Papers by Keyword: Glass Ionomer Cement

Abstract: The purpose of this study was to evaluate the effect of adding horn beetle nano chitosan (NCH) to Glass Ionomer Cement (GIC) liquid on surface roughness. The evaluation was done before and after the addition of NCH and from the length of time soaking in artificial saliva. The disc sample with a diameter of 6 mm and a height of 3 mm of total 40 samples were divided into four groups: the GIC control group, GIC modified NCH 0.5%, 1%, and 2%. Each sample was immersed for 24 hours and seven days in artificial saliva. Surface roughness before and after immersion was measured using the Surtronic S-100 Series Surface Roughness Tester. Data analysis was performed using a one-way ANOVA test to determine the effect of adding horn beetle NCH and paired t-test to determine the effect of immersion time on the surface roughness of GIC. Although the highest surface roughness values were found in sample GIC modified NCH 1% (2.51±0.86 for 24 hours) and in sample GIC modified NCH 2% (2.64±0.84 for 7 days), there was no significant differences for both the surface roughness with the addition of NCH (p > 0.05) and the length of immersed time (p > 0.05). As the conclusion, there is no effect of horn beetle nano chitosan to GIC surface roughness. However, the addition of horn beetle NCH presented rougher surfaces after immersion. These experiments can help predict the performance of these materials under clinical conditions.

Abstract: Controlled ion release property of nanoporous silica particles (NPS) were investigated using cationic fluorescent dye, rhodamine B. The dye was charged into a glass ionomer cements (GIC) pellet containing the particles and then the pellet were immersed into distilled water. The dye-release behavior was observed using a UV-vis. spectrophotometer. GIC containing NPS can release the dye for a couple of weeks, where as other samples released it only a few days. This result suggests that NPS has excellent sustained dye-release property.

Abstract: The aim of the study was to evaluate the surface hardness of two different traditional glass ionomer cements after their exposure to two commercial oral rinsing solutions. Fuji IX GP (GC Corporation, Tokyo, Japan) and Ketac Molar Easymix (3MESPE, Germany) were used in the study. Twenty-one cement samples of each material were split in three groups. In control group the samples were stored in artificial saliva (AFNOR NF S90-701) for 14 days. In groups 2 and 3 the samples of each material were immersed in Listerine and in Corsodyl two times on a day for 14 days. Between the immersion periods the samples were stored in artificial saliva. The samples were subjected to microhardness evaluation using digital microhardness tester (Micro-Vickers Hardness System CV-400DM^TM, CV Instruments Namicon). Significant results were obtained when compared the surface hardness of both glass ionomer cements after their immersion in Listerine and in Corsodyl to control group. The surface hardness of Fuji IX in control and in study groups was significantly higher when compared to Ketac Molar Easymix In the conditions of the study, Listerine and Corsodyl decreased the surface hardness of Fuji IX GP and Ketac Molar Easymix glass ionomer cements.

Abstract: Aiming at inadequate mechanical properties of Glass ionomer cement (GIC) commonly used in dental clinic, commercial and melt quenched GIC powders as control groups, homemade GIC powder was prepared by sol–gel route and modified by Nb₂O₅. The GIC samples were characterized by X-ray Diffraction (XRD), particle size analysis, Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FT-IR). The compressive strength, Vickers hardness, working and net setting time were tested. The data was analyzed by one-way ANOVA. The XRD results showed that commercial, melt quenched and sol gel GIC powders were similar amorphous. D90 of three GIC powders and Nb₂O₅ powder were 26 μm, 17 μm, 29 μm and 19 μm respectively. 5% Nb₂O₅-GIC exhibited the highest values of compressive strength and Vickers hardness, which were 112.93 Mpa, 139.48 MPa and 142.25 MPa respectively, increased 19.11%, 30.56% and 16.51% (P <0.05); the Vickers hardness were 35.15 MPa, 36.23 MPa and 37.62 MPa, increased 18.03%, 29.95% and 16.32% (P <0.05) compared to those of unmodified GICs as well. There was no significant change of the FT-IR characteristic peaks of modified GIC. The working time of three kinds of GIC were 4'58 ", 3'28" and 4'10 ", the net setting time were 5'16", 3'15 "and 4'38" (standard is 1.5-6 minutes). It was concluded that the dispersion stiffened effect of niobium oxide could improve the mechanical properties of the filling GIC without affecting the clinical operating performance.

