Proposing a Novel, Three-level Definition of Periodontitis using Probing Depth, Clinical Attachment Loss and Bleeding on Probing: Analysis of a Rural Chinese Population.

Objective: To propose a novel, three-level (severe, moderate, mild) case definition using probing depth (PD), clinical attachment loss (CAL) and bleeding on probing (BOP) for epidemiologic studies on periodontitis.

Methods: Case definitions (DEF) 1-30 with PD, CAL and BOP were made. Based on data from epidemiologic research in Chengde (Hebei Province, China) in 1992, prevalence of periodontitis by DEF1-30 was calculated and compared with a reference (definitions by Centers for Disease Control and Prevention/American Academy of Periodontology in 2012).