Stages and Grades of the 2018 AAP/EFP Classification of Periodontitis Vary by the Tooth Type: A 5-year Observational Study

This study was conducted to investigate the relationship between the anatomical differences of the teeth (differences in tooth locations and types) and the degree of progression of periodontitis. We examined whether the stages and grades of periodontitis according to the classification system of the American Academy of Periodontology/European Federation of Periodontology might vary according to the tooth type.Over a period of 5 years, we evaluated the clinical attachment loss, probing depth, tooth loss, and degree of tooth mobility of 99,277 teeth of 1,375 Japanese patients with periodontitis. We calculated the number of teeth in each category according to whether they were classified the teeth into maxillary or mandibular teeth, teeth on the right or left sides, and anterior, premolar or molar teeth for the analyses in this study.Differences in the staging were found between the maxillary and mandibular teeth, and among the anteriors, premolars and molars, whereas almost no differences were found between the right and left sides. Periodontitis progresses rapidly to a significantly greater degree of severity in the maxillary teeth and molar teeth than in the mandibular or other types of teeth.These differences depending on the tooth locations and types need to be considered when classifying the stages of periodontitis according to the new classification system.