From the Research
The levator labii superioris alaeque nasi (LLSAN) muscle is the primary target for botulinum toxin (Botox) injections when treating a gummy smile, as evidenced by the most recent and highest quality study 1. This muscle elevates the upper lip and exposes excessive gingival tissue when smiling. The LLSAN muscle is responsible for this action, and its injection with botulinum toxin can effectively reduce gum exposure. Typically, 2-4 units of Botox are injected on each side at the point where the muscle originates near the alar base (beside the nose), although the Yonsei point has also been identified as a potential injection site 1. The toxin works by temporarily paralyzing the muscle, preventing it from contracting excessively during smiling, which reduces gum exposure. Results typically appear within 3-7 days and last 3-4 months before retreatment is needed. Sometimes adjacent muscles like the levator labii superioris or zygomaticus minor may also be injected depending on individual anatomy. Patients should avoid rubbing the area for 24 hours post-injection and remain upright for 4 hours to prevent toxin migration. Key considerations for this treatment include:
- The use of botulinum toxin to target the LLSAN muscle
- The potential for adjacent muscles to be injected
- The importance of proper injection technique to avoid complications
- The need for patients to follow post-injection instructions to minimize risks. This treatment is effective because it addresses the underlying muscular cause of excessive gingival display rather than just treating symptoms, as supported by studies 2, 3.