Genotoxicity and cytotoxicity of glass ionomer cements on Chinese hamster ovary (CHO) cells

Glass ionomer cements are widely used in dentistry as restorative materials and adhesives for composite restorations. However, the results of genotoxicity studies using these materials are inconclusive in literature. The goal of this study was to examine the genotoxic and cytotoxic potential of three different glass ionomer cements available commercially (Ketac Cem, Ketac Molar and Vitrebond) by the single cell gel (comet) assay and trypan blue exclusion test, respectively. For this, such materials were exposed to Chinese hamster ovary (CHO) cells in vitro for 1 h at 37 degrees C. Data were assessed by Kruskall-Wallis nonparametric test. The results showed that the powder from Ketac Molar displayed genotoxicity only in the maximum concentration evaluated (100 mu g/mL). In the same way, the liquid from Vitrebond at 0.1% dilution caused an increase of DNA injury. Significant differences (P < 0.05) in cytotoxicity provoked by all powders tested of glass ionomer cements were observed for exposure at 1000 mu g/mL concentration. With respect to liquids of glass ionomer cements evaluated, the major toxic effect on cell viability was produced at 10%, beginning at the dilution of 0.5% for Vitrebond. Taken together, we conclude that some components of glass ionomer cements show both genotoxic and cytotoxic effects.

Biocompatibility of glass-ionomer cements using mouse lymphoma cells in vitro

Glass-ionomer cements are widely used in dentistry as restorative materials and adhesives for composite restorations. A number of genotoxicity studies have been conducted using these materials with results conflicting so far. Thus, the approach was aimed to look at the genotoxic and cytotoxic potential of three different glass-ionomer cements available commercially (Ketac Cem, Ketac Molar and Vitrebond) by the single cell gel (comet) assay and trypan blue exclusion test, respectively. For this, such materials were exposed to mouse lymphoma cells in vitro for 1 h at 37 degrees C. Data were assessed by Kruskall-Wallis non-parametric test. The results showed that all powders assayed did not show genotoxic effects. on the other hand, the liquid from Vitrebond at 0.1% dilution caused an increase of DNA injury. Significant statistically differences (P < 0.05) in cytotoxicity provoked by all powders tested were observed for exposure at 1000 mu g mL(-1) concentration and 100 mu g mL(-1) for Ketac Molar. With respect to liquids of glass-ionomer cements evaluated, the major toxic effect on cell viability was produced at 1%, beginning at the dilution of 0.5% for Vitrebond. Taken together, these results support the notion that some components of glass-ionomer cements show both genotoxic and cytotoxic effects in higher concentrations.

Retention of oral microorganisms on conventional and resin-modified glass-ionomer cements

A cárie secundária representa problema de saúde pública e socioeconômico no mundo. A restauração de dentes acometidos por cárie pode criar condições favoráveis à proliferação microbiana na superfície do material restaurador ou na interface dente/restauração, criando ambiente propício para o estabelecimento de cárie secundária. O objetivo deste estudo foi avaliar a capacidade de retenção de placa bacteriana em cimentos de ionômero de vidro convencionais (Chelon-Fil e Vidrion R) e modificados por resina (Vitremer e Fuji II LC) e de resina composta híbrida (Z100), utilizada como controle. Nos testes de retenção de microrganismos, in situ, 12 voluntários utilizaram, por 7 dias, placa de Hawley contendo corpos-de-prova de todos os materiais. A seguir, os corpos-de-prova foram transferidos para tubos contendo 2,0 ml de Ringer-PRAS e os microrganismos presentes em sua superfície foram cultivados em placa com ágar-sangue e ágar Mitis Salivarius Bacitracina, os quais foram incubados, a 37ºC, em anaerobiose (90% N2, 10% CO2), por 10 e 2 dias, respectivamente. Os ionômeros modificados por resina retiveram quantidade de bactérias similar àquela mostrada pela resina testada. Os ionômeros modificados por resina também apresentaram menor número de estreptococos do grupo mutans do que a resina e os cimentos ionoméricos convencionais. Os ionômeros de vidro convencionais apresentaram menor número de estreptococos do grupo mutans que a resina, sendo que essa diferença não foi estatisticamente significativa.

Short-term in situ/ex vivo study of the anticariogenic potential of a resin-modified glass-ionomer cement associated with adhesive systems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Short-term evaluation of the pulpo-dentin complex response to a resin-modified glass-ionomer cement and a bonding agent applied in deep cavities

Objectives. To evaluate the response of the pulpo-dentin complex following application of a resin-modified glass-ionomer cement or an adhesive system in deep cavities performed in human teeth.Methods. Deep class V cavities were prepared on the buccal surface of 26 premolars. In Group I the cavity walls (dentin) and enamel were conditioned with 32% phosphoric acid and the dentin adhesive system One Step (Bisco, Inc., Itasca, IL, USA) was applied. In Groups 2 and 3, before total etching and application of bonding agent, the cavity floor was lined with the resin-modified glass-ionomer cement-Vitrebond (3M ESPE Dental Products Division, St. Paul, MN, USA) or the calcium hydroxide cement-Dycal (control group, Dentsply, Mildford, DE, USA), respectively. The cavities were restored using light-cured Z-100 composite resin (3M ESPE). The teeth were extracted between 5 and 30 days and prepared for microscopic assessment. Serial sections were stained with H/E, Masson's trichrome, and Brown and Brenn techniques.Results. In Group 1, the inflammatory response was more evident than in Groups 2 and 3. Diffusion of dental material components across dentinal tubules was observed only in Group 1, in which the intensity of the pulp response increased as the remaining dentin thickness decreased. Bacteria were evidenced in the lateral walls of two samples (Group 2) which exhibited no inflammatory response or tissue disorganization.Conclusions. Based on the experimental conditions, it was concluded total acid etching followed by application of One Step bonding agent cannot be recommended as adequate procedures. In this clinical condition the cavity walls should be lined with a biocompatible dental material, such as Vitrebond or Dycal. 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

