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Superimpositions2D Superimpositions: Can be implemented on screen in some commercially available software such as Dolphin however, some modifications to existing software systems would insure that these systems would find use in Orthodontic departments for the purpose of training residents in cephalometric analysis and superimposition. Specifically JCEG would recommend the following features to insure that a software program would meet the needs of academic institutions’ teaching mission: 1. The ability to locate four corner Baumrind fiducials on scanned cephalograms and the ability to place fiducials permanently on digital cephalometric images. The technical specifications for fiducials will be supplied by the CRIL Team. 2. When two tracings are superimposed the relationships among the four pairs of fiducial landmarks should be preserved. 3. The ability to use a “Wacom Type” tablet to draw lines on the computer display much like using a pencil on tracing paper. In the future, touch screen technology may eliminate the need for the tablet. 4. The ability to superimpose the tracings on these lines without regard to actual landmark location. And the ability to use these free hand lines for regional as well as Cranial Base superimposition. 5. Free hand lines should be independent of landmark locations. Thus, cephalometric analysis would use landmark locations and superimpositions could use the free hand lines. JCEG would like to emphasize that traditional cephalograms generate a prospective image and current native digitally captured cephalometric images are not prospective but are orthogonal images. This means that linear measures from standards generated from traditional films may not apply. NB It is important to have machine calibration checked periodically to insure that the image is not distorted. When generating cephalograms from 3D CBCT, most systems allow both orthogonal and prospective images to be created. JCEG recommends using the orthogonal image if both images are generated from 3D data. The only reason to use the prospective image is when you want to compare a traditional (i.e. plane film not digital cephalogram) to a CBCT generated cephalometric image. And when creating a prospective image from CBCT data you need to match the source object distance and object cassette distance to match the cepholostat that was used to generate the traditional cephalogram. Because the Bolton Standards created by Bill Golden used the Bolton orientator, the standards are orthogonal to the extent that the central ray actually passed through the machine porion axis. (A reasonable assumption). Tolerances for research should approach 0.1 mm because the results of research influence clinical treatment decision making. 3D Superimpositions: To the extent possible, 3D superimposition must incorporate what is known about the biology of facial growth. At the present time open source software tools are available for superimposition but are not “user friendly”. Commercial software that is more “user friendly” may not be as accurate or give consistent results. There are still uncertainties about how to transfer what is known about accurate 2D superimposition to the 3D environment. 3D Morphologic StandardsTemplate analysis may find renewed interest in the digital environment since the limitations of size variation and saving the superimposition of the template over the image are both easily solved with digital media. Linear and angular measures are useful for quantitative studies. Registration of images is critical in 3D for comparisons between individuals within individuals through time. It is also important that this frame of reference can be saved and that the origin can be specified within the image volume and that the origin can be changed to facilitate different analyses. Surface 3D scans is the new term for next year for this working group. This term was changed to include Digital Study Casts and 3D facial scans. The technology has evolved rapidly resulting in reduced cost of hardware bringing the technology within reach of the average practitioner. CAD CAM orthodontic appliances are likely to widely used within the next three years. And, as 3D facial scans approach 300dpi resolution they are likely to replace digital photography within 5 years. Nomenclature/Terminology- This working group has been placed on hold until further notice. Image Quality and Machine Parameters- What is the role of 2D imaging in a 3D world? 2D imaging is still valuable. JCEG endorses the “Image Gently” program and supports the position paper developed jointly by AAO members and maxillofacial radiologists. Database of 3D CT images- Shelly Baumrind and the Legacy Collection. A formal demonstration of the Legacy project will be included in next years JCEG agenda.