint space evident from arthroscopic findings. These factors were statistically analyzed by using multiple regression analysis. Results: Two months after treatment the maximum mouth opening of the patients increased by, an average of 9.8 mm (range, 0 to 28 mm). Joint pain at opening mouth improved an average of 64-2% (range, 0 to 100%). A significant inverse correlation was found between the extent of improvement in maximum mouth opening after treatment and the initial maximum mouth opening before treatment. There was no significant correlation between improvement of joint pain and conditions of the TMJ. Conclusion: Pathologic conditions of the TMJ did not have an influence on the efficacy of arthrocentesis under sufficient pressure. This result suggests that this procedure has wider application than arthrocentesis under low pressure. (C) 2005 American Association of Oral and Maxillofacial Surgeons.