A lack of consensus in the measurement methods for and definition of periodontitis.

Clinical question. What are the definitions of periodontitis and the methods used to measure this disease? Review methods. The reviewers searched four electronic databases for human studies with no language restriction up to August 2006. They also examined the reference lists of review articles and textbook chapters to identify additional studies. They tried to identify unpublished studies by searching abstracts and conference proceedings. They assessed the methodological quality of the reviewed studies by using generic criteria (study design, sample selection, confounding and examiner training or calibration of their methodology) and disease-specific factors (measurement methods and definition of periodontitis). Two reviewers selected and evaluated studies independently. They included in their review only the studies that defined periodontitis and indicated how it was measured. They excluded studies that related purely to gingivitis, intervention studies and studies for which prevalence or severity of periodontitis was not a principal outcome. Main results. From 3,472 titles and abstracts, the reviewers identified 104 potentially relevant full-text articles. Of these articles, 15 met the criteria for inclusion in the review. The sample sizes of the studies in the included articles ranged from 185 to 15,302 participants. There was a considerable heterogeneity between the studies in terms of their measurement methods for and definitions of periodontitis. The threshold for a diagnosis of periodontitis when clinical attachment loss (CAL) was the criterion ranged from 2 to 6 millimeters or more, and when probing pocket depth (PPD) was the criterion, the threshold was from 3 to 6 mm or more. Conclusions. This systematic review confirmed the findings of previous literature that studies used diverse measurement methods for and definitions of periodontitis.