The effect of adding silica nano particles on the compressive strength properties and the dimensional accuracy of type4 dental Stone

Abstract

Introduction: Dental stone is used in making dental prostheses such as full or partial dentures, fixed dentures or mobile orthodontic devices. In dentistry, especially in dental prostheses, gypsum products that are in the form of hemihydrate are used commonly. Considering the need to have high compressive strength and dimensional accuracy in dental casts, in this study, these properties were investigated by adding silica nanoparticles to dental stone type 4 plaster.

Materials and methods: In this study, silica nanoparticles (silicon dioxide) with percentages of 0.5, 1 and 2% are added to dental acetone. Dental stone without silica nanoparticles was used as a control group, 80 cylindrical samples with a height of 6 mm and a diameter of 3 mm for compressive strength testing and 40 samples with the help of a stainless steel mold with a diameter of 30 mm, a height of 6 mm and a thickness of 4 mm, which is a single structure. It is supported by a base with a diameter of 38 mm and a height of 30 mm and a circumferential shoulder on top of it with 3mm height and 4mm width. The prepared samples were examined in terms of compressive strength properties and dimensional changes. We used a universal testing machine to check the compressive strength and a stereomicroscope was used to check the dimensional accuracy.

Results: The addition of silica nanoparticles to plaster increases the dimensional accuracy, which requires at least 1% silica nanoparticles for this increase in dimensional accuracy, and there is no significant difference between the 1% and 2% groups. The compressive strength decreases with increasing concentration of silica nanoparticles, but this decrease is not significant compared to the compressive strength of the control group. In fact, in order to significantly reduce the compressive strength, silica nanoparticles should be added in higher concentrations to plaster powder.

Conclusion: Considering the great importance of dimensional accuracy in the fabrication and matching of prostheses, as well as the lack of significant effect of adding silica nanoparticles on compressive strength, considering the significant increase in dimensional accuracy after adding silica nanoparticles, the use of adding nanoparticles to dental stone plaster Type 4 can be added in dentistry.