Effect of two methods of reinforcement on the fracture strength of interim fixed partial dentures

This study assessed the efficiency of reinforcing provisional restorations by adding a fine gauze metallic mesh or polyethylene fibers between the abutments spanning the pontic length.

Forty-five resin fixed partial dentures (FPDs) were constructed using three provisional resins. The three resin groups were further divided into three subgroups depending on their reinforcement. Specimens were loaded compressively, and the load required to fracture the specimens was recorded in Newtons. Data were presented as means and standard deviation values. A regression model with two-way ANOVA was used in testing significance. Duncan's post hoc test was used for pairwise comparison (p < or = 0.05).

Duralay resin and Duralay fiber-reinforced restorations showed the highest fracture-resistance values, followed by Protemp and Snap, which showed statistically similar values. The three mesh-reinforced resin restoration materials showed no statistically significant difference between their fracture resistance values. Reinforcement did not alter the fracture resistance of Duralay and Protemp resin subgroups, but significantly increased that of Snap, equalizing it with the other resins. The three resin materials had similar moduli. Significant alterations occurred after fiber reinforcement. Results showed that fiber-reinforced Duralay resin showed the highest modulus values, while no statistical difference was found between the moduli of fiber-reinforced Protemp and Snap. Regarding the mesh-reinforced groups, Duralay had the highest modulus followed by Protemp and Snap. Reinforcements altered the modulus values of Duralay resin only. Mesh-reinforced Duralay resin showed the highest mean modulus, but no statistically significant difference was apparent between fiber-reinforced and control groups. As for Protemp and Snap resin subgroups, their moduli remained unchanged by reinforcements.

Initially, Duralay resin had higher fracture resistance values than Protemp II and Snap. Fiber and mesh reinforcements increased the fracture resistance of Snap. No statistically significant difference was evident among the fracture resistances of the three mesh-reinforced resin FPD restorations. The three resins had similar moduli. Fiber and mesh reinforcement increased the modulus of Duralay resin but did not change that of Protemp and Snap. Fiber and metal mesh reinforcements may alter the fracture strength and modulus of some, but not all, provisional resins.