Evaluation the physicochemical properties, solubility and antimicrobial effect of cement containing curcumin nanocrystals against three bacterial species of S. mutans, S. aureus and E. coli

Abstract

Cements, such as glass ionomer cement, are commonly used as sealants between teeth and crown. However, there is still the possibility of bacterial microleakage, which in turn causes secondary caries, thus compromising the longevity of the repair. The aim of this in vitro study was to evaluate the physicochemical, solubility and antimicrobial properties of glass ionomer cement containing curcumin nanocrystals against three bacterial species of Escherichia coli, Staphylococcus aureus and Streptococcus mutans. Materials and Methods: Ionomer glass cement (GC Fuji I / Itabashi-CHO, Tokyo, Japan) was physically mixed with curcumin nanocrystals powder with an average particle size of 95 nm, at weight percentages of 80 to 20 and 70 to 30. Mixing was continued until the ingredients were completely mixed. The prepared powders were then subjected to physicochemical studies. Fourier transmission infrared spectroscopy (FTIR) was used to investigate possible bonds and identification of functional groups, X-ray diffraction to examine crystallinity, scanning electron microscopy ((SEM, TESCAN, Warrendale, PA) to study the morphology of materials and their mixation state. The standard concentration curcumin in cement was prepared using a spectrophotometer (UV, Shimadzo, Japan) and the release pattern of curcumin from the cement matrix structure was evaluated using drug dissolution devices (USP apparatus II, paddle stirrer) and UV spectrophotometer. For microbial evaluation of cement containing nano-curcumin, disk diffusion method was used against Streptococcus mutans, Staphylococcus aureus, Escherichia coli. Results were reported as an average of three measurements (± standard deviation). Shapiro-Wilk test was used to evaluate the normality of the data. One-way analysis of variance was used to compare the results of the mean growth inhibition zone between bacteria in the two cement groups separately. Graph Pad version 9 software was used for data analysis. The probability value less than 0.05 was considered significant. Results: The results of electron microscope morphological evaluations show that the cement and the nanocurcumin are mixed uniformly. The release of curcumin from cement was a two-stage release, 40% of which continued in the first two days and the rest slowly until the 14th day. No new interactions were observed in the FTIR and XRD spectra of the studied materials, which is the reason for the physical mixing of these two materials. The results of antimicrobial evaluations in our study showed that both types of cement 20 and 30% curcumin had antimicrobial properties. These two substances were able to inhibit the growth of all three selected bacteria. Statistical analysis showed that the order of amount for growth inhibition in 20% and 30% cements was Escherichia coli, Staphylococcus aureus and Streptococcus mutans, respectively. The difference in the amount of growth inhibition zone between bacteria was significant for both 20% and 30% cements (P> 0.005). Also, the difference the growth inhibition zone between 20% and 30% cements was significant for Escherichia coli (P = 0.04) but not significant for the other two bacteria (P = 0.2, P = 0.1). Conclusion: The results showed that the use of ionomer glass cement containing curcumin can be effective in controlling bacterial infection. The use of these nanoparticles in optimal formulation and appropriate concentration can replace the use of chemical antimicrobials in the future or to reduce bacterial resistance along with them. However, according to the results of water absorption and solubility, it seems that more physico-mechanical tests are needed on the cement containing curcumin. Extensive cellular, animal and clinical studies are also needed to prove the true and clinical function of this new substance.