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Objectives: Evaluate color and translucency of both non-colored and colored zirconia ceramics and compare them with corresponding properties of human dentine., Methods: 0.5mm thick samples of human (MSHD) and bovine (MSBD) dentine were obtained from 5 extracted human anterior maxillary teeth and 5 bovine incisors, respectively. The zirconia systems evaluated (0.5mm samples) were: (1) IPS e.max(®) ZirCAD sintered samples: (a) regular (ZC1); (b) colored - coloring liquid CL2 (ZC2); (2) LAVA™ Zirconia sintered samples: (a) regular (LV1); (b) colored - coloring liquid FS3 (LV2). Translucency parameter (TP) and ΔE(ab)(*) and ΔE(00) color differences (with respect to the MSHD) were calculated. Spectral reflectance curves were compared using the VAF coefficient., Results: Reflectance spectral behaviour of MSBD and MSHD were similar (VAF=99.3%). All zirconia samples showed higher spectral reflectance values than the MSHD. Lightness values obtained for all zirconia ceramics (especially LV) were higher than MSHD and MSBD. The range of color differences, with respect to MSHD, was 6.9-20.5 for ΔE(ab)(*) and 4.9-15.6 for ΔE(00). Colored samples showed lower color differences with respect to MSHD. The highest TP values were found for IPS e.max(®) ZirCAD system and the lowest for LAVA™ Zirconia system. In terms of translucency, MSHD, MSBD and zirconia ceramics showed no statistically significant differences., Conclusions: In terms of translucency, the studied zirconia systems could satisfactorily replace the human dentine within a dental restoration but, in order to produce a clinically acceptable match, it is necessary to carefully adjust the color of these systems., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objective: To evaluate whether bilayer chitosan scaffolding (BChS) can provide a watertight dural closure and permit regeneration by fibroblasts in an experimental in vivo model., Methods: In the in vitro phase, BChS was elaborated and the following characteristics were evaluated: pore size, thickness, water absorption capacity, tensile strength, strain, and toughness. In the second in vivo phase, 27 durectomized New Zealand rabbits were randomly assigned into three duraplasty groups with autologous dura, collagen matrix (CM), or BChS. In all groups, fluid leakage pressure was measured at 10, 21, or 180 days. Histology response to regeneration was evaluated through hematoxylin and eosin stain., Results: BChS was standardized to obtain bilayer scaffoldings with a nonporous layer and a porous layer. The pore size was 10 μm, total thickness was 400 μm, strain was 57.8%, and tensile strength was 5.5 gr/mm(2). The physical characteristics of BChS allowed dural closure without cerebrospinal fluid (CSF) leak. There were no differences in fluid leakage pressures between the BChS, dura, and CM groups. Histologic analysis showed fibroblast migration with adequate dural regeneration., Conclusions: BChS is an ideal alternative for a watertight dural closure because it can be sutured, and it induces organized regeneration with fibroblasts without evidence of fibrosis., (Copyright © 2012 Elsevier Inc. All rights reserved.)