Measuring periodontitis in population studies: A literature review

Case definitions used to identify periodontitis significantly affect the prevalence and risk estimates from population studies. A plethora of definitions has been employed by researchers since the 1940s. The variation in disease definitions affects the comparability and validity of the estimates. This study aimed to review case definitions of periodontitis in prevalence and risk population studies. PubMed and MedIine were searched for the following keywords: "Periodontitis" AND "cross sectional/case control/ epidemiology". Studies were selected and reviewed. We found that there is a variety of case definitions being employed in prevalence and risk factor studies. Starting with the index systems, the definitions have been influenced by our understanding of the pathogenesis of the disease. There is a need for a uniform case definition for prevalence surveys and population-specific definitions for association studies.