Nanomechanical Comparison of Commonly Used Dental Crown Cements to a Newly Developed One

Abstract

The main goal of nanoindentation tests is to obtain elastic modulus and hardness of the specimen material from load-displacement measurements. With this study, it was aimed to establish a quantitative relationship between the nanomechanical properties of commonly used dental cements in comparison to a newly developed crown cement and to predict its performance potential. Nanomechanical properties of polycarboxylate cement (PCC), glass-ionomer cement (GIC), dual-cure self-adhesive cement (SAC) and a newly developed glass-carbomer cement (GCC) were investigated by nanoindentation tests. All samples were fabricated according to their respective manufacturer's instructions. Available damage on the surface due to manipulation was removed by grinding with 1200, 2400 and 4000 grit sandpaper, and then polishing on 6, 3, and 1 µm diamond-lap-wheel was performed. Nano-mechanical measurements were done using nanoindenter machine with resolution less than 1 nN and displacement resolution of 0.04 nm. Berkovich diamond indenter tip was used for the nanoindentation tests. For each indentation, a set of nanoindentation tests at least on 6 different locations per specimen surface were performed to obtain more representative mean results. Indentation test load-displacement curves were analysed using Oliver-Pharr method, and one-way ANOVA or Kruskal-Wallis test, following Kolmogorov-Smirnov and Shapiro-Wilk, was used to compare the results. Nanohardness (Hnano) values were 0.52±0.25, 0.45±0.18, 1.03±0.82 and 0.43±0.18 GPa for GIC, GCC, PCC, and SAC, respectively. Reduced elastic modulus (Er) values were 9.51 ± 6.17, 11.77 ± 5.04, 27.37 ± 20.61, 10.33 ± 5.08 GPa for GIC, GCC, PCC, and SAC, respectively. There was no statistical difference between the tested materials. PCC was the hardest, and GIC was the least hard material, whereas the newly developed GCC was the second, in terms of Hnano, before SAC. PCC also had the highest Er mean, compared to the other dental crown cements, suggesting lower elastic properties. SAC was more elastic than GCC and less elastic than GIC. GCC had the second highest Er, standing closer to SAC and GIC. Within the limitations of the current study, it can be concluded that the newly developed glass-carbomer cement is comparable to the other tested commonly used dental crown cements, regarding Hnano and Er.

Comparison of restorative materials and surface alterations after prebiotic and probiotic beverages: A nanoindentation and SEM study

“…To record the topographic images, the nanoindenter was also operated in scanning probe mode. Indentation test load-displacement (depth) curves were analyzed using Oliver-Pharr method (Kale et al, 2017).…”