A method for automatic, or semi-automatic, planning of dental treatment for a patient comprises: (a) obtaining data about an area which is to be treated and data about a face of a patient； (b) performing a computer-assisted analysis of the data to determine properties of at least the face of the patient； (c) creating a modified tooth set-up using a set of stored rules which make use of the determined facial properties. A three-dimensional representation simulates the appearance of the modified tooth set-up and the patient's face surrounding the treatment area. The method also determines properties of existing teeth and creates a modified tooth set-up which is also based on the existing teeth of the patient. The method can be implemented as software running on a workstation.
