Periodontal disease is an infection of the gums, which gradually destroy the bone support of your natural teeth. Dental plaque is the primary cause of gum disease. Bacteria found in plaque produces toxins or poisons that irritate the gums, which may cause them to turn red, swell, and bleed easily. If this irritation is prolonged, the gums separate from the teeth, causing pockets (spaces) to form. As periodontal diseases progress, the supporting gum tissue and bone that holds teeth in place deteriorate. If left untreated, this leads to tooth loss.