Interfacial fracture of dentin adhesively bonded to quartz-fiber reinforced composite

The paper presents the results of an experimental study of interfacial failure in a multilayered structure consisting of a dentin/resin cement/quartz-fiber reinforced composite (FRC). Slices of dentin close to the pulp chamber were sandwiched by two half-circle discs made of a quartz-fiber reinforced composite, bonded with bonding agent (All-bond 2, BISCO, Schaumburg) and resin cement (Duo-link. BISCO, Schaumburg) to make Brazil-nut sandwich specimens for interfacial toughness testing. Interfacial fracture toughness (strain energy release rate, G) was measured as a function of mode mixity by changing loading angles from 0 degrees to 15 degrees. The interfacial fracture surfaces were then examined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) to determine the failure modes when loading angles changed. A computational model was also developed to calculate the driving forces, stress intensity factors and mode mixities. Interfacial toughness increased from approximate to 1.5 to 3.2 J/m(2) when the loading angle increases from approximate to 0, 0 to 15 degrees. The hybridized dentin/cement interface appeared to be tougher than the resin cement/quartz-fiber reinforced epoxy. The Brazil-nut sandwich specimen was a suitable method to investigate the mechanical integrity of dentin/cement/FRC interfaces. (C) 2011 Elsevier B.V. All rights reserved.

Influência de sistemas adesivos e da região do dente na durabilidade da união entre dentina e pino de fibra

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mites (Mesostigmata, Prostigmata, Astigmatina) associated with weeds among physic nut crops (Jatropha curcas L.: Euphorbiaceae) in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biological control of phytophagous arthropods in the physic nut tree Jatropha curcas L. in Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mites (Acari) associated with three species of the genus jatropha (euphorbiaceae) in Brazil, with emphasis on jatropha curcas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mites (Arthropoda: Acari) associated with three species of the genus Jatropha (Euphorbiaceae) in Brazil, with emphasis on Jatropha curcas L.

The physic nut (Jatropha curcas L.) (Euphorbiaceae) has emerged as a new option in cultivation aimed at biodiesel production. In order to provide information that may be useful to further develop management plans for that specific crop, samples of mites were collected from cultured and wild J. curcas plants in various regions of the country and from two other species of the same genus, Jatropha gossypiifolia L. and Jatropha mollissima (Pohl) Baill. in the northeastern region of Brazil. Altogether 31 species belonging to 10 families were recorded. The family Phytoseiidae presented the largest number of species (17). Polyphagotarsonemus latus Banks (Tarsonemidae) was the most abundant species (8,503 specimens). A dichotomous key was prepared to identify all the sampled species. At least four mite species of the samples deserve attention as showing potential for being pests in the crops of J. curcas, Brevipalpus phoenicis, Brevipalpus obovatus, Polyphagotarsonemus latus and Tetranychus bastosi, the latter two often found in great abundance.