Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 1 1 2004 03 15 27 32 Ghavam M Goodarzy A 2015 10 03 Statement of Problem: Esthetic materials undergo some physical and mechanical changes, during their service in oral cavity. Purpose: The aim of this study was the evaluation of the color and opacity stability of Ideal Makoo (IDM) composites and compare it with Tetric ceram. Material and methods: Fifteen disk shaped samples of each material was divided into three groups of five. Different aging treatments were applied to each group. The contrast ratio of 1mm thickness and E of the samples were evaluated at base line and after aging, using CIE system and Data Flash spectrophotometer. All the samples were kept at 37C. Results: Baseline opacity of IDM was relatively high (77.60%8.6). Both materials showed increased opacity after aging. The highest E belonged to IDM samples of B group, which was significantly more than Tetric Ceram (P https://fid.tums.ac.ir/index.php/fid/article/view/4 https://fid.tums.ac.ir/index.php/fid/article/download/4/4