A computer-based prosthodontic method is provided, for enabling a dental practitioner to define a finish line of a dental prosthesis of at least one tooth to be fitted over a tooth preparation. The method comprises the following steps: providing a three-dimensional (3D) digital data relating to the patients dentition, the 3D data includes data representative of the surface topology of the preparation and its surroundings generating first finish line data representative of at least a portion of the finish line and superimposing an image of the finish line on an image of the dentition obtaining second finish line data determined on the basis of input received from a dental practitioner and using the second finish line data to update the first finish line data and superimposing the updated data on the dentition image.
