Authors: Minna Vaahtio, Eveliina Munukka, Outi Leppäranta, Di Zhang, Erkki Eerola, Heimo O. Ylänen, Timo Peltola
Abstract: Four different bioreactive ceramics were prepared using a sol-gel method and a standard melting process. The aim was to study antibacterial effect of these materials on the growth of Staphylococcus epidermidis. The dissolution (Si and Ca ions) of fine (≤ 45 !m) ceramic powders in a tryptone soya broth (TSB) was investigated. Also the pH changes in TSB solution were measured.
In addition the adherence of Enterococcus faecalis (Ef) to materials was investigated. The bacterial adhesion was studied using scanning electron microscopy (SEM). In the bacterial and the adhesion
test, CaPSiO2 and S53P4 had the strongest antimicrobial effect against studied bacteria. It was shown that bioreactive sol-gel derived ceramic with sufficient high Ca ion release (> 270 ppm) can reach strong antibacterial effect also at lower pH values (< 9.6).
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Authors: Shu Xia Ren, Hui Fang Yang, Xiu Shu Tian, Yan Fang Li
Abstract: The composite antibacterial agents were prepared with Medical stone containing Cu2+ and Zn2+ by liquid ion-exchange reaction. The ion exchange capacity of the as-prepared Medical stone composite antibacterial agents (MSAA) products were investigated by ICP-AES, and the antibacterial activities of the agents were tested by Bacteriastasis ratio, and the structures were characterized by XRD and SEM. The results show that the conditions of preparation, such as pH, concentrations of copper and zinc ions, reaction time and reaction temperature, have important influences on the ion exchange of MSAA. The maximum ion exchange capacity have been obtained when 0.2mol/l Cu2+ and 0.6 mol /l Zn2+ reacted with Medical stone powers in the solution with pH values of 8 for 8 hours at 50 °C. Meanwhile good antibacterial activities and safety are also gained. The reasons for causing the above results are that copper and zinc ions can enter the framework of Medical stone through ion exchanging and adsorption, and are released slowly owing to its porosity.
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Authors: Joanna Karaś, Andrzej Roman Olszyna, Ewa Zaczyńska, Anna Czarny, Krzysztof Szamałek
Abstract: The purpose of the study was to identify the influence of the amount of fluoride release from glass ionomer cements on survival of bacterial strains responsible for the development of secondary caries. All developed cements had an antibacterial impact on the strains used in the study. The study demonstrated that the cements exhibit greater antibacterial activity against Streptococcus mutans than Streptococcus sanguinis. The numbers of bacteria count in cultures on the developed cements were approximately 10 times lower compared to the control culture after 24 h, 48 h, 72 h and 7 days. The developed cements had initially (1-2 days) greater antibacterial impact against the strains used in the study, which corresponds to the greatest daily amount of fluoride released from the cements. Following the initial period, the antibacterial activity of all the cements remained roughly at the same level.
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Authors: Jing Yang, Xiao Wen Xu
Abstract: A composite, TiO2/AgY, was prepared by impregnation of tetrabutyl titanate solution on NaY zeolite, subsequent calcination at 500°C and ion-exchange with AgNO3 solution. XRD.SEM, TEM and EDAX were used to characterize the crystalline phase, the particle size of the formed nano-materials and the relative contents of atoms in TiO2/AgY and NaY zeolite, respectively. TiO2 nanoparticles with the size of 5-8 nm were found to form on the external surface of the zeolite. About half of Na+ in NaY zeolite is exchanged into Ag+. The as-prepared material exhibits excellent antibacterial activity and decompose E. coli using ultraviolet radiation as light resource.
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Authors: Atikom Surintanasarn, Krisana Siralertmukul, Niyom Thamrongananskul
Abstract: The aim of this study was to examine the effects of active filler in resin-based pit and fissure sealant on fluoride release and recharge abilities. Mesoporous silica was synthesized from tetraethyl orthosilicate (TEOS) using sol-gel method. Resin-based sealant was incorporated with 5% w/w of filler (<45 μm): synthesized mesoporous silica (S), calcium carbonate (C), and fluoro-alumino silicate glass (F). Resin-based sealant without filler added was the control. Ten specimens of each group were separately stored in 3 mL of deionized water and the fluoride concentration, before and after fluoride recharge, were measured every 3 days (from day 3 to day 27). Fluoride release before recharge was only found in F (0.1024±0.0077 ppm) and then gradually decreased to baseline. After two recharges, the highest fluoride release was found in S (0.0804±0.0095 ppm after first recharge and 0.0601±0.0092 after second recharge), followed by F (0.0386±0.0024 ppm after first recharge and 0.0313±0.0027 ppm after second recharge), and then decreased to baseline. Fluoride recharge was not found in C and control. This result suggested that resin-based pit and fissure sealant containing synthesized mesoporous silica filler has fluoride recharge ability which might prevent secondary caries at material-enamel interface.
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