Zeiad H. Seif-Alnasr , Yousreya A. Shalaby And Naguib El-Fawal,

ABSTRACT
Background: There Has Been Increasing Interest In The Use Of Porcelain Laminate Veneers As Esthetic Restorations Because These Combine High Aesthetic Appeal, Patient Satisfaction, And Less Invasive Tooth Preparation. However, It Should Be Noted That Minimal Tooth Preparation Means That The Thickness Of The Veneers Is Reduced, Which Leads To Increase In Translucency Leading To An Aesthetic Problem Unless The Factors Related To The Cementing Technique Are Precisely Controlled. Objective: The Aim Of This Study Was To Evaluate The Effect Of Substrate Color, Veneer Thickness And Shade Of Resin Cement On Final Shade Of Ceramic Veneers Using Digital Image Shade Matching Software.

Materials and Methods: A Metal Mold (8?8?4) Mm Was Constructed And Filled With Composite Resin Material. 60 Specimens Were Prepared 30 Specimens A2 Shade And 30 Specimens A3.5 Shade Simulating Teeth Shades. Serial Thin Slices Ceramic Specimens Were Obtained From Multilayered Glass-ceramic Blocks (IPS Empress CAD Multi C14 A1) Using A Low-speed Precision Cutter Under Water Cooling: 30 Ceramic Specimens Of (8?8?0.55 Mm); And 30 Ceramic Specimens Of (8?8?0.8 Mm). One Surface Of Each Ceramic Specimen Was Etched Using 5% Hydrofluoric Acid IPS Ceramic Etching Gel For 20 Seconds, Rinsing And Air Drying + Application Of Silane Monobond-S For 60 Seconds, And Air Drying. Opaque, White And Transparent Resin Cement Multilink? Were Used For Cementation Under Static Load 2.5kg. Shade Analysis Was Done Using Shade Wave Software And Adobe Photoshop C6 Before And After Luting Of The Veneers With Resin Cement.

Results: The Substrate Influenced The Final Color Of The Veneers Without Significant Difference Between Substrate A2 And A3.5. Increasing The Thickness From 0.5mm To 0.8mm Significantly Reduced The Value Of Delta E. Opaque Cement Resulted In Higher Delta E Than White And Transparent Cement With Significant Difference Between The Three Cements Only While Using 0.5mm Veneer Thickness.

Conclusions: It Was Concluded That Substrate, Ceramic Thickness And Shade Of Resin Cement Together Play A Detrimental Role In Changing The Final Color Of Laminate Veneers And Should Be Considered Carefully To Obtain Optimum Results.