The addition of silica nanoparticles on the mechanical properties of dental stone

Comparative Evaluation of Compressive and Diametral Tensile Strength in Die Stone Reinforced With Different Types of Nanoparticles: An In Vitro Study

AIM

To investigate the effect of different types of nanoparticles on the compressive strength (CS) and diametral tensile strength (DTS) of type IV dental stones.

MATERIALS AND METHODS

A total of 100 specimens were made from the mould for all five groups. Four commercially available nanoparticles (aluminium oxide (Al2O3), silicon dioxide (SiO2), zinc oxide (ZnO), and zirconium oxide (ZrO2)) were used in this study in a concentration of 10%. CS and DTS tests were performed in a universal test machine. The data were statistically analysed using ANOVA and Student's t-test.

RESULTS

The interaction between nanoparticles and the type of dental stone was found to be statistically significant (p < 0.05). CS and DTS values decreased by adding all four nanoparticles. The lowest CS and DTS were observed in 10% ZnO nanoparticles when added to type IV dental stone.

CONCLUSION

It was concluded that the addition of nanoparticles (Al2O3, SiO2, ZnO, and ZrO2) to die stone significantly decreased the CS and DTS for all groups. Among all groups, the incorporation of 10% ZrO2 nanoparticles (group E) to die stone showed significantly less decrease in CS and DTS compared to Al2O3, SiO2, and ZnO. Incorporation of ZnO nanoparticles, on the other hand, showed a significantly more amount of decrease in the CS and DTS compared to Al2O3, SiO2, and ZrO2.

Effect of Adding Silica Nanoparticles on the Physicochemical Properties, Antimicrobial Action, and the Hardness of Dental Stone Type 4

This study was conducted to investigate the effect of adding silica nanoparticles on the physicochemical properties, antimicrobial action, and the hardness of dental stone type 4. Dental stone type 4 powder was physically mixed with nanoparticle powder at weight percentages (0, 0.5, 1, and 2 percent). The required amount of powder was added to water according to the manufacturer's instructions. The prepared set materials were subjected to the physicochemical studies; Fourier transmission infrared spectroscopy (FTIR) was taken up to investigate the functional groups and X-ray diffraction (XRD) was used to evaluate the crystallinity. Also, scanning electron microscopy (SEM) was used to examine the morphology of the prepared samples. Agar diffusion test was carried out for the prepared samples against the Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) to test the average growth inhibition zones. Finally, the Vickers surface hardness test was performed for each group using a hardness tester. The adding silica nanoparticles to dental stone type 4 increased the diameter of inhibition zones for the groups in both bacteria significantly (p < 0.05). The results showed that adding silica nanoparticles to dental stone type 4 increased the diameter of inhibition zones for the groups in both bacteria significantly (p < 0.0001). There was a significant difference between all groups and the 0% group in both bacteria (p < 0.0001). Besides, the adding of silica nanoparticles to dental stone type 4 increased the surface hardness significantly (p = 0.0057) without any effect on physicochemical properties. The 0% and the 0.5% groups had significant differences with the 2% group (p = 0.0046 and p = 0.0205 respectively). Then, at least 2% silica nanoparticles are needed for a significant increase. Clinical trials are needed to enlarge for dental stone type 4 containing silica nanoparticles in the future.

Influence of preparation method on mechanical characteristics of plaster

Introduction: Plaster is widely used in dentistry for the production of master casts, as a binder in investment materials and as an auxiliary material in the laboratory stages of denture production. Due to its brittleness, there is a constant need to improve its mechanical properties. In this regard, in the research we started from the assumption that increasing the proportion of powder during the preparation of plaster improves its mechanical properties. The aim of this research wasto determine the significance of the change in the ratio of powder and liquid to the mechanical characteristics of plaster (compressive strength). Material and methods: Three types of plaster were used in the research: type 2, 3 and 4. For each type of plaster, three samples were made with different ratio of powder and amount of water (n = 9). After 24 hours, the samples were analyzed at the Faculty of Mechanical Engineering in Niš, on a universal testing machine. Results: Plaster type 2 showed the lowest values of compressive strength, and higher values of types 3 and 4, regardless of the ratio of plaster powder and water. As the powder content increased, the compressive strength of the samples increased. Conclusion: In order to improve the compressive strength, the proportion of powder in the liquid phase can be increased during the preparation of the material without visible changes in its structure.