Sayed A. Karim, Olfat Elsayed Hassanien and Asmaa Yassen
A total number of 44 sound non-cavitated freshly extracted upper human premolar teeth were selected for this study. Teeth were randomly divided into two main groups according to the die material. Each group was subdivided according to the storage period, after 24 hours and after 3 months with 11 teeth in each. Two Way ANOVA used to compare between tested die materials and the time intervals for mean microleakage (mm) and dimensional changes (%).One-Way ANOVA used to for interaction between variables followed by Tukey’s post hoc test for pairwise comparison. Cavity preparation: A specimen was prepared according to the principles of indirect composite restoration preparation. Specimens were centralized and fixed in the CNC machine whereby the cavity walls diverged 8-10˚ over mesial and distal surfaces were
