Fatigue strength and Weibull characteristics of fiber-reinforced inlay-retained resin-bonded fixed dental prosthesis: could bulk-fill composites substitute hybrid resin composite?

Abstract

This study evaluated the load-bearing capacity of fiber-reinforced composite (FRC) direct inlay-retained resin-bonded fixed dental prosthesis (RBFDP) made of bulk-fill or conventional hybrid resin – composites after cyclic loading. Sound human teeth (N = 50) were embedded in acrylic until cemento-enamel junction (CEJ) and randomly divided into five experimental groups to receive RBFDPs: (a) Sonic Fill (SF-KaVo and Kerr Dental), (b) Venus Bulk Fill (VB-Kulzer), (c) Quixfill (QF-Dentsply DeTrey), (d) Tetric EvoCeram Bulk Fill (TE-Ivoclar Vivadent), and (e) Clearfil Photo Posterior (CP-Kuraray). All RBFDPs were reinforced with E-glass fiber (everStick). While premolar pontics were build up incrementally in group CP, in other groups resin composites were applied bulk. RBFDPs were subjected to cyclic loading for 1.2 × 106 cycles in the water at intervals of 60 s between 5 °C and 55 °C. Initial (Finitial) and maximal (Fmax) load-bearing capacity (Newton) of the RBFDPs were measured in the Universal Testing Machine (1 mm/min). Data were analyzed using two-way ANOVA and Tukey’s tests (α = 0.05). Significant difference was found between the groups for Finitial (142 ± 84 to 284 ± 198) and Fmax (408 ± 65 to 688 ± 306) (p<.05). All bulk-fill resins (SF, VB, QF, and TE) did not show significant difference to conventional resin composite (CP) in terms of Finitial and Fmax values (p>.05). Weibull distribution of Finitial values (1.63–2.03) was lower than those of Fmax shape values (2.05–8.39) where TE showed the highest results. CP group showed more repairable failures. Bulk-fill composites could be an alternative to conventional hybrid resin composites in the fabrication of direct FRC RBFDPs.