The invention is directed to an apparatus (20) for determining surface topology of a teeth portion (26), comprising a probing member (90) with a sensing face an illumination unit (28, 32, 34, 38) for providing an array of incident light beams transmitted towards the teeth portion (26) along an optical path through said probing unit (90) to generate illuminated spots on said portion a light focusing optics (42, 44) defining one or more focal planes forward said probing face at a position changeable by said optics, each light beam having its focus on one of said one or more focal plane a translation mechanism (70, 72) coupled to said focusing optics for displacing said focal plane relative to the teeth segment (26) along an axis (Z) defined by the propagation of the incident light beams (48) a detector (60) having an array of sensing elements (68) for measuring intensity of each of a plurality of light beams returning from said spots propagating through an optical path opposite to that of the incident light beams a processor (24) coupled to said detector (60) for determining for each light beam a spot-specific position, being the position of the respective focal plane of said one or more focal planes yielding maximum measured intensity of the returned light beam, and based on the determined spot-specific positions, generating data representative of the topology of said portion (26).
