Flap surgery is a type of periodontal surgery used to treat advanced gum disease (periodontitis) that cannot be managed with non-surgical treatments like scaling and root planing. During flap surgery, the gum tissue is carefully lifted or “flapped” back to expose the roots of the teeth and the underlying bone. This allows the dentist to thoroughly clean deep plaque, tartar, and bacteria that have accumulated below the gum line. The procedure may also involve reshaping damaged bone and gum tissue to reduce periodontal pockets, which can trap bacteria and lead to further infection. After cleaning, the gums are repositioned and stitched in place to promote healing.