Fracture load of provisional fixed partial dentures with long-span fiber-reinforced acrylic resin and thermocycling

Abstract

The purpose of this study was to evaluate the fracture load and fracture pattern of fiber-reinforced long-span acrylic resin provisional fixed partial dentures (FPDs) with different fiber types and reinforcement lengths after thermocycling. Eighty standardized four-unit FPDs of polymethyl methacry-late resin were fabricated on a metal jig and evenly divided into eight groups. The control and comparison groups were unreinforced acrylic specimens and specimens reinforced with 4-mm steel wire, respectively. The six experimental groups comprised acrylic FPDs reinforced with 4-, 18-, and 30-mm glass fiber (FibreKor) or polyethylene fiber (Construct). One-way ANOVA results revealed statistically significant differences between the fracture loads of the experimental and control/comparison groups (P < 0.05). Two-way ANOVA results revealed that among the experimental groups, there were statistically insignificant differences between different reinforced fiber types and lengths (P < 0.05). It is worth noting that increasing the reinforced fiber length was less important for enhancement of fracture load than the location of fiber reinforcement in the long-span acrylic resin FPDs. All samples displayed partial fracturing after thermocycling. The mean fracture loads of the experimental groups were ∼50% higher than those of the control/comparison groups. The results of this study indicate that fiber reinforcement with FibreKor/Construct enhanced the fracture load of long-span acrylic resin provisional FPDs after thermocycling.