| The invention is directed to an apparatus (20) for determining surface topography of a patient's teeth (26), the apparatus comprising: a probe (46) sized to be at least partially inserted into an intraoral cavity of the patient; an illumination unit (28) configured to output light; a light focusing assembly (42, 200, 220, 230) comprising an image space lens (202), an object space lens (204) and a focus changing assembly (222, 232) between the image space lens and the object space lens and being configured to: overlap a plurality of light beams of the light within the light focusing assembly; and focus the light to a plurality of external focal planes (206) to illuminate the patient's teeth; a detector (68) configured to measure one or more characteristics of incident light returning from the illuminated patient's teeth; and a processor (24) coupled to the detector and configured to generate data representative of a topography of the patient's teeth based on the one or more measured characteristics of the incident light returning from the illuminated patient's teeth. |
