Influence of veneering composite composition on the efficacy of fiber-reinforced restorations (FRR)

This study investigated the influence of fiber reinforcement on the flexura l properties of four commercial (Artglass, Belleglass HP, Herculite XRV and Solidex) veneering composites (Series A) and two experimental composites ( Series B&C. This study investigated how the composition of the veneering co mposites influenced the enhancement of strength and modulus produced by fib er reinforcement. The formulation of the experimental composites were varie d by changing the filler load (Series B) or the resin matrix chemistry (Ser ies C to assess the effect these changes would have on the degree of reinfo rcement. In Series A, the commercial veneering composites were reinforced by an Ultr a-High-Molecular-Weight Polyethylene fiber (UHMW-PE/Connect) to evaluate fl exural properties after 24 hours and six months. In Series B, experimental composites with the same organic matrix but with different filler loads (40 % to 80% by weight) were also reinforced by Connect fiber to evaluate flexu ral properties. In Series C, experimental composites (Systems 1-4) with the same filler load (76.5% by weight) but with different organic matrix compo sitions were reinforced by Connect fiber to evaluate flexural properties. F or Series B and C, flexural properties were evaluated after 24 hours water storage. All the samples were prepared in a mold 2 mm x 2 mm x 25 min and stored in distilled water at 37 degreesC until they were ready for flexural testing i n an Instron Universal Testing Machine using a crosshead speed of I mm/minu te. The results showed no significant differences in the flexural strength (FS) between any of the commercial reinforced composites in Series A. The f lexural modulus (FM) of the fiber-reinforced Belleglass HP group was signif icantly higher than for Artglass and Solidex. Water storage for six months had no significant (p >0.05) effect on the flexural strength of three of th e four reinforced veneering composites. The flexural strength for Artglass was significantly reduced (p <0.05) by six-month water storage. In Series B , however, increasing the amount of filler loading improved the flexural mo dulus of the reinforced experimental composite but had no effect on its fle xural strength. In Series C, changing the organic matrix formulation had no affect on flexural strength but affected the flexural modulus of the reinf orced experimental composite.