What is it called when a dentist has to cut open the gums?

Periodontal surgery. An often good wayneo to avoid need for cutting gums to treat gum surgery is with lasers. Find a dentist that does lanap.
Surgery. There are many surgical procedures that require "opening" up the gums: periodontal surgery, apicoectomy, dental implant surgery, removal of impacted teeth, just to name a few; and many dentists who perform these procedures: periodontist, oral surgeon, endodontist, prosthodontist, general dentist. Can you be more specific and tell us why you ask?