1. A computing device implemented method of virtual cephalometric imaging, comprising: correlating a first 3D virtual model and a second 3D virtual model of a patient's dentition, wherein the first 3D virtual model is based on the patient's dentition at a first time and the second 3D virtual model is based on the patient's dentition at a second time; generating a 2D image including a first outline representing a position of at least one tooth of the patient's dentition according to the first 3D virtual model and a second outline representing a position of the at least one tooth according to the second 3D virtual model; and wherein generating the 2D image includes positioning the first outline relative to the second outline according to the correlation of the first and the second 3D virtual models.