Experimental glass ionomer cement modified by the incorporation of nanoselenuim: antibacterial activity, cytocompatibility and compressive strength

The use of restorations with antibacterial activity has become mandatory to control secondary caries, especially in atraumatic restorative treatment (ART). Therefore, this study was conducted to enhance the antibacterial activity of conventional glass ionomer cement (GIC) by adding nanoselenium (NSe) and to assess the impact on its cytocompatibility and compressive strength. NSe was prepared and characterized, and its minimum inhibitory concentration (MIC) against Streptococcus mutans (S. mutans) was determined via the broth microdilution technique. Based on the MIC, grouping was performed. Group I included unmodified GIC samples mixed with water, and groups II–IV included GIC samples mixed with three different concentrations (75, 112.5, and 150 ppm, respectively) of the NSe suspension. Antibacterial activity against S. mutans was assessed via an agar disc diffusion test over four time intervals (24, 48, 72 h, and 7 days). The cytocompatibility of 100% and 10% concentrations of the sample extract was evaluated via a sulforhodamine B (SRB) assay against oral epithelial cells. Additionally, compressive strength testing was performed according to ISO 9917-1 using a universal testing machine. Regarding antibacterial activity, group IV presented significantly higher values than the other groups, followed by group III, at all time intervals. For cytocompatibility, group II had higher values of cell viability at both concentrations. For all groups, the 10% concentration had significantly higher values of cell viability than the 100% concentration. Moreover, none of the groups showed a statistically significant difference in compressive strength. The addition of NSe at concentrations up to 150 ppm resulted in extended antibacterial activity against S. mutans for up to 7 days without affecting its compressive strength. Furthermore, the addition of NSe at a low concentration, such as 75 ppm, increased the viability of oral epithelial cells.