Global epidemiology of periodontal diseases: an overview

This volume aims to provide a comprehensive evaluation of the distribution of various types of periodontal diseases from each of the world’s five major geographic regions. Epidemiology is the study of the health and disease in populations, as compared to individuals (20). Study of the distribution of human periodontal diseases and their risk factors on a global scale offers a unique investigational model that can provide power and generalization to observations on the periodontium made initially among more limited populations. In assessing causation between periodontal diseases and their suspected etiologic risk factors, it is useful to demonstrate consistency of the relationships in multiple, representative population samples. When diverse study approaches in various populations by different investigators produce similar conclusions on the distribution of periodontal diseases and/or their associations with putative risk factors, then one can be more confident that real phenomenon and/or causal relationships exist (29). Indeed, population-based studies provide external validity to observations obtained from more discrete subject groups, and enable generalization of the conclusions (14). Alternatively, differences in periodontal disease patterns among various population groups can be exploited to uncover previously unidentified risk factors that may not be expressed in all populations. Available population-based periodontal disease data originate from studies encompassing a wide range of objectives, designs and measurement criteria (18). The lack of standardized study design, definition of periodontal disease status, methods for disease detection and measurement, and criteria for subject selection markedly limit interpretation and