Application of arthrocentesis in temporomandibular joint disorders preferred and suggested therapeutic treatment option in recent years. This study was designed to investigate and compare the effect of intra-articular injection of botulinum toxin-A (Btx-A) on pain and mouth opening after arthrocentesis in nonreduction disc displacement.

This restrospective study was conducted on 30 patients with a visual analogue scale is higher than five and limited mouth opening. Patients were divided into 2 groups as conventional arthrocentesis group (group A) and intra-articular Btx-A injection following arthrocentesis group (group B). Maximum mouth openining and temporomandibular joint pain were measured in preoperative (t0) and at postoperative 1^st-week (t1), 1^st-month (t2) and 6^th-month (t3).

When VAS scores of group A and group B were examined, no statistical difference was observed at t0 and t1 time intervals; an increased in mouth opening values and decreased VAS score values were observed in both groups in the 1^st month (t2) and 6^{th (}t3) months, mostly in group A.

İntra-articular injection of Btx-A following arthrocentesis can induce mouth opening and reduce the pain and dysfunction in patients with anterior disc displacement.