3D imaging has been widely used within various fields of dentistry to aid diagnosis, in treatment planning and appliance construction. Whereas traditionally this has involved the use of impression materials together with plaster or stone models, modern techniques are continually evolving which use virtual 3D images. These electronic virtual images are created using either contact or non-contact optical scanning techniques, but there are limitations, the most important of which is that any new virtual surface image is created from a series of discrete data points. It is not created from a continuous stream of data relating to the original object. This means that computer software has to be used to recreate a possible best fit, virtual surface from the data obtained. This paper describes the principles behind 3D scanning technology, the limitations of 3D imaging as well as current and possible uses of such imaging in clinical dentistry.