Periodontal disease. Illustration of a section through a human tooth with periodontal disease of its surrounding gum and bone. The tooth's white enamel covers the dentine (yellow) and pulp (purple). Yellow deposits of plaque and tartar (calculus) have built up between the tooth and the gum (pink-red). Plaque consists of food remains, mucus and bacteria. Mineral salts from the saliva may then be deposited in the plaque to form tartar. Irritation by the toxins from these deposits have caused inflammation (periodontitis) and destruction of the gums and bone (pale brown). Gum inflammation alone is called gingivitis. If the tartar is not removed, the tooth will become loose and fall out.