IADR Abstract Archives
Flexural Strength, Translucency of CAD/CAM Zirconia Blocks Following Speed Sintering
Objectives: To compare the translucency and strength of CAD/CAM zirconia blocks (with traditional and speed sintering) to lithium disilicate.
Methods: Specimens were sectioned from unsintered CAD/CAM zirconia blocks for flexural strength (16mmx4mmx1.2mm) and translucency (1mmx4mmx4mm). Three zirconia materials were tested with varying sintering times Kuraray Noritake KATANA Zirconia Block STML enamel layer NW shade (7hr, 30min and 18min), Zirkon Zahn Prettau Anterior (7hr and 30min), Tosoh Zpex Smile (7hr and 30min). 30min or 18min zirconia specimens were sintered in SpeedFire furnace (Dentsply Sirona) and other samples were sintered in a conventional zirconia sintering furnace (Noritake KATANA F-1). Ivoclar Vivadent IPS e.max CAD LT shade BL1 blocks were sectioned and crystallized with Noritake KATANA F-1 (25min). Three-point bend flexural strength specimens were polished with 400grit SiC paper. Translucency specimens were polished with 2000grit SiC paper. Three-point bend flexural strength specimens (n=10) were tested in a universal testing machine on 14mm separated supports and loaded to failure at 1mm/min. Translucency specimens were measured in a Color-i7 spectrophotometer (X-Rite, Grand Rapids, MI). Translucency parameter was calculated with the deltaE 2000 for L*a*b* values measured against white and black backgrounds. Contrast ratio was measured with internal software. Data were analyzed with 1-way ANOVA and Tukey post-hoc analysis (alpha=0.05)
Results: There were significant differences between materials for translucency parameter, contrast ratio, and flexural strength (p<.05). Materials with different letters in each column are statistically different.
Conclusions: Two of the zirconia materials (Prettau Anterior and Zpex Simle) became less translucent and less strong using a shortened sintering time. All zirconia materials were stronger but less translucent than IPS e.max CAD with traditional sintering times. With shortened sintering times, only KATANA Zirconia Block STML retained a higher strength than IPS e.max CAD. The translucencies of the different zirconia should not be compared as the Zpex Smile did not have color pigments.
This study was partially supported by a research grant from Kuraray Noritake Dental Inc.
Methods: Specimens were sectioned from unsintered CAD/CAM zirconia blocks for flexural strength (16mmx4mmx1.2mm) and translucency (1mmx4mmx4mm). Three zirconia materials were tested with varying sintering times Kuraray Noritake KATANA Zirconia Block STML enamel layer NW shade (7hr, 30min and 18min), Zirkon Zahn Prettau Anterior (7hr and 30min), Tosoh Zpex Smile (7hr and 30min). 30min or 18min zirconia specimens were sintered in SpeedFire furnace (Dentsply Sirona) and other samples were sintered in a conventional zirconia sintering furnace (Noritake KATANA F-1). Ivoclar Vivadent IPS e.max CAD LT shade BL1 blocks were sectioned and crystallized with Noritake KATANA F-1 (25min). Three-point bend flexural strength specimens were polished with 400grit SiC paper. Translucency specimens were polished with 2000grit SiC paper. Three-point bend flexural strength specimens (n=10) were tested in a universal testing machine on 14mm separated supports and loaded to failure at 1mm/min. Translucency specimens were measured in a Color-i7 spectrophotometer (X-Rite, Grand Rapids, MI). Translucency parameter was calculated with the deltaE 2000 for L*a*b* values measured against white and black backgrounds. Contrast ratio was measured with internal software. Data were analyzed with 1-way ANOVA and Tukey post-hoc analysis (alpha=0.05)
Results: There were significant differences between materials for translucency parameter, contrast ratio, and flexural strength (p<.05). Materials with different letters in each column are statistically different.
Conclusions: Two of the zirconia materials (Prettau Anterior and Zpex Simle) became less translucent and less strong using a shortened sintering time. All zirconia materials were stronger but less translucent than IPS e.max CAD with traditional sintering times. With shortened sintering times, only KATANA Zirconia Block STML retained a higher strength than IPS e.max CAD. The translucencies of the different zirconia should not be compared as the Zpex Smile did not have color pigments.
This study was partially supported by a research grant from Kuraray Noritake Dental Inc.