title: Apparent interfacial fracture toughness of resin/ceramic systems.
abstract: We suggest that the apparent interfacial fracture toughness (K(A)) may be estimated by fracture mechanics and fractography. This study tested the hypothesis that the K(A) of the adhesion zone of resin/ceramic systems is affected by the ceramic microstructure. Lithia disilicate-based (Empress2-E2) and leucite-based (Empress-E1) ceramics were surface-treated with hydrofluoric acid (HF) and/or silane (S), followed by an adhesive resin. Microtensile test specimens (n = 30; area of 1 +/- 0.01 mm(2)) were indented (9.8 N) at the interface and loaded to failure in tension. We used tensile strength (sigma) and the critical crack size (c) to calculate K(A) (K(A) = Ysigmac(1/2)) (Y = 1.65). ANOVA and Weibull analyses were used for statistical analyses. Mean K(A) (MPa.m(1/2)) values were: (E1HF) 0.26 +/- 0.06; (E1S) 0.23 +/- 0.06; (E1HFS) 0.30 +/- 0.06; (E2HF) 0.31 +/- 0.06; (E2S) 0.13 +/- 0.05; and (E2HFS) 0.41 +/- 0.07. All fractures originated from indentation sites. Estimation of interfacial toughness was feasible by fracture mechanics and fractography. The K(A) for the systems tested was affected by the ceramic microstructure and surface treatment.
authors.affiliation: School of Dentistry, The University of Passo Fundo, PO Box 611, Passo Fundo, RS, 99001-970, Brazil. dbona@upf.br
authors.forename: A
authors.initials: A
authors.lastname: Della Bona
authors.forename: K J
authors.initials: KJ
authors.lastname: Anusavice
authors.forename: J J
authors.initials: JJ
authors.lastname: Mecholsky
mesh_terms: D000134:Acid Etching, Dental; D000538:Aluminum Silicates / Q000737:chemistry; D000704:Analysis of Variance; D003188:Composite Resins; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis; D004548:Elasticity; D006244:Hardness; D016014:Linear Models; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D018583:Pliability; D011897:Random Allocation; D019279:Resin Cements; D012821:Silanes; D012822:Silicon Dioxide; D013499:Surface Properties; D016019:Survival Analysis; D013718:Tensile Strength; D015040:Zirconium
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; C118557:Empress 2; C075815:IPS-Empress ceramic; D018020:Lithium Compounds; D019279:Resin Cements; D012821:Silanes; C083568:Z100 composite resin; D003776:Dental Porcelain; D012822:Silicon Dioxide; D015040:Zirconium