الفهرس 
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Abstract
One of the most challenging cases that presents to the dental office is the single, discolored central incisor. The dentist has to make the difficult decision on how to effectively and esthetically restore the tooth back to its natural color and original form. There are many different restorative techniques and materials to choose from.
Edelweiss system is a polymerized, prefabricated, laser-machined, radiopaque, highly-filled nano-hybrid composite enamel shells with a highly glossy inorganic surface. They have a facial anatomical pattern in the shape of a thin composite shell bonded to labial surface of anterior teeth with composite resin, which allows for easy direct veneering of single and multiple anterior teeth.
In this study, twenty Edelweiss veneers bonded with different shades (A2, opaque white and translucent shades) composite resin to dies of different shades (A2 shade dies and discolored dies). Specimens were divided into four groups, each group consist of five specimens, according to the shade of the bonding composite resin used and the shade of the dies. Spectrophotometer was used to evaluate the effect of using different shades of the bonding composite on the final shade of the restoration. Also, to assess the translucency, light reflection, transmission and absorption of the Edelweiss Veneer System.
The spectrophotometric measurements of each specimen were done three times: before seating the veneers on the resin dies, after seating the veneers on the resin dies and after bonding the veneers to the resin dies.
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Color change:
Seating the veneers on the resin dies without bonding composite resulted in a clinical non-significant color change for all the groups. While bonding of the veneers to the resin dies resulted in an observed color shift with the highest ΔE value related to group III where opaque bonding composite was used, followed by group IV where A2 shade bonding composite was used, then group II where translucent shade bonding composite was used.
Translucency parameter:
group I showed a non-significant change on seating the veneers on the resin dies. While, bonding the veneers to the resin dies with A2 shade composite showed significant decrease in translucency.
Seating the veneers on the discolored resin dies resulted in a significant decrease of translucency for group II,III and IV.
For group II and IV, bonding the veneers to the discolored resin dies with translucent shade and A2 shade bonding composite resulted in a non-significant change in translucency. For group III, bonding the veneers to the discolored resin dies with opaque shade composite showed significant decrease in translucency.
Light reflection and light transmission:
The highest significant value of light reflection was obtained in group III. However, the lowest significant value of light transmission was obtained in group III. Also the greatest shift of light reflection and light transmission was found in group III.
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Light absorption:
Light absorption of the specimens was not affected by the shade of the bonding composite. The values of light absorption were not significantly different between different measurements among the four groups.