An apparatus for measuring surface topography of at least part of a patient's dentition, the apparatus comprising: an optical probe configured to be moved relative to the at least part of a patient's dentition; an illumination unit (30, 34, 38) configured to generate a plurality of incident light beams, each of the incident light beams comprising a first wavelength component; an optical system configured to focus the first wavelength component of each of the plurality of incident light beams to a respective fixed focal position relative to the optical probe, wherein the optical system comprises a static focusing optics; a detector unit configured to measure a characteristic of each of a plurality of returned light beams that are generated by illuminating the at least part of a patient's dentition with the incident light beams; and a processing unit coupled with the detector unit and configured to determine surface topography of the at least part of a patient's dentition based at least in part on the measured characteristic of the plurality of returned light beams for a plurality of different relative positions and/or orientations between the optical probe and the at least part of a patient's dentition without optically moving the position of the focal positions relative to the optical probe, a motion tracking device configured to collect motion data, and wherein the processing unit comprises one or more processors and a tangible non-transitory storage device storing instructions executable by the one or more processors to cause the one or more processors to process the motion data to determine relative position and/or orientation between the optical probe and the at least part of a patient's dentition. an optical probe configured to be moved relative to the at least part of a patient's dentition; an illumination unit (30, 34, 38) configured to generate a plurality of incident light beams, each of the incident light beams comprising a first wavelength component; an optical system configured to focus the first wavelength component of each of the plurality of incident light beams to a respective fixed focal position relative to the optical probe, wherein the optical system comprises a static focusing optics; a detector unit configured to measure a characteristic of each of a plurality of returned light beams that are generated by illuminating the at least part of a patient's dentition with the incident light beams; and a processing unit coupled with the detector unit and configured to determine surface topography of the at least part of a patient's dentition based at least in part on the measured characteristic of the plurality of returned light beams for a plurality of different relative positions and/or orientations between the optical probe and the at least part of a patient's dentition without optically moving the position of the focal positions relative to the optical probe, a motion tracking device configured to collect motion data, and wherein the processing unit comprises one or more processors and a tangible non-transitory storage device storing instructions executable by the one or more processors to cause the one or more processors to process the motion data to determine relative position and/or orientation between the optical probe and the at least part of a patient's dentition.