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

Author(s)

de Oliveira Lino, Lucas Fracassi ^[1] ; Machado, Camila Moreira ^[1] ; de Paula, Vitor Guarconi ^[1] ; Vidotti, Hugo Alberto ^[2] ; Coelho, Paulo G. ^[3] ; Benalcazar Jalkh, Ernesto Byron ^[1] ; Pegoraro, Thiago Amadei ^[4] ; Bonfante, Estevam Augusto ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Prosthodont & Periodontol, Bauru Sch Dent, Alameda Octavio Pinheiro Brisolla 9-75, BR-17012901 Bauru, SP - Brazil

^[2] Univ Western Sao Paulo, Dept Prosthodont, Jose Bongiovani St 700, Cidade Univ, BR-19050920 Pres Prudente, SP - Brazil

^[3] NYU, Dept Biomat, Coll Dent, NYU Tandon Sch, Hansjorg Wyss Dept Plast Surg, Langone Med Ctr, Mec, 433 1st Ave, Room 844, New York, NY 10010 - USA

^[4] Univ Sagrado Coracao, Dept Implantol & Prosthodont, Rua Irma Arminda 10-50, BR-17011160 Bauru, SP - Brazil

• Document type: Journal article
• Source: Dental Materials; v. 34, n. 11, p. 1690-1701, NOV 2018.
• Web of Science Citations: 3

Abstract

Objective. To evaluate and compare the outcomes of shear (S) and microtensile (mu T) 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 x 5 x 5 mm) for mu T. 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) mu TC: samples tested in mu T 24 h after bonding); (3) mu TF: samples submitted to mechanical fatigue prior to mu T test, and; (4) mu TT: thermocycling prior to mu T 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 (eta) and Weibull modulus (m) for SC (eta = 6.9 MPa and m = 1.4) compared to mu TC (eta = 20.9 MPa and m = 4.5). Fatigued and thermocycled mu T groups presented significantly reduced characteristic strength (eta = 3.1 MPa and eta = 4.1 MPa, respectively) compared to mu TC. Weibull modulus was significantly reduced only for SC and mu TF groups compared mu TC. 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. (C) 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 12/19078-7 - Development and processing of Al2O3-ZrO2 translucent composite for CAD/CAM monolithic prostheses: the effect of aging on biaxial flexural strength
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 16/18818-8 - Multi-User Equipment approved in grant 2012/19078-7: ElectroPuls E3000 Linear-Torsion All-Electric dynamic test instrument package
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 14/18463-0 - Bond strength between dentin and CAD/CAM fiber-reinforced composite blocks after mechanical fatigue and thermocycling
• Grantee: Lucas Fracassi de Oliveira Lino
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/03072-6 - Experimental 70% Al2O3-30% ZrO2 composites: structural characterization and survival probability before and after aging
• Grantee: Ernesto Byron Benalcazar Jalkh
• Support Opportunities: Scholarships in Brazil - Doctorate