How does botulinum toxin treatment affect the appearance of the upper lip in patients with a gummy smile?

Botulinum toxin treatment for a gummy smile affects the upper lip by inhibiting the contraction of the levator labii superioris alaeque nasi muscle. This results in the lengthening of the upper lip and a reduction in gingival show, enhancing lip fullness and reducing nasolabial folds.

Botulinum toxin treatment targets the levator labii superioris alaeque nasi muscle, which is responsible for the exaggerated retraction of the upper lip that causes a gummy smile. By inhibiting this muscle's contraction, the treatment lengthens the upper lip, reducing the visibility of the gums when smiling. This also contributes to a reduction in deep nasolabial folds and enhances the fullness of the upper lip, improving the overall aesthetic appearance. The effects are typically visible two weeks after treatment and last for about two months, after which muscle function gradually returns.