Aim: This study aimed to assess arthrocentesis and a modified anterior repositioning 
splint (ARS) as a therapeutic protocol for management of symptomatic internal TMJ 
derangement, disc displacement without reduction (DDwoR). Subjects and Methods:
Fifteen female patients (30 joints) had TMJ internal derangement (DDwoR) were 
randomly involved in this study. A diagnostic preoperative magnetic resonance 
imaging (MRI) was done for all patients to confirm the diagnosis. A modified ARS was 
constructed for each patient. All patients in this study underwent arthrocentesis and 
wearing a modified ARS. Patients were assessed post-operatively after 1 week, 1 month, 
3 months, and 6 months for pain score by visual analog scale (VAS), maximum mouth 
opening (MMO), and lateral excursions (right and left). Results: Clinical parameters of 
this study showed that pain score means improved from (6.80±1.26) preoperatively to 
(1.53±1.06) at the 6th month postoperatively. Also, improvement in MMO means from 
(26.67±5.47 mm) preoperatively to (43.11±2.08 mm) at the 6th month postoperatively 
was clearly observed. In addition to the obvious improvement in means of the right-side 
lateral excursion as it was (7.00±0.87 mm) preoperatively then became (8.07±0.56 mm) 
at the 6th month postoperatively, also, the left-side lateral excursion means showed the 
same improvement from (6.53±0.90 mm) preoperatively to (8.30±0.56 mm) at the 6th 
month postoperatively. A statistically significant differences between all preoperative 
means and postoperative means in these clinical parameters were clearly observed in 
the study. Conclusion: Arthrocentesis and modified ARS can be considered an efficient 
method for reduction of clinical signs and symptoms of DDwoR of TMJ.