Comparative evaluation of compressive and flexural strength, fluoride release and bacterial adhesion of GIC modified with CPP-ACP, bioactive glass, chitosan and MDPB

Background. This study evaluated the incorporation of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), calcium sodium phosphosilicate bioactive glass (BAG), chitosan (CH), and methacryloyloxydodecylpyridinium bromide (MDPB) on the compressive and flexural strength, fluoride (F‒ ) release, and bacterial adhesion of conventional glass-ionomer cement (C-GIC).

Methods. Modifications were implemented by adding CPP-ACP, BAG, and CH to the glass powder, while MDPB-GIC was prepared by incorporating MDPB to the liquid of C-GIC. Custom-made molds were used for specimen preparation. Compressive and flexural strengths were evaluated using a universal testing machine. F‒ release was calculated with Erichrome cyanide reagent, using UV-spectrophotometry, at two time intervals of 24 hours and seven days. For bacterial adhesion, the test specimens were exposed to the bacterial suspension of Streptococcus mutans and Lactobacillus acidophilus for 4 hours, and the adherent bacteria were quantified using colorimetry as the optical density (OD).

Results. The incorporation of MDPB increased the flexural strength of C-GIC, with no effect on its compressive strength. CH significantly improved the compressive and flexural strength; modifications with CPP-ACP, BAG, and MDPB significantly improved the flexural strength of C-GIC. While MDPB-GIC released significantly higher F‒ at 24 hours, CPP-ACP- and BAG-modified GICs were comparable to C-GIC on day 7. C-GIC exhibited the highest bacterial adhesion, and MDPB-GIC showed the least. The data were analyzed with one-way (ANOVA), and pairwise comparisons were made with Tukey HSD tests.

Conclusion. Hence, it can be concluded that the incorporation of CPP-ACP, BAG, and CH improved the mechanical properties of C-GIC, whereas MDPB improved the resistance of C-GIC to bacterial adhesion.