Methods: The data were collected from the dental records of 21 prosthodontists in their own dental clinics. 210 patients who had been provided new PRDs and used them more than 3 years were selected. The survival rates of 982 abutment teeth for 319 RPDs were determined by a Kaplan-Meier method. Cox proportional hazard model was used to test the significance of explanatory variables as a predictor of the tooth loss after controlling for the other factors. P-values<0.05 were considered to be statistically significant.
Results: The mean age of patients was 62.6+/-8.2 (SD) years. Survival rates of abutment teeth were 79% in 5 years and 55% in 10 years. Cox proportional hazard model revealed that after controlling for the other factors incisor teeth were 1.96 times more likely to be lost than canine and premolar teeth (95% confidence interval:1.44-2.66). In relation to tooth loss, pulpless teeth were 1.79 times more than vital teeth (95% CI:1.43-2.23); teeth without occulusal contact were 1.52 times more than with contact (95% CI:1.13-2.06); teeth having under 5 teeth in the same jaw were 1.79 times more than over 6 teeth group (95% CI:1.38-2.32); maxillary teeth were 1.55 times more than mandible teeth (95% CI:1.22-1.98).
Conclusion: Among abutment teeth of RPDs, teeth of incisor, pulpless, without occlusal contact, having fewer teeth in the same jaw and maxillary teeth were suggested to be lost more during a long-term follow-up. These results can indicate us the risk factors for abutments loss of the RPDs.