Abstract
BACKGROUND: The 2018 classification of periodontal disease characterizes the disease with a multidimensional staging and grading system. The purpose of this multicenter study was to examine variations in periodontitis classification among dental practitioners with different postgraduate educational backgrounds at the University of Maryland School of Dentistry and the Loma Linda University School of Dentistry using the 2018 classification. METHODS: This cross-sectional observational study included two cohorts: dental practitioners with periodontal backgrounds (n(1) = 31) and those with other educational backgrounds (n(2) = 33). The survey instrument contained three periodontitis cases presented with the guideline of the 2018 classification and a questionnaire including closed and open-ended questions. The participants were asked to review each case and to fill out the questionnaire independently. Fisher's exact test was conducted to examine the differences in responses between the two cohorts. Polychoric correlations were calculated to examine the relation between the level of familiarity with the 2018 classification and the accuracy of the classification. RESULTS: The distribution of item responses was significantly different between the two cohorts regarding only one item, grading for Case 1 (p = 0.01). No significant differences in accuracy between the two cohorts were observed except for two items, grading in Case 1 (p = 0.03) and staging in Case 3 (p = 0.04). There were no significant differences in risk factor identification for each case among the two cohorts (p = 1.00, Case 1; p = 0.22, Case 2). Staging in Case 3 ([Formula: see text] = 0.52) and risk factor identification in Case 2 ([Formula: see text]= 0.32) were significantly correlated with familiarity with the 2018 classification. CONCLUSION: A fair level of agreement in periodontitis classification was observed among dental practitioners with different educational backgrounds when the 2018 classification was used. The periodontal cohort showed better agreement levels and partially better accuracy. Risk factor identification for periodontal disease was difficult regardless of the educational background.