Investigating dental Glass ionomer cement surface hardness and shear bond strength after incorporate it with Chlorhexidine

Abstract

This research project aims to investigate the impact of integrating chlorhexidine (CHX) into glass ionomer cement (GIC) on its surface hardness and shear bond strength. GIC samples were modified with different concentrations of CHX to achieve this objective. The surface hardness of the control and modified samples were measured using the Vickers hardness test. Shear bond strength (SBS) was evaluated using the universal testing machine and shearing jig, employing zirconia and hydroxyapatite (HA) as a substrate. The null hypothesis assumed there was no significant difference on surface hardness and SBS after adding CHX into the GIC. One control group and three variables were examined in this study: the control group (was composed of GIC without the addition of CHX) and the three trial groups were GIC with the addition of 5%, 10% and 20% concentrations of CHX, respectively. To confirm the presence of CHX in the modified samples, Fourier transform infrared spectroscopy (FTIR) analysis was utilised. The results of FTIR shows different peaks for the control group and characteristic peaks of CHX, which represents the presence of CHX in the modified samples. These peaks were not present after 24 hours, suggesting the leaching of CHX. A one-way ANOVA single factor analysis and Tukey’s test indicated significant differences in surface hardness after incorporating CHX into GIC. In terms of SBS, increases of mean values were observed in all modified groups. However, ANOVA single factor analysis indicated no significant difference between the GIC control group and the modified groups with different CHX concentrations (p-value > 0.05) when using zirconia and HA as a substrate. This study concluded that the null hypothesis was partially rejected, because the surface hardness was affected by adding CHX; possible applications of this modified GIC include temporary luting cement or interim restoration between root canal treatment, as of CHX is presence for a short time. Further investigation is needed to evaluate other mechanical properties and antimicrobial activity.