A computer-implemented method (100) for generating, by one or more computer processors, a 3-dimensional model (100) for use in assisted navigation in the
oral cavity of a patient, wherein the method is based on at least one initial scan of an anatomical region of the patient's
oral cavity, comprising: receiving an initial
data set comprising surface boundary information from the initial scan, and generating a 3-dimensional digital
patient model from at least a portion of the initial
data set, performing a 3-dimensional surface scan of a portion of the
oral cavity using a 3-dimensional surface
scanner and thereby acquiring a 3-dimensional surface scan, wherein the 3-dimensional surface scan comprises a
region of interest, aligning the acquired 3-dimensional surface scan with at least a portion of the 3-dimensional digital
patient model, and definingusing the acquired 3D surface scan and the digital
patient model, a
spatial transformation designed to align the acquired 3D surface scan and the 3D digital patient model or to bring them to a predetermined degree of overlap, determining position and orientation information of the 3D surface
scanner relative to a 3D digital patient model using at least the transformation, and generating a second dataset comprising the position and orientation information of the 3D surface
scanner relative to the 3D digital patient model.