Two most common oral diseases around the globe are dental caries (disease resulting in tooth decay and eventual loss) and periodontal disease associated with tooth loosening. Dental caries are linked to high–sugar diets as well as poor dental hygiene, resulting in tooth pulp infection. Other factors such as poverty and decreased saliva flow affect the frequency of this disease. The use of fluoride has proved effective against cavities through a variety of different mediums, including its addition to centralized water supplies where possible, as well as salt, toothpaste, milk and fluoride capsules, and rinse. Nationalized oral health programs demonstrate a decline in caries, though the effectiveness of specific programs is unknown. Chronic gingivitis, a bacterial inflammation of the gums, prefigures chronic peritonitis, which corrodes structural tissue to the point of tooth loss. Cigarette smoking and diabetes mellitus appear to be large factors in the instigation and promotion of peritonitis. Programs aiding the cessation of smoking and improving the general health maintenance of individuals can have a powerful impact on the frequency and severity of the disease. Other oral diseases include oral precancer and cancer, which are greatly affected by the use of tobacco and alcohol. Oral manifestation of HIV/AIDS should be also noted as an important indicator of the disease. The prevention of oral disease proves to be more cost–effective than restorative treatment after the onset of disease. Community mobilization and public policy to combat oral disease, in conjunction with programs instructing preschool and elementary school–age children in proper oral hygiene, are good examples.