IADR Abstract Archives
Brittleness Index and Vickers Hardness Evaluation of Different CAD/CAM Materials
Objectives: CAD/CAM ceramic restorations are becoming increasingly popular worldwide once chair-side machines can delivery restorations on a single dental appointment. The newly emergent leucite-glass ceramic and lithium disilicate ceramic blocks have acquired research interest due to better mechanical and aesthetic properties, when compared to the feldsphatic ceramic. The aim of this study was to evaluate Brittleness index and Vickers hardness of different CAD/CAM materials and the correlation between then.
Methods: Thirty-nine CAD/CAM blocks from three different companies were used: Vitablocs Mark II (Vita Zahnfabrik, Essen, Germany) as a control group, IPS e.max CAD (Ivoclar Vivadent, Schaan, Liechtenstein) and IPS Empress CAD (Ivoclar Vivadent, Schaan, Liechtenstein). Blocks slices with 14x10x3mm (LxWxH) were made using a Diamond saw machine then regularized using a grinding and polishing device. For both tests, each specimen surface was divided in four quadrants. Brittleness index was calculated by measuring the crack along the vertex of the indentation on the same direction of the diagonal 1. Vickers hardness was calculated by measuring the diagonal 1 and 2 distances and analyzed by the micro hardness software on the tester machine. One-way ANOVA was performed using SPSS 22.0 software with post-hoc Tukey’s test with 95% confidence.
Results: A Levene’s test for homogeneity of variances was used (p>0.05) and satisfied, also Shapiro-Wilk’s test (p>0.05). The results of Vickers hardness showed that IPS e.max CAD group (697.71±16.50) is the hardest material, while the IPS Empress CAD group (585.83±20.94) showed the lowest values. For Brittleness index IPS e.max group (2.54±0.17) demonstrate higher values among the others. The calculation of Pearson’s correlation showed a positive relationship between Vickers hardness and Brittleness index.
Conclusions: The Vickers hardness and Brittleness index of IPS e.max CAD were significantly higher than those two materials tested.
Methods: Thirty-nine CAD/CAM blocks from three different companies were used: Vitablocs Mark II (Vita Zahnfabrik, Essen, Germany) as a control group, IPS e.max CAD (Ivoclar Vivadent, Schaan, Liechtenstein) and IPS Empress CAD (Ivoclar Vivadent, Schaan, Liechtenstein). Blocks slices with 14x10x3mm (LxWxH) were made using a Diamond saw machine then regularized using a grinding and polishing device. For both tests, each specimen surface was divided in four quadrants. Brittleness index was calculated by measuring the crack along the vertex of the indentation on the same direction of the diagonal 1. Vickers hardness was calculated by measuring the diagonal 1 and 2 distances and analyzed by the micro hardness software on the tester machine. One-way ANOVA was performed using SPSS 22.0 software with post-hoc Tukey’s test with 95% confidence.
Results: A Levene’s test for homogeneity of variances was used (p>0.05) and satisfied, also Shapiro-Wilk’s test (p>0.05). The results of Vickers hardness showed that IPS e.max CAD group (697.71±16.50) is the hardest material, while the IPS Empress CAD group (585.83±20.94) showed the lowest values. For Brittleness index IPS e.max group (2.54±0.17) demonstrate higher values among the others. The calculation of Pearson’s correlation showed a positive relationship between Vickers hardness and Brittleness index.
Conclusions: The Vickers hardness and Brittleness index of IPS e.max CAD were significantly higher than those two materials tested.