Abstract: Experimental glass ionomer cement was prepared for the purpose of this study. Twenty disk specimens (16mm diameter x 10mm height) of test-GIC were prepared for the diametral tensile strength (DTS) test and twenty cylindrical specimens (6 mm diameter x 16mm height) were prepared for the compressive strength (CS) test. Specimens were stored in an artificial saliva at 37º C and (50±10%) of relative humidity in an incubator until testing. Five specimens of each GIC were submitted to CS and DTS test in each period, namely 1 hour, 24 hours, 7 days and 28 days. The specimens were tested in a Universal Testing Machine (Instron 1122, Instron corp., High Wycombe, U.K.) at a crosshead speed of 1.0mm/min for CS and 0.5mm/min for the DTS test until failure occurred. The results have revealed that incorporation of lithium fluoride in the formula of the test GIC might impart an increase in the mechanical properties of the GICs

Abstract: This study aimed to evaluate the anticariogenic and remineralization effects of the glass ionomer dental luting cement containing nano-β-TCP in vitro. The β-Tricalcium Phosphate (β-TCP) are the components of dental enamel and bone mineral as biological apatites. In addition, β-TCP contains a significant amount of calcium and phosphate, which can promote remineralization of enamel subsurface lesions in animal and human. RelyXTM glass ionomer cement(3M/ESPE, USA) was used as dental luting cement. Film thickness, setting time, and compressive strength was measured for each group of pure glass GIC, 15% nano-β-TCP GIC. Human molars were prepared in box-shaped cavities that were filled with the GIC with and without the 15% nano-β-TCP were placed in 25ml of pH 5.0 acid buffer for 4 days at 37°C. After 4 days, longitudinal sections (1007m) were obtained through the center of each restoration. The sections were analyzed using a scanning electronic microscope (SEM) and confocal laser scanning microscopy (CLSM) to identify the change in the enamel surface. A significant difference in the CLSM images between pure GIC and nano-β-TCP-GIC. CLSM allows the demineralized surface layers of sound enamel to be visualized down to approximately 100 μm. The pure GIC specimens had a relatively thick fluorescent layer. On the other hand, the fluorescent layer of the nano-β-TCP-GIC specimens were thinner. The SEM images of micro surfaces demonstrate that nano-β-TCP-GIC is less rough than pure GIC. Therefore, the addition of nano-β-TCP enhanced protection against acid demineralization and promoted remineralization of enamel surface.

Abstract: In this study, the antibacterial effects of glass ionomer cement containing silver-zeolite were evaluated. New antibacterial glass ionomer cements with silver-zeolite were prepared as follows. Silver-zeolite (1, 3, and 5 wt%) was incorporated into the glass ionomer cement powder and then mixed with the polyacidic liquid at the ratio recommended by the manufacturer. Agar diffusion test was used to evaluation of antibacterial effect. Setting time, film thickness and compressive strength were also determined. Paired samples t-tests and ANOVA were used, and P<0.05 was considered significant. Film thickness and setting time were increased dependent on the amount of silver-zeolite. Glass ionomer cement with 1 wt% of silver-zeolite seemed to increase the compressive strength. However, increasing ratio of compressive strength was diminished beyond 3 wt%. Glass ionomer cements containing silver-zeolite have been successfully demonstrated to have antimicrobial effects on S. mutants in vitro. These results indicate that glass ionomer cement containing silver-zeolite have the potential to enhance antibacterial of dental cement in oral cavity.

Abstract: Previous studies have shown that hydroxyapatite increases the bonding strength of dental luting cement with human teeth by forming bone-like apatite when it is added to cement. However, due to the low solubility of the hydroxyapatite, its ability to form bone-like apatite decreases in protein-free acellular simulated body fluid with ion concentrations nearly equal to those of the human blood plasma. The purpose of this experiment was to increase the formation of bone-like apatite by mixing hydroxyapatite with β-TCP of high solubility. RelyXTM glass ionomer cement(3M/ESPE, USA) was used as dental luting cement. Film thickness, setting time, and compressive strength was measured for each group of 15% hydroxyapatite, 15% β-TCP, and 15% mixed hydroxyapatite and β-TCP (85:15). Every specimen of each group was immersed in the simulated body fluid for four week before measuring bonding strength, and then their sectional surface was observed under SEM. The most noteworthy result was that the group containing β-TCP produced more amount of bone-like apatite compared with the group composed of only hydroxyapatite.

Abstract: The bioactivity of a glass ionomer luting cement (Ketac®-cem, ESPE, Germany), which was modified by Bioglass® (PerioGlas® Synthetic Bone Graft Particulate, US Biomaterials) in different bioglass/powder weight ratios, and the biocompatibility of the produced mixtures were evaluated in this study using different cell lines. The incorporation of Bioglass® in the cement structure resulted in the formation of sparsely located biological apatite aggregations. However, although Bioglass® incorporation seemed to enhance cell proliferation, the materials became eventually brittle and highly soluble depending on Bioglass® amount.

Abstract: Glass-ionomer cements (GIC) have been used in dentistry for over 30 years. In the past ten years they have also been developed for use as medical grade bone cements. However, concerns have been raised over the biocompatibility of GIC’s in non-dental applications. The release of Al3+ ions from the cement has been related to localized poor bone mineralisation and neurotoxicity. There is a need therefore to develop Al2O3-free cements. One potential route is the substitution of Al2O3 with Fe2O3 in the glass. An Fe2O3-based glass for use in GIC‘s was fabricated. The glass was found to differ considerably compared to the traditional amorphous Al2O3-based glasses. XRD demonstrated a highly crystalline morphology containing magnetite and apatite which was confirmed using electron microscopy. It was predicted that the reduction in Al concentration in the glass would improve the biocompatibility of the resulting cement.