The relationship between periodontal diagnosis and prognosis and the survival of prosthodontic abutments: a retrospective study.

OBJECTIVE: To examine the relationship between periodontal diagnosis and prognosis and survival of prosthodontic abutments over time. METHOD AND MATERIALS: The study consisted of 70 randomly selected patients with either fixed or removable partial dentures delivered by dental students. Age, gender, ethnicity, pertinent medical history, smoking status, procedure performed, abutment tooth number, year of prosthesis delivery, year of most recent periodontal examination, year of tooth loss, periodontal diagnosis and prognosis, date of prosthesis delivery, and most recent periodontal examination were extracted from dental charts. Statistical analyses included chi-square, Kaplan-Meier, and Cox proportional hazards models. RESULTS: A total of 16 of 226 abutment teeth (7.1%) were lost. A total of 88.6% of subjects lost no abutment teeth during the study, while 15.7% lost at least 1 tooth. Analysis showed a cumulative 13.8-year survival rate of 66.0% (SE = +/- 0.10). Tooth-specific periodontal prognosis was a significant predictor of tooth loss. The data showed a 3.05-fold increased risk for tooth loss with removable partial denture abutments compared to fixed partial denture abutments. Abutment teeth with an initial specific prognosis of "good" had a 9.3-fold lower risk of loss than teeth with any other specific prognosis. CONCLUSIONS: Teeth with a periodontal prognosis other than good and those used as removable partial denture abutments had an increased risk of tooth loss. Periodontal diagnosis, overall prognosis (prognosis for the entire dentition), gender, ethnicity, smoking status, and diabetes were not significantly associated with abutment tooth loss over time.