Purpose: this study compared the translucency of zirconia specimens veneered with different veneering techniques, and compared the change in translucency after aging. Materials and methods: Fifty slice specimens (0.50 ± 0.01mm thick) were fabricated of IPS e.maxZirCAD core material, and ZL1 IPS e.maxZirLiner (0.10-mm thick) was layered. The specimens were randomly divided into five groups (n=10/group). Group Ι (traditional layering technique) was veneered (0.60 mm) by condensing and sintering IPS e.max Ceram low-fusing nano-fluorapatite veneering porcelain; Group ΙΙ (High translucency press on technique) was veneered (0.60 mm) by heat-pressing HT IPS e.maxZirPressfluorapatite glass-ceramic ingots; Group ΙΙΙ (Low translucency press on technique) was veneered (0.60 mm) by heat-pressing LT IPS e.maxZirPressfluorapatite glass-ceramic ingots; Group ΙѴ (High translucency CAD-ON technique) was veneered (0.60 mm) by HT IPS e.max CAD lithium disilicate glass ceramic blocks and GroupѴ (Low translucency CAD-ON technique) was veneered (0.60 mm) by LT IPS e.max CAD lithium disilicate glass ceramic blocks. CIE (L∗, a∗, b∗) parameters were measured and translucency was calculated for each veneering technique before and after aging according to the following equation: TP=[(L∗ B-L∗ W)2 + (a∗ B-a∗ W)2 + (b∗ B-b∗ W)2]1/2. One-way analysis of variance (ANOVA) combined with Bonferroni's post-hoc test and Paired t-test were used to analyze the data (α=0.05). Results: Statistical analysis utilizing One-way ANOVA showed that, pressing technique had higher translucency than build-up and CAD on techniques. There was a significant difference between the three techniques except for the low translucency Pressing and CAD on techniques when compared with the build up after aging. Using Paired-t test to determine the effect of aging, a significant decrease of translucency was found in all techniques after aging except for the low translucency Pressing and CAD on techniques. Conclusion: Veneering zirconia with both layering and pressing techniques produced more translucent samples than with CAD-ON veneering technique. Aging caused a decrease in translucency of all samples.
El-Agwany M, Wahsh MM, Morsi TS. Effect of veneering techniques and subsequent aging on translucency of bilayered zirconia. Future Dental Journal. 2020; 4(2):274-278.