Periodontal treatment and maintenance of molars affected with severe periodontitis (DPSI = 4): An up to 27-year retrospective study in a private practice.

Objective: This retrospective study aimed to evaluate the long-term response of molars affected with severe periodontitis to periodontal treatment, to analyze the differences in response between molars with and without furcation involvement (FI) and to reevaluate the usefulness of the existing classification of FI in determining the prognosis.

Method And Materials: A total of 402 patients from a single private practice were included. The observation period was 27 years (mean 16.