Effect of aging and testing method on bond strength of CAD/CAM fiber-reinforced composite to dentin

Lucas Fracassi de Oliveira Lino, Camila Moreira Machado, Vitor Guarçoni de Paula, Hugo Alberto Vidotti, Paulo G. Coelho, Ernesto Byron Benalcázar Jalkh, Thiago Amadei Pegoraro, Estevam Augusto Bonfante

Research output: Contribution to journalArticlepeer-review


Objectives: To evaluate and compare the outcomes of shear (S) and microtensile (μT) bond strength tests of CAD/CAM fiber-reinforced composite (FRC) to dentin. Aging with either fatigue or thermocycling were conducted for comparison with baseline microtensile group. Methods: CAD/CAM FRC (Trinia, Bicon LLC, Boston, USA) blocks were milled to 3-mm diameter cylinders for shear and to blocks (5 × 5 × 5 mm) for μT. Sixty extracted human molars were flattened to obtain dentin surfaces and randomly divided in four groups (n = 15): (1) SC: samples tested in shear 24 h after bonding; (2) μTC: samples tested in μT 24 h after bonding); (3) μTF: samples submitted to mechanical fatigue prior to μT test, and; (4) μTT: thermocycling prior to μT test. Bonding system was applied onto the FRC material (Cera–Resin Bond, CRB, Shofu Dental, Kyoto, Japan). A conventional three-step adhesive system (All-bond 3, Bisco, Schaumburg, USA) was use with a self-cure resin cement (C&B resin cement, Bisco, Schaumburg, USA). Bond strength tests were conducted at 0.75 mm/min and data analyzed using Weibull distribution (p < 0.05). Results: Weibull contour plots showed a significantly lower characteristic strength (η) and Weibull modulus (m) for SC (η = 6.9 MPa and m = 1.4) compared to μTC (η = 20.9 MPa and m = 4.5). Fatigued and thermocycled μT groups presented significantly reduced characteristic strength (η = 3.1 MPa and η = 4.1 MPa, respectively) compared to μTC. Weibull modulus was significantly reduced only for SC and μTF groups compared μTC. Failure predominantly occurred at the cement/FRC interface. Significance: FRC bonded to dentin samples presented lower Weibull modulus and characteristic bond strength when immediately tested in shear compared to microtensile. Aging through thermocycling or mechanical fatigue significantly reduced the characteristic strength in microtensile testing, with the majority of failures emerging between restoration material and cement interface.

Original languageEnglish (US)
Pages (from-to)1690-1701
Number of pages12
JournalDental Materials
Issue number11
StatePublished - Nov 2018


  • Bonding strength
  • Dentin
  • Dentin bonding

ASJC Scopus subject areas

  • General Materials Science
  • General Dentistry
  • Mechanics of Materials


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