Objectives: This study aims at establishing the average three-dimensional(3-D)morphological models of enamel dentinal junction(EDJ)of natural human premolars from extracted teeth by means of combining Cone-beam CT scanning,image processing and Spherical Harmonic Description Registration with Iterative Closest Point(SHREC algorithm)in order to provide standard mathematical model for fabrication of opticalcolor-graded esthetic dental zirconia ceramic blocks for crowns.