الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 100 |  |  |
| | | from | 100 | | |
Abstract
This study was designed to evaluate the effect of the previsualization technique using visual eyes modeling liquid on the color, translucency and biaxial flexure strength of three different types of veneering porcelain which are: porcelain fused to metal, porcelain fused to lithium disilicate and feldspathic porcelain.
Matching a porcelain restoration is a difficult task for both the dentist and the dental technician. Shade communication and shade reproduction for a single anterior restoration is critical; because it is usually a mix of several shades and different degrees of translucencies. Since there is a difference between the index of refraction of the porcelain powder and water, judging the final porcelain color is impossible.
A recent invention (visual eyes) introduced a new liquid binder that match the refractive index of porcelain allowing the previsualization of the presintered porcelain shade.
The specimens were prepared into discs of 15mm diameter and 1.5 mm thickness. Forty two samples were tested for the IPS e.max veneered discs, feldspathic discs and the porcelain fused to metal discs. Twenty one were prepared with the manufacture liquid, while the other twenty one were prepared with visual eyes modeling liquid. The porcelain powder was prepared for the visual eyes liquid by removing the food dyes with a firing cycle recommended by the manufacture. The porcelain mixes were added using standardized Teflon molds of different thickness. The color and translucency were tested using an in lab spectrophotometer and the biaxial flexure strength were measured with a universal testing machine.
68
Summary
The results revealed statistical significance in the translucency measurement between the manufacture liquid samples and the visual eyes samples in different types of porcelain. The manufacturer’s liquid showed statistically higher translucency than visual eye liquid, while the color difference and the biaxial flexure strength were similar between the two liquids. The color change (ΔE) in relation to shade A3 showed statistically significant highest mean ΔE for PFM followed by e.max. Feldspathic porcelain showed the lowest mean ΔE.
The difference in translucency between the liquids could be related to the minimal difference of the refractive index between the different porcelain powders and the visual eyes. Another reason could be related to the difference in the substrate used, while the color change may be due to batch variation and different opacities of the core materials.
This concludes that the use of the visual eyes liquid is indicated in specific cases of complicated buildups.
Further investigations should be done on the effect of the visual eyes modeling liquid on other properties of veneering porcelain.