Tooth Loss During Supportive Periodontal Care (SPC): A Three Decades Retrospective Study in a University Setting.

AIM: This retrospective cohort study evaluate tooth loss and predictors during exceptionally long term supportive periodontal care (SPC), focusing on residual disease severity at SPC initiation.

MATERIALS AND

METHODS

Seventy patients maintained under SPC for > 30 years were analysed using negative binomial regression (log[SPC-duration] offset) and Cox proportional hazards models (clustered by patient).

RESULTS

Over a mean SPC duration of 36.1 ± 3.0 [30-43] years, 63 patients lost 322 teeth (4.6 ± 4.2 per patient; 0.13 ± 0.12 per patient-year). Despite advanced baseline disease (stage III/IV: 97%), 35-year molar survival was 77% for FI 0 versus 51% for FI II-III. Tooth loss rate was significantly associated with PPD ≥ 6 mm (IRR 1.012; 95% CI 1.003-1.021; p = 0.009) and molar FI II-III (IRR 1.178; 95% CI 1.050-1.321; p = 0.005). A tooth-level Cox model confirmed elevated hazard for PPD ≥ 6 mm (HR 4.02; 95% CI 2.10-7.69) and FI II-III (HR 2.87; 95% CI 1.61-5.11). However, predictive accuracy was modest (PPV 36%-55%), indicating these markers reflect population-level risk rather than individual prognosis.

CONCLUSION

Tooth loss remained low over > 30 years of SPC even for molars with advanced FI, while residual disease severity modulated this risk. Given strong survivorship bias (3.3% of eligible patients), generalisability beyond university-based specialist care is limited.