Epidemiology of Dental Caries
Introduction
An important function of the World Health Organization (WHO) Oral Health Unit is the collection and analysis of global epidemiologic data on oral diseases, recorded in national, computer-aided studies. Goals for the level of oral health status are set and revised at certain intervals. Because epidemiologic studies measure dental caries in groups or populations, some care must be taken to ensure that the same diagnostic criteria are applied to each individual examined.
Dental caries presents interesting challenges for epidemiologists. For example, the signs of the disease (lesions) may be found on several sites and/or several teeth in the individual and frequently vary in severity. Carious lesions exhibit a broad spectrum of clinical features, depending on how far destruction has progressed on a particular surface. Early demineralization may be detected only with the aid of sophisticated techniques, such as radiography, or after careful cleaning and drying and meticulous examination of the surface. In the more advanced lesion, cavitation is readily
detected. At the intermediate stages, the broad range of clinical signs represent past or current carious attack.
For the results of a particular study to be meaningful, the researchers must establish certain criteria:
1. To fulfill the purpose of the investigation.
2. To allow consistency in application by the examiner over the period of the study (reproducibility).
3. To allow consistency between examiners (if more than one is involved).
4. To establish external validity (ie, measure what they are supposed to measure).
5. To provide a pathobiologic rationale (ie, actually reflect the disease).
There is no gold standard for caries in epidemiologic studies. The most important determinant should be the purpose of the study.