Epidemiology is the foundation upon which governments and local authorities plan preventive measures for future generations, including oral health, such as the fluoridation of water and how many dentists will need to be trained in 20 or 30 years time to meet demand. The oral health educator (OHE) needs to know how dental surveys are used in epidemiology, as well as indices, which are used to measure data in populations and individuals. Basic Guide to Oral Health Education and Promotion, Second Edition. Ann Felton, Alison Chapman