[Data collection and processing considerations in epidemiological studies using the 2018 Case Definition of...

The classification system for periodontal diseases proposed by the European Federation of Periodontology (EFP) and the American Academy of Periodontology (AAP) in 2018 provides a standardized framework for the diagnosis and classification of periodontitis (the 2018 new classification of periodontal diseases). However, its application in epidemiological studies still faces numerous challenges. In 2024, to address these issues, the new framework for the application of 2018 periodontal status classification scheme to epidemiological survey data (the ACES framework) was formally introduced to accommodate the practical needs for epidemiological investigations. This paper systematically outlines the key points for the standardized application of new classifications in epidemiological studies, focusing on four aspects: case diagnosis, staging, extent and grading description. In terms of case diagnosis, it emphasizes the need to report edentulous and non-classified cases, clarifies the threshold for detectable interproximal clinical attachment loss (CAL), and standardizes the diagnosis of gingivitis. Regarding staging, it provides detailed guidelines for the standardized use of parameters such as CAL, probing depth, furcation involvement, as well as the standardization of data recording for tooth loss due to periodontitis and methods for calculating opposing pairs. For extent description, it specifies the definitions and calculation methods for generalized and localized periodontitis. Regarding grading, this paper highlights the difference between direct and indirect methods for grading assignment. This paper provides a reference for clinicians and researchers on the proper implementation of the new classification in epidemiological studies, enhancing the comparability of results across different studies and promoting the standardized epidemiological research in periodontology.