Abstract
Case definitions and criteria of periodontal diseases are not yet consistent worldwide. This can affect the accuracy of any comparison made between two studies. This study determines which are the most common chronic periodontitis case definitions as well as confounding variables that have been reported worldwide in periodontal literature. A systematic assessment on periodontal disease classification and confounders was conducted using all publications in MEDLINE, EMBASE, SCOPUS, and Google Scholar between 1965 and October 2017. Screening of eligible studies and data extraction were conducted in duplicate and independently by two reviewers. The search protocol produced 4,218 articles. Out of these, 492 potentially relevant articles were selected for review. Only 351 studies fulfilled the selection criteria. Combination of probing depth and clinical attachment loss was the most common chronic periodontitis case definitions used (121, studies, 34.5%). CPI/CPITN was the most common classification used. Age was the most common confounder studied in periodontal research (303 studies, 86.3%), followed by gender (268 studies, 76.4%) and race (138 studies, 39.3%). Albumin and creatinine were the least common variables studied (1 or 2 studies each). Different case definitions affect the prevalence and treatment consequences of periodontitis. We need to standardize periodontitis case definitions worldwide to avoid difficulties in case diagnosis and prognosis. Further studies need to be done to assess the association between periodontitis and several potential confounders.