# Long-Term Survival of Mandibular Incisors with Severe Periodontal Breakdown: Mean Follow-Up of 18 Years

## TL;DR

This study shows that with proper treatment and care, severely damaged lower front teeth can survive for over 18 years.

## Contribution

The study provides long-term survival data for mandibular incisors with severe periodontal breakdown over a 32-year period.

## Key findings

- After 20 years, the survival probability of mandibular incisors was 78%.
- Effective survival probability after 20 years was 89%.
- Patient compliance significantly influenced long-term survival of the teeth.

## Abstract

Background: This retrospective study assessed long-term survival outcomes of severely periodontally compromised mandibular incisors (≥50% bone loss) following initial periodontal treatment and a structured recall protocol. Methods: Ninety-three patients with ≥50% bone loss in all mandibular incisors were treated in a private practice over a 32-year period by the same periodontist. Following initial treatment, patients were assigned 6- or 12-month recall intervals based on response and motivation. The baseline was set after subgingival debridement (visit 3). Last follow-up visit (LFV) in this study was defined as follows: the last control visit of the patients done by the periodontist. ‘Survival’ was divided into 3 groups: complete survival (CS), all incisors were still present, and partial survival (PS), one or two incisor(s) were lost. Total failure (TF) involved instances in which all incisors were lost. Effective survival was monitored when an extracted tooth was repositioned and stabilized with a splint, ensuring preservation of function. Only 9.7% of patients needed a mandibular incisal splint. For reasons of consistency the CPITN was used. Statistical analysis was performed in R. The significance level was set at α = 0.05. Event-free patients can be considered as uninformative censoring, all with the same probability of risk, as they all were still in follow-up at the time of informed consent approval. Results: A total of 93 patients were included in the study. The mean follow-up was 17.7 years. At the last visit, 79.6% of patients retained all incisors, with an effective survival rate of 89.2%. Regarding the survival probability over time, after 15 years, it is 91% (95% CI: 0.86–0.98), and after 20 years, it is 78% (95% CI: 0.69–0.90). The effective survival probability over time after 15 years was 95% (95% CI: 0.91–1.0), and after 20 years, it was 89% (95% CI: 0.81–0.98). Compliance significantly influenced survival (p = 0.007), whereas the number of occluding units did not (p = 0.226). The total amount of teeth lost during the entire follow-up period showed a statistically significant difference compared to survival (p < 0.001). The general periodontal health of the patient population presented a shift from CPITN 3 to the 0–2 group. Conclusions: Severely compromised mandibular incisors demonstrate high long-term survival rates with appropriate therapy. After 20 years the survival probability was 78%, and the effective survival probability, 89%, underscoring the critical role of lifelong periodontal care. Mandibular incisor preservation over long-term follow-up is highly achievable.