Defining a periodontitis case: analysis of a never-treated adult population

The purpose of the present study was to assess the extent to which the three periodontitis case definition systems proposed by van der Velden, Tonetti & Claffey and Page & Eke identify the same cases in a population of never-treated adults with limited tradition for oral hygiene procedures.Based on data on clinical attachment level (CAL), probing pocket depth (PD) and bleeding on probing (BOP) of four sites in all teeth present among 1,130 adult Kenyans we classified the population according to the three case definition systems, and according to the occurrence of the concomitant presence of CAL and BOP at the site level.The case definitions by Tonetti & Claffey and by Page & Eke yielded similar results, which were also quite similar to the results of simply identifying a case of periodontitis as a person having at least one site showing both CAL ≥ 4 mm and BOP.The results indicate that it should be feasible for the periodontal community to reach an agreement over the distinction between a case and a non-case. The classification system proposed by van der Velden is better suited for providing clinicians with a clear image of the case.