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ortho - the international C.E. magazine of orthodontics

ortho1_201206 I I C.E. article_ application of 3-D imaging This article qualifies for C.E. credit. To take the C.E. quiz, please log on to www.dtstudyclub.com.Thequiz willbeavailableonMay1. _c.e. credit article _For nearly 100 years, dentists have relied on 2-D radiographic imaging for diagnosis and treatment planning. With the 1999 introduction of cone-beam computedtomography(CBCT),alldentistsnowhave toolsavailableformoreaccuratediagnosisandtreat- ment.1 The ability to look at a tooth in any direction and orientation, as well as in 3-D, eliminates much of the guesswork commonly experienced with 2-D radiographs. We have been limited in most cases to only a buccal-lingual view provided by periapicals, bite- wings and panoramic radiographs with the oc- casional axial view of an occlusal film. Medical CT scans and images began in the early 1970s and were sometimes used by dentists, offering our first multi- planer views.2 Theadoptionof3-Dcone-beamimagingisappro- priate and has important advantages for all modali- ties of dentistry. From every specialist to the general dentist, the increased amount of radiographic infor- mation as well as increased accuracy will aid in the most sound diagnosis possible. _CBCT description CBCT is a single or partial rotation of an X-ray sourcearoundthehead,capturingX-raysonvarious flatpanelarraysandsensors.Theinformationiscon- verted to a series of axial slices by computed tomog- raphyandstoredasvirtualanatomyinthecomputer. With the use of sophisticated software, the dentist is able to view information in several dif- ferent views, including: axial slices (head-to-toe orientation), coronal slices (front-to-back orienta- tion), saggital slices (side-to-side orientation) all known as multiplaner reconstructions (MPR). The thickness of each slice can be varied to include more or less information. Because the voxels (volumetric pixels 3-D) are isotropic, other MPR images can be generated by slicesdrawnatanyangle,curveorthicknessthrough thescantoviewareascriticaltothefinaldiagnosis.3,8 The final view offered by CBCT is a 3-D view that can be rotated and viewed in any direction. Once again through software manipulation, 3-D Author_Dan McEowen, DDS Clinical and diagnostic advantages of 3-D imaging systems in dental specialties Fig. 1_Saggital CBCT MPR showing bone defect at point of dehiscence of the implant coating. (Photos/Provided by Dr. McEowen) Fig. 2_Periapical does not show the sinus anatomy or the width of the bone. Fig. 3_MPR showing post-op of sinus graft and implant placement. Fig. 1 Fig. 2 Fig. 3