Effect of Nanofeatured Topography on Ceria-Stabilized Zirconia/Alumina Nanocomposite on Osteogenesis and Osseointegration.

PURPOSE: The objective of this study was to evaluate the osteogenic and osseointegration capability of the Ce-tetragonal zirconia polycrystal (TZP)-based nanostructured zirconia/alumina composite (Ce-TZP/Al2O3) that was treated with hydrofluoric acid (HF). MATERIALS AND METHODS: Osteogenic MC3T3-E1 cells were cultured on acid-etched titanium (AETi) disks and Ce-TZP/Al2O3 disks without HF treatment (Zr[0%]), with 4% HF treatment (Zr[4%]), or with 55% HF treatment (Zr[55%]) for 24 hours, and biologic responses were compared among four conditions in vitro. Miniature implants of AETi and Zr(55%) were surgically placed in the femora of rats. Osseointegration was evaluated by a biomechanical push-in test after 2 and 4 weeks of healing. RESULTS: The surface of Zr(55%) rendered nanofeatured topography with a greater surface area and roughness, and extensive geographical undercut as ceria-zirconia crystal disappeared from the superficial layer and was similar to the surface morphology of biomineralized matrices. Culture studies showed that the attachment, proliferation, spread, and functional phenotypes of osteogenic cells, such as alkaline phosphatase activity and bone-related gene expression, were remarkably increased on the Zr(55%) surface. The strength of osseointegration measured using the biomechanical push-in test in a rat model was stronger for Zr(55%) implants than for AETi implants by 1.6 fold. CONCLUSION: The nanostructured Ce-TZP/ Al2O3 surface substantially enhanced the osteogenic response in vitro and the osseointegration capability in vivo, which suggest its potential clinical application as a novel implant material.

Comparison of the effects of surface treatments on roughness of two ceramic systems.

OBJECTIVE: The aim of this study was to evaluate the effects of different surface treatments on the surface roughness of lithium disilicate-based core (IPS Empress 2, shade 210, Ivoclar Vivadent, Schaan, Liechtenstein) and feldspathic ceramics (Vita VM9, VITA Zahnfabrik H. Rauter GmbH & Co. KG, Bad Säckingen, Germany). BACKGROUND DATA: Er:YAG laser irradiation is expected to be an alternative surface treatment, thus enhances surface roughness of procelains and produces morphological changes. METHODS: Fifty lithium disilicate-based core ceramic discs and 50 feldspathic ceramic discs were prepared (diameter, 10 mm; thickness, 1 mm) according to the manufacturers' instructions. All-ceramic discs were polished to standardize, and surface roughness of the discs was evaluated before treatment and serving as controls. Both of two ceramic groups were divided into five groups (n=10), and the following treatments were applied: (1) sandblasting with aluminum oxide (Al(2)O(3); Group SB); (2) Al(2)O(3)+Er:YAG laser (Group SB-L); (3) Er:YAG laser irradiation (distance, 1 mm; 500 mJ; 20 Hz; 10W; manually, contact handpiece [R 14]) (Group L); (4) 5% hydrofluoric acid etching (Group HF); and (5) Er:YAG laser +5% hydrofluoric acid (Group HF-L). Surface roughness was evaluated by profilometry, and specimens were then examined with atomic force microscopy. RESULTS: Data were analyzed by Wilcoxon signed rank, Mann-Whitney U, and Kruskal-Wallis tests (α=0.05). The Wilcoxon signed rank test results indicated that surface roughness after sandblasting was significantly different from the surface roughness after laser irradiation and acid etching (p<0.001). Mann-Whitney U and Kruskal-Wallis test results indicated that groups SB and SB-L had significantly higher mean roughness values (p<0.05) than those in the other groups. CONCLUSIONS: Groups SB and SB-L had rougher surfaces than the groups subjected to the other surface treatment methods. There was no significant difference in surface roughness between the HF acid etching, Er:YAG laser irradiation, and HF and Er:YAG (p<0 .05).

Influência do tratamento superficial na resistência à traçäo da colagem do Artglass / Influence of superficial treatment on the Art Glass shear bond strength

O objetivo deste foi avaliar a influência do jateamento com óxido de alumínio, do condicionamento com ácido fluorídrico e ácido fosfórico no tratamento superficial do polímero de vidro Artglass (HERAEUS, Kulzer - Germany), verificando o efeito da aplicaçäo de agentes ativadores de superfície na resistência a traçäo. Os autores concluíram que o maior valor de resistência de uniäo é obtido com jateamento com óxido de alumínio associado ao silano; a análise por M.E.V. da morfologia superficial demonstrou um padräo favorável ao embricamento micromecânico quando do jateamento com óxido de alumínio

[ Dynamics of NAD-dependent isocitrate dehydrogenase activity in homogenized rat liver exposed to toxic products of the phosphorus industry]. / Dinamika akivnosti NAD-zavisimoi izotsitratdegidrogenazy v gomogenatakh pecheni krys pod deistviem vrednykh veshchestv fosfornogo proizvodstva.

Dynamic studies showed that the combined action of phosphine and hydrofluoric acid damages the Krebs cycle reactions, dehydrogenization of isocitrate and synthesis of citrate in homogenized rat liver. Yellow phosphorus harmed the citrate synthetic reaction of citric acid cycle in homogenized rat liver as well. That activated the alternative action principles in the cycle. The main cause of such disorders in the Krebs cycle in likely to be the abnormal fat metabolism induced by toxic products of phosphorus industry.

Role of wall phosphomannan in flocculation of Saccharomyces cerevisiae.

Treatment with 60% hydrofluoric acid (HF) removed most of the phosphorus and small amounts of mannan, glucan and protein from walls of two non-flocculent strains (NCYC366 and NCYC1004) and two flocculent strains (NCYC1005 and NCYC1063) of Saccharomyces cerevisiae. Organisms of all strains showed increased flocculating ability following HF treatment. Flocculation of untreated organisms of NCYC1005 and NCYC1063, and of HF-treated organisms of all four strains, declined appreciably when they were washed in deionized water, with or without EDTA, and the flocculation was measured in deionized water instead of in 0-05 M-sodium acetate containing Ca2+. Treatment with 1,2-epoxypropane also caused a decrease in the flocculating ability of these organisms. Extracting the lipids from organisms of strains NCYC366 and NCYC1004 had no effect on their flocculating ability, but decreased the flocculating ability of organisms of strains NCYC1005 and NCYC1063. pH-electrophoretic mobility curves of untreated and HF-treated organisms confirmed the loss of wall phosphate by HF treatment, and indicated that HF treatment had little effect on the content of protein carboxyl groups in the outer wall layers. Mannose at 0-22 M completely prevented floc formation by organisms of strain NCYC1063; but, even at 0-33 M, it had very little effect on floc formation by HF-treated organisms of strains NCYC366 and NCYC1063. Organisms of all four strains bound fluorescein-conjugated concanavalin A to the same extent after treatment with HF as before, but this treatment led to a greatly diminished binding of of fluorescein-conjugated antiserum raised against organisms of strain NCYC366. The results indicate that phosphodiester linkages in yeast-wall mannan are not involved in bride formation through Ca2+ during floc formation and that this arises principally through carboxyl groups.