COLOR PRODUCTION AND TRANSLUCENCY OF THREE CAD/CAM CEMENT RETAINED IMPLANT SUPPORTED CROWN MATERIALS USING TWO CEMENTS (AN IN VITRO STUDY)

Abstract

This study was designed to evaluate the effect of using three crown materials that can be used with implants in case of immediate occlusal and non-occlusal loading protocols. The material should be able to transfer less forces to the implant and to the bone surrounding to avoid possible implant failure, at the same time the material should be able to produce good esthetic properties and show harmony with the surrounding dentition regarding translucency and color production. Certain factors were mentioned in this study affecting optical properties of the restorations such as: shade of the cement, translucency of restorations and color of the background. Three implants were embedded in epoxy resin blocks A, B, C. Scanning of implant abutments was done using CAD/CAM machine. One of the abutments was left uncolored and the other two were colored black and white. Milling of crowns (n=42) using CERASMART CAD/CAM, BioHPP CAD/CAM and Vita Enamic blocks as follows: Group (I) : milling of 21 CERASMART crowns (n=14) Group (II) : milling of 21 BioHPP crowns (n=14) Group (III): milling of 21 Vita Enamiccrowns (n=14 ). All specimen had the same thickness when milled. Each group of crowns was cemented over the abutments using two different resin cements, colored temporary resin cement and translucent temporary resin cement. The color and translucency were tested using an in-lab spectrophotometer" Easyshade Advance 4.0." For measuring translucency A quantitative measurement will be obtained by measuring the CIELAB coordinates of the crown after backing with a white background with the following CIELAB (CIE L*=96.7, a*=0.1, b*=0.2) and then with a black background with the following CIELAB (CIE L*=10.4, a*=0.4, b*=0.6) using the Easy shade Advance 4.0.for each crown three measurements will be taken and their average will be recorded. the contrast ratio(CR) for each crown will be calculated according to the following equation.