Gingival fistulas have many etiologies, mainly caused by untreated dental and periodontal infections.
Gradually, apical infection or pulpitis develops, followed by an abscess at the root tip, whose pus can penetrate the bone plate, periosteum and gingiva and drain through a fistula in the gingiva. The fistula can be closed again after the infected material is discharged, and then reopened if a certain amount of pus accumulates, and so on.