Background and objectives: 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.

Methods: The study enrolled 7 patients with a total of 11 joints, all patients fulfilled stages I or II in 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 four months. Maximum interincisal opening, range of lateral movement and the presence of a click were recorded throughout the follow-up period and an MRI was ordered at the end of the 4 months.

Results: The results pointed out that the decrease in the interincisal opening and side to side movement immediately post-operative was statistically significant, while the difference by the end of the follow-up period was statistically insignificant. Moreover, the joint click disappeared in 91% of the cases by the end of the follow-up period. The MRI showed a marked improvement in disc position postoperatively.

Conclusions: It may be concluded that BTX injection in the LP muscle lead to the disappearance of joint clicking clinically and a significant improvement in disc position as proven by MRI.

Key words: temporormandibular joint; TMJ; click; BTX; BOTOX

Acknowledgements: We would like to express our sincere gratitude to Dr. Amr Maher ‘Professor of General Anesthesia’ for his unconditional support throughout the study and for completing the statistical analysis of this research.