In Vitro Cytotoxicity Evaluation of Novel Nano-Hydroxyapatite-Silica Incorporated Glass Ionomer Cement

INTRODUCTION: Glass Ionomer Cements (GIC) are among the most popular restorative materials, but their use in dentistry is limited due to their physical properties. The hardness of GIC was improved by incorporation of nano-hydroxyapatite-silica into GIC, to expand its applicability.

AIM: To evaluate the cytotoxic effects of nano-hydroxyapatite-silica incorporated glass ionomer cement (HA-SiO2-GIC) on human Dental Pulp Stem Cells (DPSC) and compare it with conventional GIC and resin modified GIC.

MATERIALS AND METHODS: Material extracts of Fuji IX, Fuji II LC and HA-SiO2-GIC were prepared into seven serial concentrations and applied to 96-well-plates seeded with DPSC. The 96-well-plates were incubated for 24 and 72 hours. The morphology of DPSC was observed under the inverted phase contrast microscope, and the cell viability was determined using MTT assay at both time intervals. Kruskal-Wallis test was performed for statistical analysis.

RESULTS: At maximum concentration, DPSC appeared fewer in number, but the normal spindle morphology was maintained in all groups except for Fuji II LC. At lower concentrations, DPSC appeared normal and more confluent in all groups. The cytotoxic effects of all groups were dose dependent. Fuji IX demonstrated the lowest cytotoxicity, followed by HA-SiO2-GIC. Fuji II LC demonstrated the highest cytotoxicity. The difference was significant between all groups at 200 mg/ml concentration (p<0.05). At concentration <100 mg/ml, cytotoxicity of HA-SiO2-GIC was comparable to that of Fuji IX and lower than that of Fuji II LC.

CONCLUSION: HA-SiO2-GIC showed a favourable cytotoxicity response and thus holds promise as a future potential restorative material in clinical dentistry.