PURPOSE: To achieve determination and confirmation of a dentition of lost teeth by displaying an expected shape and an expected color tone by a TV or printing before the making of a prosthetic tooth in reference to the shape and color tone of a tooth corresponding to the lost teeth or a sample based on an image taken with a still video camera or a CCD camera.

CONSTITUTION: In the prosthesis of a lost tooth in an upper jaw front dentition, an image of the dentition 1 obtained using a still video camera or a CCD camera 3 is inputted into an image processor 4 to be stored. At this point, the image processor 4 performs a digital analysis of color tones of teeth except for the lost tooth 2 in the image simultaneously and the results are stored. A digital analysis of the color tones is performed for the materials of an artificial ceramic material which is used for the making of a prosthetic tooth and the results are collated with a color tone table 8 stored to compute and store a mixing ratio of the artificial ceramic material for the prosthetic tooth for obtaining the color tone of a retaining tooth. Based on the mixing ratio, an expected reconstruction shape and the state of the color tone are composed together with the shape stored and displayed with a TV 9 or a printer 10.