Methods for tracking orthodontic treatment progress

A method for tracking progress of a patient undergoing orthodontic treatment, the method comprising:

• providing a physical reference device for positioning proximate to a dental arch of the patient;
• generating, via one or more processors, a three-dimensional (3D) model of a dental arch of the patient while the patient is undergoing the orthodontic treatment, wherein the 3D model is generated by:
• positioning the physical reference device proximate to the dental arch,
• obtaining a plurality of images of the dental arch while the physical reference device is positioned proximate to the dental arch, wherein at least some images of the plurality of images include a portion of the dental arch together with a portion of the physical reference device,
• for each image of the at least some images including the portion of the dental arch together with the portion of the physical reference device, determining a registration location and a registration orientation between the each image and at least one other image of the at least some images using the portions of the physical reference device in the respective images to improve registration accuracy, and
• stitching the at least some images together according to the determined registrations locations and registration orientations to generate at least a portion of the 3D model of the dental arch;
• comparing, via the one or more processors, the 3D model of the dental arch to a previous 3D model representing an earlier state of the dental arch, wherein the previous 3D model is generated using the physical reference device;
• and
• outputting, via the one or more processors, data indicative of the comparison of the 3D model of the dental arch to the previous 3D model.