Botulinum toxin injection for management of temporomandibular joint clicking.

The aim of the present study was to investigate the effect of botulinum toxin type A (BTX-A) injection in the lateral pterygoid (LP) muscle on temporomandibular joint (TMJ) clicking. The study enrolled seven patients with a total of 11 joints; all patients were stage I or II of Wilke's staging for internal derangement. BTX-A was injected in the ipsilateral LP muscle with electromyogram (EMG) guidance and the subjects were assessed for 4 months. Maximum inter-incisal opening, range of lateral movement, and the presence of a click were recorded throughout the follow-up period, and magnetic resonance imaging (MRI) was ordered at the end of the 4 months. The results showed that the decrease in inter-incisal opening and side to side movement immediately postoperative was statistically significant, while the difference by the end of the follow-up period was insignificant. MRI showed a marked improvement in disc position postoperatively. It may be concluded that BTX injection in the LP muscle leads to the disappearance of joint clicking clinically and a significant improvement in disc position as shown on MRI.