An exemplary optical apparatus has an OCT imaging apparatus with a first light source for low coherence light of wavelengths above a threshold wavelength and a signal detector that obtains an interference signal between low coherence light from the sample and low coherence light reflected from a reference. A surface contour imaging apparatus has a second light source that emits one or more wavelengths of surface illumination below the threshold wavelength, a camera to acquire images from illumination reflected from the sample. The exemplary optical apparatus and/or exemplary methods for using the same can provide reduced errors in generating a dental 3D surface mesh.