Long-term tooth loss in periodontally compromised but treated patients according to the type of prosthodontic treatment. A retrospective study.

If prosthodontic treatment is considered after periodontal therapy, the questions arise i) does prosthodontic treatment affect the treatment outcome of the dentition in general and ii) which type of prosthesis is related to best treatment outcome of abutment teeth? Our goal was to compare long-term tooth loss after comprehensive periodontal therapy in patients with or without prosthodontic treatment. Ninety patients' charts with a total of 1937 teeth who had received comprehensive periodontal treatment 5-17 years ago by the same periodontist were retrospectively evaluated. Sixty-five patients received fixed dental prostheses (FDP; n = 29) and/or removable partial dentures anchored with clips (RPDC; n = 25) or double crowns (RPDD; n = 25). Twenty-five patients were also periodontally compromised but treated without prosthodontic treatment and served as a control group. A total of 317 teeth and 70 abutment teeth were lost during 9.7 ± 4.1 years of observation. Thereof, 273 teeth and 48 abutment teeth were lost due to periodontal reasons. Mean tooth loss amounted to 1.2 ± 1.5 (controls) and 4.4 ± 3.4 (partial dentures). Abutment tooth loss was 0.4 ± 1.1 (FDP), 1.0 ± 1.2 (RPDC) and 1.3 ± 1.0 (RPDD). Poisson regressions identified prosthodontic treatment, age, socio-economic status, diabetes mellitus, mean initial bone loss and aggressive periodontitis as factors significantly contributing to tooth loss. Age, diabetes and non-compliance contributed to abutment tooth loss. Not considering biomechanical factors, patients with prosthodontic reconstructions under long-term supportive periodontal therapy were at higher risk for further tooth loss than patients without prostheses. Not only the type of partial denture but also the patient-related risk factors were associated with abutment tooth loss.