Search results for "Adhesive"
showing 10 items of 299 documents
Bonding efficacy of an acetone/based etch-and-rinse adhesive after dentin deproteinization
2012
Objectives: to evaluate the effect of sodium hypochlorite (NaOCl) treatment on dentin bonding by means of shear bond strength (SBS) measurements when using Prime&Bond NT (PB NT) adhesive. Ultrastructure of the interfaces was examined by scanning electron microscopy (SEM). Study design: Extracted human third molars were sectioned and ground to expose flat surfaces of superficial or deep dentin. Specimens were randomly assigned to two equal groups, and bonded as follows: (1) according to the manufacturers’ directions, after 35% H3PO4 etching, (2) 5% NaOCl treated for 2 minutes, after 35% H3PO4 etching. Each sample was embedded in a Watanabe shear test assembly for a single plane lap shear. Af…
Effect of postbleaching application of an antioxidant on enamel bond strength of three different adhesives
2010
Objectives: The aim of this study was to compare the shear bond strength (sbs) of three different adhesives on bleached enamel immmmediately after bleaching, bleached/delayed for 1 week, and bleached/applied antioxidizing agent. Study Design: The enamel surfaces of 144 freshly extracted incisors without any caries and restorations were flattened and divided into 12 groups. The following adhesives were investigated: Optibond FL (OFL) (three-step etch&rinse), Optibond Solo Plus (OSP) (two-step etch&rinse), Optibond All-in-One (OA) (one-step self-etch), (Kerr, Orange, USASA). Unbleached enamel groups were prepared as negative controls. The remainder surfaces were bleached with 20% Opalescent P…
Interfacial fracture toughness of universal adhesive systems treated with an antioxidant
2017
Background Secondary caries, degradation of the dentin-resin interface and fracture of the restoration are the most common forms of failure. The aim of this study was to assess the interfacial fracture toughness of three different adhesive approaches and to compare their fracture toughness after surface treatment with antioxidant. Material and methods Seventy two dentin blocks with 3×4mm dimension and 3mm thickness were prepared and attached to precured 3×4×12mm composite blocks from both sides. Six adhesive groups (N=12), All-bond universal, Scotchbond universal and Clearfil SE bond with or without antioxidant treatment (Sodium Ascorbate 10% )were applied to dentin surfaces, a 160µ polyeth…
Effect of sodium ascorbate on the bond strength of all-in-one adhesive systems to NaOCl-treated dentin
2015
Background: Ascorbic acid and its salts are low-toxicity products, which are routinely used in food industries as antioxidants. The aim of the present study was to evaluate the effect of 10% sodium ascorbate on the bond strength of two all-in-one adhesive systems to NaOCl-treated dentin. Material and Methods: After exposing the dentin on the facial surface of 90 sound human premolars and mounting in an acrylic resin mold, the exposed dentin surfaces were polished with 600-grit SiC paper under running water. Then the samples were randomly divided into 6 groups of 15. Groups 1 and 4 were the controls, in which no surface preparation was carried out. In groups 2 and 5 the dentin surfaces were …
Direct infusion mass spectrometry as a fingerprint of protein-binding media used in works of art
2005
A direct infusion mass spectrometry method for the characterization of proteinaceous glues from binding media used in pictorial works of art prior to conservation or restoration treatment is proposed. Amino acids are released by acid hydrolysis and dissolved in a mixture of acidic water and ethanol. This mixture is directly infused into a mass spectrometer without any derivatization. The mass spectrometer is operated in positive ion electrospray mode (ESI-MS) to yield [M+H]+ ions for the amino acids. Relative amounts of each amino acid are calculated for each protein (beef and porcine gelatines, albumin, casein and egg). The analyzed proteins were satisfactorily distinguished. The method is…
Crack growth analysis at adhesive–adherent interface in bonded joints under mixed mode I/II
2008
The propagation of an interface crack subjected to mixed mode I/II was investigated for two 2024-T351 aluminum thin layers joined by means of DP760 epoxy adhesive produced by 3M©. On the basis of beam theory, an analytical expression for computing the energy release rate is presented for the mixed-mode end loaded split (MMELS) test. The analytical strain energy release rate was compared by finite element (FE) analysis using the virtual crack closure technique (VCCT). Several fatigue crack growth tests were carried out in a plane bending machine to compare the experimental energy release rates to those of the analytical and FE solutions. Experimental results showed the relationship between t…
New model describing the total dispersion of dry powder agglomerates
2010
Micron and submicron particles tend to form agglomerates due to adhesive and cohesive forces. The disintegration of these dry powder agglomerates often represents a major task in powder technology. One model describing the mechanical stability of granulates is given by the planar fracture model of Rumpf. In the present work, a new model is introduced intended for applications where a complete disintegration of dry powder agglomerates is required (e.g. for pharmaceutical aerosol generation). Therefore, the breakup of every single connection inside an agglomerate is considered and the dispersion strength σdisp of model agglomerates is calculated and discussed. In order to balance the stabilit…
Effect of proanthocyanidin mediated immediate and delayed dentin sealing on the strength of premolars restored with composite resin inlay.
2019
Background Immediate dentin sealing (IDS) with proanthocyanidin (PA) could be used before cementation with a self-adhesive (SA) cement. The aim of this study was to assess the effect of PA treatment on acid-etched dentin before adhesive application, in IDS and delayed dentin sealing (DDS), on the strengthening property of SA-cemented composite resin inlay in premolars. Material and Methods Eighty-four maxillary premolars were divided into 7 groups (n=12): 1) (Intact) Sound teeth served as controls; groups 2-7) After cavity preparation and fabrication of composite resin inlay, temporary inlays were made and cemented. After one week, the inlays were removed and composite inlays were luted wit…
Mechanical desorption of a single chain: unusual aspects of phase coexistence at a first-order transition.
2012
The phase transition occurring when a single polymer chain adsorbed at a planar solid surface is mechanically desorbed is analyzed in two statistical ensembles. In the force ensemble, a constant force applied to the nongrafted end of the chain (that is grafted at its other end) is used as a given external control variable. In the $z$-ensemble, the displacement $z$ of this nongrafted end from the surface is taken as the externally controlled variable. Basic thermodynamic parameters, such as the adsorption energy, exhibit a very different behavior as a function of these control parameters. In the thermodynamic limit of infinite chain length the desorption transition with the force as a contro…
Understanding the physicochemical properties of olive kernel to be used as a potential tool in the development of phenol-formaldehyde wood adhesive
2015
Abstract During olive oil production process, a great number of by-products are generated, including olive kernel. These by-products can be used for the development of new products for use in many different industrial applications. The evaluation of the physicochemical properties of these by-products constitutes a key factor in evaluating the potential reutilization of olive oil by-products. In the present study, the physicochemical properties of olive kernel were analyzed. Fourier transform infrared spectroscopy (FT-IR), cross-polarization magic angle spinning 13 C nuclear magnetic resonance (CP/MAS 13 C NMR), Brunauer, Emmett and Teller (BET), scanning electron microscopy (SEM) and thermo…