To Evaluate and Compare the Effect of Commercially Available Model Hardening Agent on Surface Hardness and Surface Roughness of Refractory Investment Materials: An In-Vitro Study

Abstract

Background: Various studies are conducted to evaluate the effect of hardening agent on surface hardness

of refractory investment material but these studies do not evaluate the amount of load and depth at which

maximum hardness is anticipated. So, the present study was conducted to evaluate the effect of hardening

agent on the surface hardness of dental refractory investment material when treated with hardening agent at

varying degree of load and depth. Materials and methods: The commercially available phosphate-bonded

refractory investment material (Adentatec-Vest PA, Adentatec GmbH, Germany) and hardening agent

(Kalthärter cold hardener, Dentaurum GmbH & Co. Deutschland) were used in this study. The specimens

were fabricated and divided into two groups: Group A: specimen without hardening treatment; Group B:

specimen with hardening treatment. Surface hardness test was performed with the use of a nanoindenter (NT

Berkovich indenter); while surface roughness test was measured with Surfcom-130A using an electrically

operated stylus arm. The data were tabulated and analyzed using t-test for both the surface hardness and

surface roughness parameters with p-value <0.05 was considered significant. Results: Both surface

roughness (p=0.043) and surface hardness (p= 0.017) of group A and group B specimens were comparable

and have shown with significant difference. Conclusion: The hardening treatment is effective on decreasing

surface roughness and improving surface hardness of phosphate-bonded refractory investment material.