A gingivectomy is a surgery used to treat periodontal disease for cosmetic and cleansability purposes.
Certain medications can cause gum overgrowth which produces excess gum tissue and nonphysiologic gum contours(i.e. blood pressure medications, antiseizure medications, antirejection medications from transplant patients). Since the gum contours are too large the teeth appear smaller.
In a gingivectomy, the overgrown, diseased , inflammed, soft tissue is surgically removed. This helps to prevent food and bacteria from being trapped and makes it easier to clean the teeth and gums.