3 research outputs found

    Effect of new zirconia surface coatings on the surface properties and bonding strength of veneering zirconia substrate

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    Zirconia ceramic dental restorations showed a low bond strength to veneering ceramic because of there is no inherent glass content along with a nonpolar covalent bond in its matrix. Two zirconia coatings by airbrush spraying were used as a new surface treatment on zirconia substrate to create surface roughness and improved bond strength to the veneering ceramic. Unsintered yttria stabilized zirconia (YSZ) powder was partially sintered at 1100 °C to produce powders with two particle sizes; A = 26.0 ± 0.3 μm and B = 47.0 ± 0.5 μm. Unsintered YSZ blocks were sectioned into 50 discs of 25 mm in diameter and 2.5 mm in thickness. The discs were divided according to the surface treatments into three groups; ten sintered YSZ discs were blasted by airborne particle abrasion (APA) with 50 μm aluminium oxide particles as control group; twenty unsintered YSZ discs were coated with a mixture of glaze ceramic and YSZ powders (M1), and twenty unsintered YSZ discs were coated with a mixture of ceramic liner and YSZ powders (M2). Based on the sizes of the YSZ powders, the coated groups subdivided into M1A, M1B, M2A and M2B. The surface area roughness (Sa), surface morphology, elemental composition, phase transition and shear bond strength test (SBS) were assessed. The collected data were analysed with one-way ANOVA and Tukey HSD test at (P < 0.05). The Sa results revealed significant differences among all groups (P < 0.000). The coated groups showed higher Sa and SBS values with a significant difference than APA. The M1B group exhibited higher values of Sa (10.33 μm) and SBS (37.54 MPa) with significant differences among the other tested groups. The zirconia specimens treated with new coatings significantly improved the shear bond strength to the veneering ceramic

    An injectable poly(caprolactone trifumarate-gelatin microparticles) (PCLTF-GMPs) scaffold for irregular bone defects: Physical and mechanical characteristics

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    Recently, a modified form of a three-dimension (3D) porous poly(caprolactone-trifumarate) (PCLTF) scaffold has been produced using a fabrication technique that involves gelatin microparticles porogen leaching. This poly(caprolactone trifumarate-gelatin microparticles) (PCLTF-GMPs) scaffold has been shown to be biocompatible, more flowable clinically, and has a shorter degradation time as compared to its existing predecessors. In this report, a detailed characterization of this new scaffold was performed by testing its cytocompatibility, analyzing the surface topography, and understanding its thermal, physical and mechanical properties. The result showed that the PCLTF-GMPs has no critical cytotoxic effect. To confirm improvement, the surface properties were compared against the older version of PCLTF fabricated using salt porogen leaching. This PCLTF-GMPs scaffold showed no significant difference (unpaired t-test; p > 0.05) in mechanical properties before and after gelatin leaching. However, it is mechanically weaker when compared to its predecessors. It has a high biodegradability rate of 16 weeks. The pore size produced ranges from 40 to 300 mu m, and the RMS roughness is 613.7 +/- 236.9 nm. These characteristics are condusive for osteoblast in-growth, as observed by the extension of filopodia across the macropores. Overall, this newly produced material has good thermal, physical and mechanical properties that complements its biocompatibility and ease of use. (C) 2016 Elsevier B.V. All rights reserved

    Using calcium sulfate cement-Hydroxypropyl methyl cellulose/sodium alginate composites as substitutes of bone wax

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    Development of alternatives of bone wax to stop blood transfusion occurred in cancellous bone injury is highly deserved clinically. An ideal candidate is supposed to be not only biodegradable, biocompatible, malleable, and cost-effective, but also have comparable mechanical strength to cancellous bone. In the present work, calcium sulfate cement (CSC) based composites modified with hydroxypropyl methyl cellulose (HPMC) or sodium alginate (SA) were prepared. In brief, CSC was combined with 2, 4, 6 wt.% of HPMC or SA, respectively, followed by setting behavior evaluation, compressive strength and degradation testing, XRD, and SEM characterizations, as well as blood clotting induction study. Both additives improved the hemostatic performance of CSC, but CSC with 2% wt. SA exhibited the optimum setting time, mechanical strength, stability, and blood clotting ability. These results reveal the feasibility of using CSC–SA based composite as a substitute for bone wax