Effect of addition of bioactive glass (SiO2–CaO–P2O5–MgO-SrO) to glass ionomer and resin modified glass ionomer cement on dentin remineralization

Abstract

Intrudoction: Bioactive glass is a material with high biocompatibility, which by creating a biological response on its surface, causes the formation of a bond between itself and tissues. Due to its unique properties, in recent years, extensive studies have been conducted on the use of this substance in dentistry. Glass ionomers have many advantages, such as direct bonding with teeth, which allow effective restoration of decayed teeth. In addition, they have good biocompatibility properties, release and absorb fluoride, resulting in an antibacterial effect and fluorapatite remineralization. Unlike composites, their shrinkage during setting is also negligible. But despite their major advantages compared to other common restorative materials, their mechanical properties are still improving since their development. Considering the lack of studies in the field of adding bioactive glass to resin modified glass ionome, this study was conducted with the aim of investigating dentin remineralization by adding bioactive glass to glass ionomer. Materials and Methods: 30 premolars without decay were collected and then placed in thymol solution for one month for disinfection and then kept in saline solution at room temperature until the time of study. The surface enamel of the premolars was removed with a diamond disc and air spray, and the dentin was demineralized with ethyldiamine tetraacetic acid solution for 6 hours. The samples were randomly divided into 6 experimental groups based on the amount of bioactive glass and the type of glass ionomer, and each group contained 5 permolar: the first group contained glass ionomer in pure form, the second group contained ten percent of weight, and the third group contained twenty percent of weight bioactive glass. For resin modified glass ionomer, three groups were formed in the same way. The sol-gel method was used for the synthesis of bioactive glass. Glass ionomer powder and resin glass ionomer were mixed with bioactive glass separately for two minutes by ball milling. Then their powder and liquid were mixed according to the factory instructions. The mixed glass ionomer was poured into a mold to form a block. Then the blocks were approximated to the surface of the demineralized dentin, secured by orthodontic bands and kept in artificial saliva for two weeks. After this period, the blocks were separated and the surface of the dentin was washed with distilled water for 3 minutes. XRD and SEM tests were performed three times on the samples. Once before demineralizing the dentin, once after demineralizing the dentin, and the last time after keeping it in artificial saliva for two weeks, the test was performed on the samples and the remineralization of the dentin was checked. Results: In XRD analysis of the dentine surface, before and after contact with BAG, peaks are observed that indicate FAP and HAP crystals. These peaks decreased significantly after demineralization. In BAG20 groups, these peaks increased the most after contact. In statistical studies, the effect of time did not have a significant difference in the angle of 26, but it was significant in the angle of 32. The group effect was statistically significant (p-value<0.001) and GI20 and RMGI20 groups showed the most changes and GI0 and RMGI0 groups showed the least changes. The difference in remineralization between GI and RMGI was not statistically significant. Conclusion: Use of bioactive glass in weight percentages of 10 and 20 with glass ionomer and modified glass ionomer resin is effective in the process of dentin remineralization, and with the increase in the percentage of bioactive glass, the ability of dentin remineralization increases. There is no significant difference between the remineralization ability of GI and RMGI modified with bioactive glass.