Background: Accurate classification of periodontal conditions is crucial for gathering epidemiological data, which in turn guides public health strategies and treatment approaches. The American Academy of Periodontology and the European Federation of Periodontology (AAP/EFP) introduced a new classification system for periodontal diseases; however, its application in population-based studies remains under investigation. This study aims to compare the prevalence of periodontitis as determined by the AAP/EFP classification and the Centers for Disease Control and Prevention/American Academy of Periodontology (CDC/AAP) classification system. Furthermore, it evaluates the accuracy of the novel AAP/EFP classification system against the established CDC/AAP case definition, specifically for epidemiological research within diverse populations.
Methods: This research utilized epidemiological data from two distinct cross-sectional studies. The first study was population-based and focused on Chilean adults (n=1,456) within the 35-44 and 65-74 age ranges. The second dataset comprised a sample of adolescents (n=1,070) aged 15-19 years from five Latin American countries: Argentina, Chile, Colombia, Ecuador, and Uruguay. In both studies, all participants underwent comprehensive, full-mouth periodontal examinations conducted by rigorously calibrated examiners to ensure data consistency and reliability. The collected epidemiological datasets were then meticulously analyzed and categorized according to both the AAP/EFP and the CDC/AAP case definitions of periodontitis. To rigorously assess the accuracy of the AAP/EFP definition, a statistical evaluation was performed. This involved calculating key metrics including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the area under the receiver operating characteristic (ROC) curve. The CDC/AAP case definition served as the reference standard against which the AAP/EFP classification’s accuracy was measured. This methodological approach allowed for a direct and quantitative comparison of the two classification systems in diverse age groups and populations.
Results: Applying the AAP/EFP classification to adolescent data revealed a periodontitis prevalence of 75.6%. Within this group, the majority were classified as Stage I (39.2%) or Stage II (28.2) periodontitis. In contrast, the CDC/AAP classification indicated a significantly lower periodontitis prevalence in adolescents, at 27.2%. According to the CDC/AAP criteria, moderate periodontitis was the most prevalent form (15.3%), followed by mild periodontitis (11.4%). When evaluating the AAP/EFP system’s performance against the CDC/AAP standard in adolescents, high sensitivity was observed for moderate (95.7%) and severe periodontitis (100%). Specificity ranged from moderate (75%) to high (92%) for moderate and severe periodontitis, respectively. The PPV was 41.6% for moderate and 5.7% for severe periodontitis, while the NPV was consistently high across both categories (moderate = 99%; severe = 100%). The Area Under the Curve (AUC) was 0.91 (95% CI = 0.89-0.93), indicating good discriminatory ability of the AAP/EFP classification in adolescents when compared to the CDC/AAP.
In adults, the AAP/EFP classification indicated a very high periodontitis prevalence of 99%. The predominant classification was Stage IV (81.3%), followed by Stage III (12.8%). Using the CDC/AAP classification, the periodontitis prevalence in adults was notably lower at 88.3%. Similar to adolescents under the CDC/AAP system, moderate periodontitis was the most common form in adults (57.2%), followed by severe periodontitis (29.7%). In adults, the AAP/EFP classification demonstrated high sensitivity for both moderate (99.7%) and severe periodontitis (100%). However, it exhibited low specificity for both moderate (6.8%) and severe periodontitis (8.3%) in this age group. The PPV was 88.7% for moderate and 31.7% for severe periodontitis, with a high NPV in both categories (moderate = 76.5%; severe = 100%). The AUC in adults was 0.57 (95% CI = 0.53-0.62), suggesting a weaker discriminatory ability of the AAP/EFP classification in adults with a high underlying prevalence of periodontitis when compared to the CDC/AAP.
Conclusions: This study highlights a significant discrepancy in periodontitis prevalence depending on whether the AAP/EFP or CDC/AAP classification is employed when analyzing epidemiological data. Defining the comparison between these two systems reveals that the 2017 AAP/EFP classification system exhibits strong performance in identifying periodontitis in adolescents when benchmarked against the CDC/AAP case definition. However, the AAP/EFP system appears to be less accurate in adult populations characterized by a high prevalence of periodontitis. These findings emphasize the importance of considering the chosen classification system when interpreting epidemiological data and formulating public health strategies for periodontal disease. Further research is needed to fully understand the implications of these classification differences across various populations and clinical settings.
