Synergistic Effects Of Cellulose Nanocrystals And Titanium Dioxide On The Properties Of Glass-ionomer Cement

Glass-ionomer cement?GIC?is a common dental restoration material in clinical practice.This is attributed to the very unique properties of GICs,such as good adhesion to tooth structure,excellent anticariogenic properties,thermal compatibility with tooth hard tissue,and low cytotoxicity and so on.However,the numerous disadvantages of GICs,such as poor wear resistance,low mechanical strength,high porosity,and poor polishing properties,have restricted their usage.Therefore,modified glass ionomer cement has become a research hotspot.Objective:The aim of this study was to evaluate if the co-doping addition of titanium dioxide?TiO₂?nanoparticles and sisal cellulose nanocrystals?CNCs?would improve the physical and mechanical properties,antimicrobial effects,and cytotoxicity of a conventional GIC.Methods:Test samples were prepared and submitted to mechanical tests,such as compressive?CS?,surface microhardness,wear resistance,solubility,and shear bond strength?SBS?and morphology,chemical structure and surface element of the composites were characterized by scanning electron microscopy?SEM?,energy-dispersive X-ray spectroscopy?EDS?,and Fourier-transform infrared?FTIR?spectroscopy.Antibacterial Antimicrobial activity was evaluated against Staphylococcus aureus and Candida albicans.Cytotoxicity experiments were evaluated using L-929 fibroblasts cells by MTT and cell morphology observations.Data were assessed using ANOVA and Tukey's test.After homogeneity of variance test,one-way ANOVA was used to compare the differences between the mean of each group.The pairwise comparisons were compared by Turkey HSD test.The test level was?=0.05.Results:Compared with the control group,the co-doped group demonstrated an increased compressive strength of 18.9%,an increased enamel shear bond strength of 51%,the dissolution decreased by 18.3%,the volume wear rate was reduced by 5.2%.And there was no significant difference in surface hardness.The antibacterial effects against Staphylococcus aureus and C.albicans were all increased to 92.3%.Cytotoxicity experiments showed that the co-doped group had a slight negative effect on the viability of the L-929 cells.Conclusion:The physical properties of the GIC group co-doped with 2 wt%TiO₂nanoparticles and 1wt%CNC were significantly improved.Antimicrobial activities were all improved?C.albicans and Staphylococcus aureus?.