An extra-oral imaging apparatus can obtain a 3D volume image of a portion of a head of a patient. Exemplary dental apparatus and/or method embodiments can provide 3D mesh models of surfaces of the maxillary dental arch and the mandibular dental arch in a 3D volume image obtained from a single extraoral scan of physical casts of the maxillary dental arch and the mandibular dental arch in an occlusal relationship. In one exemplary embodiment, a first 3D mesh model of surfaces of the maxillary dental arch model and a second 3D mesh model of surfaces of the mandibular dental arch model are generated. Then, contact areas where the first 3D mesh model and the second 3D mesh model intersect are removed to separate the first and second mesh models. In another exemplary embodiment, the first 3D mesh model and the second 3D mesh model can be aligned.
