Application of reference point indentation for micro-mechanical surface characterization of calcium silicate based dental materials

Abstract

The objective of this study was to elucidate micromechanical properties of Biodentine and two experimental calcium silicate cements (CSCs) using Reference Point Indentation (RPI). Biomechanical characteristics of the cement type and the effects of a radiopacifier, liquid components, acid etching treatment and bioactivation in simulated body fluid (SBF) were investigated by measuring the microhardness, average unloading slope (Avg US) and indentation distance increase (IDI). Biodentine had a greater microhardness than the experimental CSCs, while the Avg US and IDI values were not significantly different among investigated materials. There was a statistically significant difference in microhardness and IDI values between pure CSCs and radiopacified cements (p < 0.05). Micromechanical properties were not affected by different liquid components used. Acid-etching treatment reduced Biodentine's microhardness while cements' immersion in SBF resulted in greater microhardness and higher IDI values compared to the control group. Clearly, the physiological environment and the cements' composition affect their surface micromechanical properties. The addition of calcium chloride and CSCs' immersion in SBF are beneficial for CSCs' micromechanical performance, while the addition of radiopacifiers and acid etching treatment weaken the CSCs' surface. Application of RPI aids with the characterization of micromechanical properties of synthetic materials' surfaces.

Surface Microhardness and Roughness Properties of Biodentine

“…Only one previous study evaluated the microhardness of Biodentine, but the study examined only the effects of EDTA and acids on the microhardness of the material. 12 The study found that physical properties of Biodentine were weaker after EDTA treatment, which was in contrast to the findings in the present study. The discord between our results and those of the previous study may be related to differences in test methods (Vickers microhardness test versus reference point indentation).…”

Effect of different root canal irrigants on surface roughness and microhardness of Biodentine combined with triple antibiotic paste: An in vitro study

“…Similar to the present study, Antonijević et al . [ 17 ] showed that the microhardness of Biodentine was reduced after being treated with 17% EDTA. This is because 17% EDTA has a strong chelating impact, which normally affects the microhardness of Biodentine over an extended period which is also supported by Wang et al .,[ 18 ] who reported that solutions with acidic pH such as EDTA weaken the microhardness of MTA.…”

Physico-chemical and biological properties of dental calcium silicate cements - literature review

“…The study revealed significant difference in microhardness and indentation values between pure CS cements, which demonstrated better features and radio pacified cements. Micromechanical properties were not affected by using different liquid components [64]. When adding different radiopacifiers to CS cements, engineers should be careful having in mind that some radiopaque agents (BaSO4 and CHI3) result in different radiopacities of the final mixture on dental film and digital sensor [65].…”