title: Dentin Bonding Testing Using a Mini-interfacial Fracture Toughness Approach.
abstract: Measurement of interfacial fracture toughness (iFT) is considered a more valid method to assess bonding effectiveness as compared with conventional bond strength testing. Common fracture toughness tests are, however, laborious and require a relatively bulky specimen size. This study aimed to evaluate a new simplified and miniaturized iFT (mini-iFT) test. Four dentin adhesives, representing the main adhesive classes, and 1 glass ionomer cement were applied onto flat dentin. Mini-iFT (1.5 × 2.0 × 16 to 18 mm) and microtensile bond strength (µTBS; 1.5 × 1.5 × 16 to 18 mm) specimens were prepared from the same tooth. For the mini-iFT specimens, a single notch was cut at the adhesive-dentin interface with a 150-µm diamond blade under water cooling; the specimens were loaded until failure in a 4-point bending test setup. Finite element analysis was used to analyze stress distribution during mini-iFT testing. The correlation between the mean mini-iFT and µTBS was examined and found to be significant; a strong positive correlation was found (r(2) = 0.94, P = 0.004). Weibull data analysis suggested the mini-iFT to vary less than the µTBS. Both the mini-iFT and the µTBS revealed the same performance order, with the 3-step etch-and-rinse adhesive outperforming the 2-step self-etch and 2-step etch-and-rinse adhesive, followed by the 1-step SE adhesive and, finally, the glass ionomer cement. Scanning electron microscopy failure analysis revealed the adhesive-dentin interface to fail more at the actual interface with the mini-iFT test, while µTBS specimens failed more within dentin and composite. This finding was corroborated by finite element analysis showing stress to concentrate at the interface during mini-iFT loading and crack propagation. In conclusion, the new mini-iFT test appeared more discriminative and valid than the µTBS to assess bonding effectiveness; the latter test nevertheless remains more versatile. Specimen size and workload were alike, making the mini-iFT test a valid alternative for the popular µTBS test.
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven), and Dentistry, University Hospitals Leuven, Leuven, Belgium Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
authors.forename: P
authors.initials: P
authors.lastname: Pongprueksa
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven), and Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: De Munck
authors.affiliation: National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani, Thailand.
authors.forename: K
authors.initials: K
authors.lastname: Karunratanakul
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven), and Dentistry, University Hospitals Leuven, Leuven, Belgium BMGO, Biomechanics Section, Department of Mechanical Engineering, KU Leuven (University of Leuven), Leuven, Belgium.
authors.forename: B C
authors.initials: BC
authors.lastname: Barreto
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven), and Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Van Ende
authors.affiliation: Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
authors.forename: P
authors.initials: P
authors.lastname: Senawongse
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven), and Dentistry, University Hospitals Leuven, Leuven, Belgium bart.vanmeerbeek@med.kuleuven.be.
authors.forename: B
authors.initials: B
authors.lastname: Van Meerbeek
mesh_terms: D000268:Adhesiveness; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D020342:Finite Element Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008422:Materials Testing / Q000379:methods; D008855:Microscopy, Electron, Scanning; D008904:Miniaturization; D018583:Pliability; D015203:Reproducibility of Results; D019279:Resin Cements / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D015040:Zirconium / Q000737:chemistry
chemical_list: C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C439808:Fuji IX GP Fast; D005899:Glass Ionomer Cements; C469607:OptiBond FL; D019279:Resin Cements; C083568:Z100 composite resin; D012822:Silicon Dioxide; C041330:Scotchbond; D015040:Zirconium
keywords: Weibull; adhesive testing; adhesives; bond strength; finite element analysis; micro-tensile