Longevity of teeth in patients susceptible to periodontitis: Clinical outcomes and risk factors associated with tooth loss after active therapy and 30 years of supportive periodontal care

Aim: (i) To evaluate the efficacy of active periodontal therapy supplemented by supportive periodontal care (SPC) in retaining dentition during a 30-year follow-up period in patients susceptible to periodontitis, and (ii) to assess the prognostic factors associated with tooth loss.Materials and Methods: One-hundred and fifty-four patients with periodontitis, retrospectively classified as stage I-IV and grade B-C periodontitis, treated between 1984 and 1986 in a private practice, were enrolled in this study. After periodontal assessment, patients received non-surgical treatment followed by surgical periodontal therapy, orthodontic treatment, and tooth-splinting, where appropriate. SPC consisted of a strict recall programme every 3-6 months over a 30-year period. Recurrences were treated either with subgingival root planing or flap surgery. Dental and periodontal variables were measured at baseline (T0), end of active therapy (T1), and after 25 (T2) and 30 (T3) years. Generalized mixed models were analysed to assess the prognostic factors associated with and survival analyses for tooth loss.Results: Data on 154 patients (4083 teeth) were available at baseline (T0). Teeth considered unworthy of treatment were extracted during active therapy (160, 3.9%) and at re-assessment (13, 0.3%; T1). After 25 years of SPC, 140 teeth out of 3910 in 154 patients (3.6%) were lost (24 in 18 patients for periodontal reasons). Between 25 and 30 years, 20 patients (482 teeth) dropped out, and 61 teeth (2%) were lost (15 in 14 patients for periodontal reasons). Overall, 201 teeth (5.1%) were lost (39 for periodontal reasons) in 30 years of SPC. Generalized mixed models showed that stage III or stage IV periodontitis was associated with greater tooth loss during SPC compared to stage I or stage II (OR = 2.10; p = .048). Generalized periodontitis showed a statistically significant OR = 3.24 (p = .016) compared to the localized one. In SPC (T1-T3), age (p = .011), gender (male; p = .038), molar teeth (p = < .001), T0 and T1 pocket depth (p = < .001), tooth mobility grades 2 (p = .018) and 3 (p = .050), T0 and T1 bone loss (p = < .001), and presence of a root canal treatment (p = < .001) and a crown (p = .009) were statistically significantly associated with tooth loss.Conclusion: (i) Periodontal therapy and a stringent SPC are effective in maintaining most of the teeth in patients with moderate/advanced periodontitis for 30 years, and (ii) age, gender, molar teeth, pocket depth, bone loss, and the presence of a root canal treatment and a crown are prognostic factors associated with tooth loss.