Fracture strength of direct surface-retained fixed partial dentures: effect of fiber reinforcement versus the use of particulate filler composites only.

This study compared the fracture strengths and analyzed the failure types of direct, surface-retained, anterior fixed-partial-dentures (FPD), reinforced with four types of fiber-reinforced composites (FRC) versus non-fiber-reinforced FPDs made of three particulate filler composites (PFC). To this end, surface-retained anterior FPDs (N = 70, 10 per group) were prepared and divided into seven experimental groups, where Group 1: FRC1 (everStick) + PFC1 (Clearfil Photo Posterior); Group 2: FRC2 (BR 100) + PFC1; Group 3: FRC3 (Interling) + PFC1; Group 4: FRC4 (Ribbond) + PFC1; Group 5: PFC1 only; Group 6: PFC2 only (Sinfony); and Group 7: PFC3 only (Estenia). Fracture strength test was performed after water storage at 37 degrees C for three days (universal testing machine, 1 mm/min). No significant differences were found among the four FRC types veneered with PFC1 (1490 +/- 548--1951 +/- 335 N) (p < 0.05) (ANOVA, Tukey's test). Among all the experimental groups, PFC1 presented a significantly higher mean value (2061 +/- 270 N) than PFC2 (1340 +/- 395 N) (p < 0.05) and all the other FRC-reinforced groups (p < 0.05). Complete pontic fracture was 100% and 70% for PFC2 and PFC3 respectively.