In vitro interactions between lactic acid solution and art glass-ionomer cements

Abstract

Objectives:Production of acids such as lactic acid contributes to establish a cariogenic environment that leads to dental substrate demineralization. Fluoride plays an important role in this case and, as fluoride-releasing materials, glass-ionomer cements are expected to contribute to minimize deleterious reactions. This study evaluated interactions of glass-ionomer cements used in atraumatic restorative treatment (ART-GICs) with an aqueous lactic acid solution, testing the null hypotheses that no changes occur in the pH of the solution or on the surface roughness and mass of the ART-GICs when exposed to lactic acid solution over a 6-week period.Material and Methods:Ketac Molar, Fuji IX, Vitro Molar and Magic Glass were tested, and compared to Filtek Z250 and Ketac Fil Plus as control groups. Six specimens of each material were made according to manufacturers' instructions. The pH of the solution and roughness and mass changes of each specimen were determined over 6 weeks. Each specimen was individually stored in 2 mL of 0.02 M lactic acid solution for 1 week, renewing the solution every week. pH of solution and mass of the specimens were monitored weekly, and surface roughness of the specimens was assessed before and at the end of the 6-week acid challenge. pH and mass data were analyzed statistically by repeated measures using one-way ANOVA and Tukey's post-hoc tests for each material. Paired t-tests were used for roughness analysis. Tukey's post-hoc tests were applied to verify differences of final roughness among the materials. Significance level was set at 5%.Results:The null hypotheses were partially rejected. All materials were able to increase the pH of the lactic acid solution and presented rougher surfaces after immersion, while mass change was minimal and generally not statistically significant.Conclusions:These findings can be helpful to predict the performance of these materials under clinical conditions. A protective action against the carious process with significant surface damage due to erosion may be expected.

Compressive Strength of a Glass Ionomer Cement Under the Influence of Varnish Protection and Dietary Fluids

“…Studies of surface properties show a higher probability of significant influence from storage media on the glass ionomer cement, as observed by Lima et al (7) and Braga et al (19). On the other hand, studies that evaluated the effect of certain storage media on the internal structure of glass ionomer cements showed that the differences were not significant, as observed by Wang et al (16) and in this study.…”

“…This study evaluated the hypothesis that dietary fluids have an effect on the compressive strength of a conventional glass ionomer cement, with or without fluoride varnish protection. Compressive strength is an important property for restorative materials, as it represents tensions that occur during chewing (16). Moreover, Lima et al (7) have reported that there is little specific information regarding the action of fluids on glass ionomer cements, which justified the need for investigation.…”

“…Corroborating this information, Braga et al (19) observed that acidic beverage ingestion followed by brushing causes degradation of the resin-modified glass ionomer. Wang et al (16) observed that the Young's modulus of glass ionomer cement was not significantly changed after immersion in a lactic acid solution. This is similar to the results obtained in our study.…”

Evaluación de la resistencia a la erosión ácida de dos ionómeros de vidrio utilizados en la técnica restaurativa atraumática (TRA), modificados con un antibiótico

“…El ionómero de vidrio es un material que actualmente se utiliza en tratamientos restauradores en molares temporales y molares permanentes jóvenes, por lo que se espera que conserve propiedades importantes como la resistencia a la erosión ácida. [13][14][15] Es sabido que en un ambiente bucal con alto índice de caries el pH se encuentra disminuido, lo que trae como consecuencia la acelerada pérdida de superficie del material de restauración, acortando así el tiempo de vida del mismo.…”

A ação de sucos de frutas sobre materiais restauradores utilizados em lesões cervicais não cariosas

“…A absorção de água e o comportamento de solubilidade dos materiais resinosos dependem da composição da matriz (Ortengren et al, 2001b). O HEMA é um componente hidrófilo das matrizes à base de metacrilato, por esta razão, materiais que apresentam maior percentual na sua composição tendem a absorver mais água (Wang et al, 2009).…”