A gummy smile (excessive gingival / gum display) occurs when a larger than proportionate amount of gum tissue shows above the upper teeth when smiling.

Botox is injected in the area between your upper lip and nose to temporarily freeze the muscles that contract or elevate when you smile which allows you to smile without showing your gums.

There are any number of factors that can cause a gummy smile, including genetics, & overtly powerful lip elevators. Simple muscle relaxing injections can safely & predictably correct a gummy smile