Gum disease is a common condition among adults that occurs when bacteria form biofilms or plaques on teeth, and consequently the gums become inflamed. Some severe cases, called periodontitis, call for antibiotics. Many people have had some degree of gum inflammation, or gingivitis, caused by dental plaque. The gums get red and swollen, and they bleed easily. If left unchecked, the condition can progress to periodontitis. The plaque hardens into tartar, and the infection can spread below the gum line and destroy the tissue supporting the teeth.