In vitro microhardness of glass ionomer cements

This study evaluated the surface microhardness of four glass ionomer cements and a composite resin (Fuji IX, Ketac Molar, Vidrion R, Vitromolar and Z 250). Ten specimens of each glass ionomer cement with 8.0 mm diameter and 5.0 mm high dimensions were made and Vicker's microhardness measurements were taken at 1 day and 1 week after initial setting reaction. The results were analyzed using Student's T test and Tukey test (p < 0.05) and demonstrated that the values of microhardness increased after 1 week, with the exception of Fuji IX. Resin composite Z250 presented the greatest values for microhardness.

Antibacterial activity of four glass ionomer cements used in atraumatic restorative treatment

The in vitro antibacterial activity of four glass ionomer cements ( Fuji IX, Ketac Molar, Vidrion R and Vitromolar) indicated for Atraumatic Restorative Treatment ( ART) was studied against strains of bacteria involved in the development of oral diseases, Streptococcus mutans, Streptococcus sobrinus, Lactobacillus acidophilus and Actinomyces viscosus. The agar plate diffusion test was used for the cultures, which included chlorhexidine as a positive control. The results demonstrated that all the cements evaluated presented antibacterial activity. Based on the results of this study, it can be concluded that Fuji IX and Ketac Molar presented the most effective antibacterial activity considering the ART approach.

In vitro cytotoxicity of five glass-ionomer cements

To evaluate the cytotoxic effects of five glass-ionomer cements (GICs) on an odontoblast cell line (MDPC-23), disks of every material were prepared and divided into Group 1: Vitrebond, Group 2: Vitremer, Group 3: Fuji IILC, Group 4: Fuji IX GP, Group 5: Ketac-Molar, Group 6: Z-100 (positive control). In Group 7, phosphate-buffered saline solution (negative control) was applied on filter paper. After placing the samples in the bottom of wells, the cells (30,000 cells/cm(2)) were plated and incubated for 72 h. The cell number was counted, the cell morphology was assessed by scanning electron microscopy and the cell metabolism was evaluated using methyltetrazolium assay. The statistical analysis of Kruskal-Wallis was used to determine if the scores obtained for the cell metabolism and number of cells were different at the 95% confidence level. In groups 1, 2, 3, 4, 5, and 6 the materials decreased the cell number by 74.5% 75.5%, 45.5%, 29.5%, 32.5%, and 88.5%, respectively. In groups 1, 2, 3, 4, and 5, the experimental GICs reduced the cell metabolism by 79%, 84%, 54%, 40%, and 42.5%, respectively. Despite the fact that all experimental materials were cytotoxic to the MDPC-23 cells, the GICs were the least cytotoxic. on the other hand, the RMGICs caused the highest cytophatic effects. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Clinical and microbiological performance of resin-modified glass-ionomer liners after incomplete dentine caries removal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of Ultrasonic Excitation on the Porosity of Glass Ionomer Cement: A Scanning Electron Microscope Evaluation

Background: Ultrasonic excitation (US) was applied to glass ionomer cement (GIC) during early set time to increase the advantageous properties of this material. Purpose: The aim of this in vitro study was to assess the inner porosity of GIC after US. Study design: A total of 16 specimens, for each material, were prepared from high-viscosity GIC Fuji IX GP, Ketac Molar, and Ketac Molar Easymix. Half of these specimens (n = 8) received 30 s of US during the initial cement setting. After completion of the material setting, specimens were fractured and observed by scanning electronic microscopy to quantitatively assay porosity inside the material using Image J software. Results: Statistical data analysis revealed that US reduced the porosity for all tested materials (P <= 0.05). The following reductions (expressed in percentages) were achieved: Fuji IX-from 3.9% to 2.8%; Ketac Molar Easy Mix-from 4.4% to 2.6%, and Ketac Molar-from 2.4% to 1.6%. Conclusion: Under the tested conditions, US was an effective method for porosity reduction inside the material. Microsc. Res. Tech. 74:54-57, 2011. (C) 2010 Wiley-Liss, Inc.

Influences of the insertion method in glass ionomer cement porosity

The aim of this study was to evaluate the presence of porosities inside the glass ionomer cement (GIC) after different techniques of material insertion. MATERIAL and METHOD: Specimens were prepared with high-viscosity GIC Ketac Molar Easymix and divided into three groups according to the insertion method: spatula (PI), Centrix injector (CI), and low-cost syringe (LCS). The specimens were fractured and observed with scanning electronic microscopy to quantitatively evaluate porosity inside the material using Image J Software. RESULTS: Statistical analysis, ANOVA application, and Tukey test to significance level of 5%, revealed that there was no statistical difference between the groups. CONCLUSION: Although the use of LCS has not decreased the porosity of the material, this insertion method is easy, accessible, and low cost, which makes it a viable alternative of use in the ART technique and in others bucal health programs. Microsc. Res. Tech., 2012. (c) 2012 Wiley Periodicals, Inc.

EFFECT of ULTRASONIC EXCITATION on THE MICROTENSILE BOND STRENGTH of GLASS IONOMER CEMENTS TO DENTIN AFTER DIFFERENT WATER STORAGE TIMES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pulp response after application of two resin modified glass ionomer cements (RMGICs) in deep cavities of prepared human teeth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mechanical and biological characterization of resin-modified glass-ionomer cement containing doxycycline hyclate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)