1. An image processing method comprising: (a) applying at least a first imaging technique and a second imaging technique to acquire a first, two-dimensional image of at least a first portion of teeth and a second three-dimensional virtual image of at least a second portion of the teeth, respectively, there being at least a partial overlap between said first and second portions; and (b) defining a set of basic landmarks in either one of the two images, locating said set in the other of the two images and registering said set in the two images.