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Bonding Characteristics (bonding + characteristic)
Selected AbstractsBonding characteristics of newly developed all-in-one adhesivesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2007S. K. Sidhu Abstract This study evaluated the microtensile bond strength and the interfacial morphology of newer adhesives. The occlusal surfaces of extracted teeth were ground flat for random allocation to four equal groups. Resin composite was bonded to each surface using either Clearfil SE Bond [SEB], Clearfil Protect Bond [PB], G-Bond [GB], or an experimental adhesive, SSB-200 [SSB]. After storage for 24 h in water at 37°C, they were sectioned into beams (cross-sectional area 1 mm2) for microtensile bond strength testing (,TBS) at a crosshead speed of 1 mm/min. The load at failure of each was recorded; the data were analyzed by one-way ANOVA and Games Howell tests. The surfaces of the fractured specimens were observed using SEM. For the ultra-morphology of the interface, the occlusal surfaces of four more teeth were prepared as before and a thin layer of flowable resin composite was bonded to each surface using one of the four adhesives. The mean ,TBS ranged from 39.68 MPa (GB) to 64.97 MPa (SEB). There were no statistical differences between SEB and SSB, or between PB and GB (p > 0.05). The ,TBS of SEB and SSB were significantly greater than that of PB and GB (p < 0.05). SEMs of the fractured surfaces revealed a mixed (cohesive/interfacial) failure. TEM examination highlighted differences in the hybrid layer; SEB had a thicker layer than the others. In conclusion, the newer all-in-one adhesives produced a thin hybrid layer but varied in their bond strengths. The 2-step self-etching adhesives do not necessarily produce higher bond strengths than that of the all-in-one systems. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source] Antimicrobial Gallium-Doped Phosphate-Based Glasses,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2008Sabeel P. Valappil Abstract Novel quaternary gallium-doped phosphate-based glasses (1, 3, and 5 mol % Ga2O3) were synthesized using a conventional melt quenching technique. The bactericidal activities of the glasses were tested against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Clostridium difficile) bacteria. Results of the solubility and ion release studies showed that these glass systems are unique for controlled delivery of Ga3+. 71Ga NMR measurements showed that the gallium is mostly octahedrally coordinated by oxygen atoms, whilst FTIR spectroscopy provided evidence for the presence of a small proportion of tetrahedral gallium in the samples with the highest gallium content. FTIR and Raman spectra also afford an insight into the correlation between the structure and the observed dissolution behavior via an understanding of the atomic-scale network bonding characteristics. The results confirmed that the net bactericidal effect was due to Ga3+, and a concentration as low as 1 mol % Ga2O3 was sufficient to mount a potent antibacterial effect. The dearth of new antibiotics in development makes Ga3+ a potentially promising new therapeutic agent for pathogenic bacteria including MRSA and C. difficile. [source] Competitive coordination between lead and oligoelements with respect to some therapeutic heavy-metal chelatorsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 11 2008C. Gourlaouen Abstract The competitive complexation of Ca2+, Fe2+, Cu2+, Zn2+, and Pb2+ toward ethylene diamine tetraacetate (EDTA), dimercaprol and D -penicillamine, three liganding agents commonly used in chelation therapy against heavy metal, especially lead, poisonings is examined by means of B3LYP calculations, natural population analyses, and the topological analysis of the electron localization function. It is shown that Pb2+ can displace any of Ca2+, Fe2+, Cu2+, or Zn2+ chelated by any of dimercaprol or D -penicillamine, but can only displace Ca2+ if EDTA is concerned. The first two chelators thus appear as better entities than EDTA to be used in chelation therapy, where in vivo selective complexation is essential. Moreover, the comparison of the bonding characteristics of Pb2+ with those of the other cations allows deriving three features to be taken into account in designing new chelators expecting to have an increased selectivity toward this cation. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Adhesive bonding of super-elastic titanium,nickel alloy castings with a phosphate metal conditioner and an acrylic adhesiveJOURNAL OF ORAL REHABILITATION, Issue 6 2003H. Matsumura summary, The purpose of the current study was to evaluate the bonding characteristics of super-elastic titanium,nickel (Ti,Ni) alloy castings. Disk specimens were cast from a Ti,Ni alloy (Ti-50·85Ni mol%) using an arc centrifugal casting machine. High-purity titanium and nickel specimens were also prepared as experimental references. The specimens were air-abraded with alumina, and bonded with an adhesive resin (Super-Bond C & B). A metal conditioner containing a phosphate monomer (Cesead II Opaque Primer) was also used for priming the specimens. Post-thermocycling average bond strengths (MPa) of the primed groups were 41·5 for Ti,Ni, 30·4 for Ti and 19·5 for Ni, whereas those of the unprimed groups were 21·6 for Ti, 19·3 for Ti,Ni and 9·3 for Ni. Application of the phosphate conditioner elevated the bond strengths of all alloy/metals (P < 0·05). X-ray fluorescence analysis revealed that nickel was attached to the debonded resin surface of the resin-to-nickel bonded specimen, indicating that corrosion of high-purity nickel occurred at the resin,nickel interface. Durable bonding to super-elastic Ti,Ni alloy castings can be achieved with a combination of a phosphate metal conditioner and a tri- n -butylborane-initiated adhesive resin. [source] The effect of nitrogen incorporation on surface properties of silicon oxynitride filmsPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 1 2009Jongin Hong Abstract In order to investigate the surface heterogeneity of silicon oxynitride films, we observed the nanoscale variation of the surface potential by Kelvin probe force microscopy (KFM), the molecular bonding characteristics by Fourier transform infrared spectrometry (FTIR), and the wetting behavior by contact angle measurement. Nitrogen incorporation into silicon oxynitride films influenced the decrease in the surface potential and the polar component of the surface free energy. We present the first correlation between the nanoscale measurement of the surface potential and the macroscopic measurement of the surface free energy in silicon oxynitride films grown by a standard plasma-enhanced chemical vapor deposition (PECVD) technique. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||