Methods: The study sample was composed of 623 women and 377 men. Mean age at the beginning of the study was 58.3 years (from 56.3 to 61.3). The total numbers of Fixed Dental Prostheses (FDPs) were 2234 bridges and 3546 crowns. The total number of abutments was 8014. Patients with normal or reduced periodontal tissue support were included in the study. FDPs with end abutment teeth and cross-arch FDPs were included. Panoramic x-rays were taken immediately after cementation of the FDPs. Clinical records were kept during the follow-up period. All patients were non-smokers or non-diabetic at the beginning of the treatment. Recalls were done during one year, 15 years after the treatment, until all patients had been clinically examined (visual, tactile) and new panoramic x-rays taken. Survival rate of the abutment tooth and/or its FDP (presence of the tooth and FDP in place) and pulp vitality of the abutment were expressed in percentages. We applied the chi-square statistic to compare caries experience in abutment vs. non-abutment teeth and vital vs. non-vital abutments' survival rates.
Results: The survival rate of the abutment teeth was 95.3 %. For the FDP, it was 93.8%. Vital teeth with non-necrotic complications were 96.7 %. Abutment teeth free of caries were 97.9 %. Caries in non-abutment vs. abutment teeth was p = 0.004. Non-vital/vital abutment survival rate was p = 0.005.
Conclusions: Abutment teeth have no greater caries risk compared with non-abutment teeth. Non-vital abutments have a significantly worse survival rate.