Aim To assess factors contributing to tooth loss 20 years after active periodontal therapy (APT) on tooth level. Materials and Methods After an initial retrospective analysis 10 years after APT, patients were monitored for 10 more years. At clinical re‐evaluation 20 years after APT, tooth‐related factors (tooth type, location, bone loss, furcation involvement, abutment status) and patient‐related factors (gender, smoking, adherence) were investigated. Descriptive statistical analysis and a mixed logistic regression analysis were performed with tooth loss as primary outcome variable. Results The study included 69 patients (42 female/27 male). 39 patients were non‐adherent (56.5%), and 11 were active smokers (15.9%). A total of 198 out of 1611 teeth were lost. Tooth loss was significantly highest (p < .01) in molars (21.1%), multi‐rooted teeth with furcation involvement (23.5%) and abutment teeth (fixed: 27.6%, removable: 36.4%). 37.6% of teeth with initial bone loss >60% were lost during 20 years. Adherent patients showed less frequent tooth loss than non‐adherent patients (OR 0.371; p <  .01). Conclusion Even teeth with an initial bone loss over 60% could be retained in approximately two thirds for 20 years. This should be kept in mind when assigning prognosis and establishing a treatment plan.

Objectives There is little evidence about the effect of different treatment protocols for grade 3 endo-periodontal lesions without root damage in patients with periodontitis according to the new classification of periodontal disease. The aim of this study is to evaluate the impact of endodontic treatment on the achievement of periodontal healing. Materials and methods Teeth with the initial diagnosis endo-periodontal lesion without root damage grade 3, treated with a standardized endodontic treatment protocol, were included in this study. A retrospective analysis was performed to assess the impact on periodontal healing by evaluating probing pocket depth (PPD), clinical attachment gain (CAL), and periapical index score (PAI). Results Nineteen teeth and 13 patients were included. A mean reduction of 3.19 ± 3.41 mm in PPD was recorded. The mean CAL gain was 2.33± 3.75 mm. Five teeth (45.4%) showed an improvement of PAI and were classified as treatment success. Conclusions The results failed to show a highly predictable treatment outcome for endo-periodontal lesion grade 3 without root damage in patients with periodontitis. However, endodontic therapy alone resulted in treatment success for some of the teeth, which would otherwise have had a poor prognosis. Clinical relevance Endo-periodontal lesions can often be challenging for dentists in daily clinical practice. To date, there is not much evidence for practitioners to rely on. Therefore, this study aims to strengthen the evidence for the management and treatment of endo-periodontal lesions. Although the outcome is not highly predictable yet, teeth with the initial diagnosis endo-periodontal lesion without root damage grade 3 can benefit from an endodontic treatment.

Objectives The aim of this study was to develop a prognostic tool to estimate long-term tooth retention in periodontitis patients at the beginning of active periodontal therapy (APT). Material and methods Tooth-related factors (type, location, bone loss (BL), infrabony defects, furcation involvement (FI), abutment status), and patient-related factors (age, gender, smoking, diabetes, plaque control record) were investigated in patients who had completed APT 10 years before. Descriptive analysis was performed, and a generalized linear-mixed model-tree was used to identify predictors for the main outcome variable tooth loss. To evaluate goodness-of-fit, the area under the curve (AUC) was calculated using cross-validation. A bootstrap approach was used to robustly identify risk factors while avoiding overfitting. Results Only a small percentage of teeth was lost during 10 years of supportive periodontal therapy (SPT; 0.15/year/patient). The risk factors abutment function, diabetes, and the risk indicator BL, FI, and age (≤ 61 vs. > 61) were identified to predict tooth loss. The prediction model reached an AUC of 0.77. Conclusion This quantitative prognostic model supports data-driven decision-making while establishing a treatment plan in periodontitis patients. In light of this, the presented prognostic tool may be of supporting value. Clinical relevance In daily clinical practice, a quantitative prognostic tool may support dentists with data-based decision-making. However, it should be stressed that treatment planning is strongly associated with the patient’s wishes and adherence. The tool described here may support establishment of an individual treatment plan for periodontally compromised patients.