Tooth-related factors for tooth loss 20 years after active periodontal therapy-A partially prospective study.

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.
(© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)