The Influence Of Post-and-cores On The Color Of Two Kinds Of All Ceramic Restoration

Objective:The present study is to make research on the color variation of two kinds of all ceramic core material and veneered core material on the resin, Ni-Cr alloy, opaque veneered Ni-Cr alloy and glide Ni-Cr alloy background. Studying the impact of different post-and-cores on the color of two kinds of all ceramic restoration can provide guidance for the clinical use. Method:In this study, we made background specimens simulating the post-and-core of resin, glide Ni-Cr alloy, opaque veneered Ni-Cr alloy and Ni-Cr alloy, overlaid the In-Ceram Alumina and IPS-Empress II samples on these background specimens, and measured the shifts in color with PR-650 spectrophotometer. The instrument should be correct with white board before each test. Each sample was tested for three times and the average number was calculated. The number of L*a*b* among two kinds of ceramic core material and veneered core material with different post-and-cores were compared using one-way ANOVA and LSD test. The number ofâ–³L*â–³a*â–³b* among two kinds of all ceramic core material and veneered core material, the two kinds of all ceramic samples on the same background were compared using paired-samples T test. Results:1.The four groups of background post-and-core influence the final color of In-Ceram Alumina core material with significant difference.2. The four groups of background post-and-core influence the final color of In-Ceram Alumina veneered core material with significant difference.3. The four groups of background post-and-core influence the final color of IPS-Empress II core material with significant difference.4. The four groups of background post-and-core influence the final color of IPS-Empress II veneered core material with significant difference.5. The differences between the L* value of each group have statistical significance. L* values decreased as the following order:opaque veneered Ni-Cr alloy, resin, glide Ni-Cr alloy and Ni-Cr alloy but there is no clear rules in the difference between a* and b* values.6. The minimum color difference of In-Ceram Alumina core materials exists on the resin. But on the background of Ni-Cr alloy post and core, the value is beyond the acceptable range. The color difference of In-Ceram Alumina core materials with opaque veneered Ni-Cr alloy and glide Ni-Cr alloy can be seen by eyes, but it is acceptable.7. The minimum color difference of IPS-Empress II core materials exists on the resin. The color difference of IPS-Empress II core materials with Ni-Cr alloy, opaque veneered Ni-Cr alloy and glide Ni-Cr alloy is beyond the acceptable range.8.The color difference of In-Ceram Alumina veneered core material with Ni-Cr alloy is beyond the acceptable range. However the color difference of other groups can not be seen by eyes.9. The minimum color difference of IPS-Empress II veneered core material exists on the resin. The color difference of IPS-Empress II core material with opaque veneered Ni-Cr alloy can be seen by eyes, but it is acceptable. The color difference of IPS-Empress II core material with Ni-Cr alloy and glide Ni-Cr alloy is beyond the acceptable range.10. The color variation between In-Ceram Alumina and IPS-Empressâ…¡is significantly different with the same kind of post-and-core. Conclusion:1. Resin has little impact on In-Ceram Alumina. The color variation of In-Ceram Alumina with opaque veneered Ni-Cr alloy and gilded Ni-Cr alloy are not visible. The Ni-Cr alloy post-and-core has much impact on the color of In-Ceram Alumina. For In-Ceram Alumina, resin post-and-core aesthetic best, glide Ni-Cr alloy and opaque veneered Ni-Cr alloy can be recommended, but Ni-Cr alloy post-and-core can not be recommended for clinic practice.2. Resin has also little impact on IPS-Empressâ…¡. The color variation of IPS-Empressâ…¡with opaque veneered Ni-Cr alloy can be seen by eyes, but it is acceptable. The Ni-Cr alloy and gilded Ni-Cr alloy post-and-core has much impact on the color of IPS-Empressâ…¡.For IPS-Empressâ…¡crown, resin post-and-core is the best choice, opaque veneered Ni-Cr alloy may be considered to use with some measures to hide the color, but glide Ni-Cr alloy and Ni-Cr alloy can not be choice.3.If adjacent teeth transparent, recommended to choose IPS-Empressâ…¡crown. If adjacent teeth less transparent, it is better to choose In-Ceram Alumina.