Gingivitis is a condition that is limited to the gum tissues, whereas periodontitis not only affects the gum tissues but also damages the periodontal ligament and alveolar bone. Gingivitis merely involves inflammation of the gum tissues, displaying redness and swelling, as well as changes in the shape, color, and texture of the gums, including bleeding, hypertrophy, and a soft texture. Periodontitis involves not only inflammation of the gums but also leads to attachment loss, formation of periodontal pockets, resorption of the alveolar bone, and loosening or loss of teeth. Gingivitis does not involve bone resorption. In periodontitis, X-rays can show a reduced height of the alveolar ridge, presenting as either horizontal or vertical resorption. For the treatment of gingivitis, supragingival cleaning can completely cure it, allowing gum tissues to return to normal. The treatment of periodontitis, in addition to supragingival cleaning, requires subgingival scaling, root planing, and, when necessary, periodontal surgery to control inflammation, as the resorption of alveolar bone is irreversible.