Survival and Complications of Tooth/Implant-supported and Implant-supported FDPs

Objectives: Objective of this retrospective analysis study was to evaluate survival and complications of metal-ceramic and all-ceramic implant-supported fixed dental prostheses (FDPs) and combined tooth/implant-supported FDPs.
Methods: From a prospective clinical long-term study 436 FDPs placed in 334 patients (42.8% men, mean age 61.7years) were selected, including 214 implant-supported FDPs, 66 implant-supported cantilever FDPs and 156 tooth/implant-supported FDPs. Metal-ceramic FDPs were casted with Au-alloys (n=225) or CoCr-alloys (n=35) and combined with full coverage veneers. One additional CoCr FDP was not veneered. All-ceramic FDPs (n=175) were exclusively made with Zirconia frameworks combined with full coverage veneers (n=43), vestibular veneers (n=63) or monolithic design (n=69). The FDPs were predominantly fixed with permanent cements (n=306) or semi-permanent cements (n=119). Kaplan-Meier curves were used to estimate FPD survival and complication rates. Risk factors for the most frequent complications were evaluated with multivariate Cox regression analyses.
Results: During the observation period up to 12.6 years, 17 FDPs failed because of failed implants (n=6), tooth loss (n=5), major chipping (n=5) or abutment loosening (n=1). Probability of survival was 96% after 5 years and 91% after 10 years without significant effect of age, sex, location, support or material. Separate analysis of the frequent complication “chipping” (n=61) revealed that veneering technique (HR=2.8) was a significant risk factor (p=.003). Zirconia FDPs with full coverage veneers demonstrated the highest 5-year chipping rate (39%) compared to metal-ceramic Au-FDPs (18%). Zirconia FDPs with partial veneers or without veneer and CoCr-FDPs showed significantly lower chipping rates (<10%). De-cementation accounted for further 61 complications. Cox regression analysis revealed a risk reducing effect for combined tooth/implant-support (HR=0.34) and permanent cement (HR=0.17). Other variables as location, number of units or framework material had no significant effect.
Conclusions: Tooth/implant-supported FDPs can be recommended because of high survival rates and minimal de-cementation rates.