To illustrate the variation in prevalence of periodontitis after applying 7 different validated case criteria in participants of the oral part of The Danish Health Examination Survey (DANHES). In addition, to evaluate the unadjusted relation of known risk factors, i.e. age, gender, and smoking to periodontitis when defined differently.
Method:
DANHES is a cross-sectional base-line study carried out in Denmark in 2007-08. In total, 18,065 participated in the general health examination. Of those, 4,402 individuals aged 18-96 years had an oral examination in 2008-09. The periodontal examination was performed in optimal clinical settings and based on half-mouth registration at 6 sites per tooth and included level of gingival margin, probing pocket depth (PPD) and calculation of clinical attachment level (CAL). Prevalence of periodontitis was estimated according to severe periodontitis (Page & Eke 2007), sensitive and specific case definition (Tonetti & Claffey 2005), MeanCAL≥3mm, MeanCAL≥4mm, CAL-tertile definition (Beck et al. 2001), and PPD-CAL definition (Lopez et al. 2002). Data were described by univariate and bivariate analyses.
Results:
Thirty-five were edentulous and another 9 individuals were excluded due to missing data, leaving 4,358 participants for descriptive statistics. Interestingly, the prevalence of periodontitis in this selected population varied between 9.5% and 70.2% among the 7 case criteria. A combination of the 7 definitions resulted in 320 (7.4%) periodontitis cases. For all periodontitis definitions, the case prevalence was higher among older compared to younger individuals, among men compared to women, and among individuals with a history of smoking compared to never-smoking participants.
Conclusion:
Obviously, it is important to consider that there are numerous ways to define a periodontitis case, and dependent on definition the analysis of prevalence shows extensive variation. The choice of case criterion may depend on purpose of the study, but various definitions may be applied to illustrate the differences.