Fracture strength of fiber-reinforced surface-retained anterior cantilever restorations

Purpose: This study compared the fracture strength of direct anterior cantilever fiber-reinforced composite (FRC) fixed partial dentures (FPD) reinforced with 3 types of E-glass fibers preimpregnated with either urethane tetramethacrylate, bisphenol glycidylmethacrylate/polymethyl methacrylate, or bisphenol glycidylmethacrylate monomers and 1 ultrahigh molecular weight polyethylene fiber. Failure types were also evaluated. Materials and Methods: A total of 40 caries-free, human maxillary central incisors (n = 10 per group) received surface-retained direct cantilever restoration (1 pontic) after etching and application of bonding agent. Four FRC materials were used (FRC1 = EverStick; FRC2 = BR-100; FRC3 = Interling; FRC4 Ribbond), and pontics were built up using 1 particulate filler composite (Clearfil Photo Posterior). After the fracture test, failure types were analyzed. Results: No significant difference was found between the 4 FRC types veneered with particulate filler composite (893 +/- 459 N to 1326 +/- 391 N) (P = .1278). Complete pontic fracture at the connector area was most prominent for FRC4 (90%), followed by FRC3 (70%). Only FRC2 (10%) showed some fiber fractures, with half of the fiber remaining attached on the enamel surface of the abutment. Conclusion: The fracture strengths of cantilever FPDs made of 4 FRC materials with different monomer matrices and architectures, veneered with particulate filler composite, did not show significant differences. However, failure behavior varied between groups