Rotational fatigue-resistance of two-unit Cantilever Resin-Bonded Fixed Partial Dentures

Objectives: The aim of this study was to evaluate in vitro the influence of fibre-reinforcement and luting cement on the resistance to peel loading and fatigue loading of cantilever resin-bonded fixed partial dentures (RBFPDs). Methods: Beams (1mm thick, 2mm wide, and 25mm long) made of particulate filler composite (PFC) Filtek Z100 (3M Espe) or fibre-reinforced composite (FRC) Everstick C&B  (Sticktech Ltd) simulating two-unit cantilever RBFPDs were luted with Panavia F 2.0, (Kuraray) and RelyX ARC (3M Espe) to the enamel of flat ground bovine teeth. The fatigue resistance was investigated with a newly opened package of fibres (new FRC) and with fibres which were stored at 4ºC in air for 6 month in the dark (aged FRC). Fracture resistance (n=8) was obtained in a universal testing machine. Fatigue testing (n=15) was performed by subjecting the specimens to a rotating cantilever beam test (10⁴cycle, 1.2Hz) according the ‘staircase' approach. Results:  ANOVA revealed that fibre-reinforcement and luting cement had significant effect (P<0.05) on fracture and fatigue resistance. Luting cement had no statistical significant effect (P>0.05) on fracture and fatigue resistance of FRC beams. The fatigue resistance of the new FRCs was significantly higher than the aged FRCs.

Conclusion: PFC beams showed highest fracture and fatigue resistance when low E-modulus resin luting cement was used. It was concluded that highest fracture resistance, fatigue resistance were obtained with FRC beams, but it is recommend to use a newly opened package.