Periodontitis and gingivitis have essential differences. Gingivitis is the early stage of periodontitis. Both gingivitis and periodontitis involve the formation of periodontal pockets, but the pockets in gingivitis are pseudo pockets, caused by inflammation of the gums which leads to the local proliferation or swelling of the gums, enveloping part of the tooth crown. In contrast, the periodontal pockets in periodontitis are true pockets, caused by the resorption of the alveolar bone, a condition that accompanies the loss of alveolar bone. Therefore, the difference between gingivitis and periodontitis lies in whether there is bone loss or not.