Using periodontal staging and grading system as a prognostic factor for future tooth loss: A long-term retrospective study

Background A new classification of periodontal diseases aimed to identify periodontal disease based on a multidimensional staging and grading system has been recently proposed. However, up to date, its prognostic predictive capability has not been investigated. The aim of this study was to assess if parameters included in the new classification were predictive of tooth loss after a long-term follow-up (>10 years) in patients with periodontitis. Methods Patients presented with periodontitis at the University of Michigan between January 1966 and January 2004 were screened and categorized according to the new classification of periodontitis. Number/Reasons of teeth loss in patients who underwent at least one session/year of maintenance during the entire follow-up period were extracted and used to analyze the prognostic capabilities of variables (staging, grading, and Extent) included in the new classification. Results A total number of 292 patients with a mean follow-up of 289.7 +/- 79.6 months were included. 31 (10.6%) patients were classified as Stage 1, 85 (29.1%) as Stage 2, 146 (50%) as Stage 3, and 30 (10.3%) as Stage 4. For grading, 34 (11.7%) were classified as Grade A, 193 (66.1%) as Grade B, and 65 (22.2%) as Grade C. Results of multilevel Cox regression analyses revealed a statistically significant association between stage (HR:3.73 between stage 4 and Stage 1) and grade (HR: 4.83 between grade C and grade A) at baseline and periodontal related tooth loss, whereas no differences were detected for the extent of periodontitis. Conclusion This study provides the initial evidence regarding the predictive ability of the new classification of periodontitis. Patients in either Stage 4 or Grade C showed a significantly higher periodontal-related tooth loss.