Effect of implant type on the stability of cantilever fixed dental prostheses: An in vitro study

Abstract Objectives To simulate the replacement of a premolar with an implant‐supported cantilever fixed dental prosthesis (ICFDP) and how the fracture load is affected by implant type, positioning within the zirconia blank, and aging protocol. Materials and Methods Seventy‐two ICFDPs were designed either within the enamel‐ or dentin layer of a 4Y‐PSZ blank for bone‐level and tissue‐level titanium‐zirconium implants. Fracture load was obtained on the cantilever at baseline (no aging) or after aging in a chewing simulator with the load applied within the implant axis (axial aging) or on the cantilever (12 groups with n = 6). A three‐way ANOVA was applied ( α = .05). Results A three‐way ANOVA revealed a significant effect on fracture load values of implant type ( p = .006) and aging ( p < .001) but not for the position within the zirconia blank ( p = .847). Fracture load values significantly increased from baseline bone level (608 ± 118 N) and tissue level (880 ± 293 N) when the implants were aged axially, with higher values for tissue level (1065 ± 182 N) than bone level (797 ± 113 N) ( p < .001). However, when the force was applied to the cantilever, fracture load values decreased significantly for tissue‐level (493 ± 70 N), while values for bone‐level implants remained stable (690 ± 135 N). Conclusions For ICFDPs, the use of bone‐level implants is reasonable as catastrophic failures are likely to be restricted to the restoration, whereas with tissue‐level implants, the transmucosal portion of the implant is susceptible to deformation, making repair more difficult.