cone beam international magazine of cone beam dentistry

32 I I technique _ neuromuscular application similar CBCT technology but in a sit-down and re- latively affordable system (Fig. 4). In 2008, NewTom introduced the upright VG sys- tem (Fig. 5) utilizing its exclusive Smart Beam Tech- nologywithsignificantreductioninradiationdosage.1 Withasingle10–20secondCBCTscanandalarge FOV(fieldofview),wenowhavethefull3-Dvolume of the head and neck from Nasion down to C4 including a panoramic, TMJ’s, pharyngeal airway, paranasal and maxillary sinuses, etc., with a single scan. Three-dimensional rendering and the MIP (maximum intensity projection) in Figure 6 will undoubtedly demand new cephalometric land- marksandanalyses(Fig.7)inadditiontoenhancing patient understanding and acceptance. Three-dimensional data will continue to en- hance our existing knowledge with: 1) A measureable assessment of bone quality and density (Hounsfield units). 2) The ability to measure arch widths before and after treatment (Fig. 8). 3) Actual impacted dentition orientation in three dimensions (Fig. 9). 4) Upper airway evaluation (Fig. 10). 5) Pharyngeal volumetric airway evaluation before and after treatment (Fig. 11). 6) TMJ morphology and condylar position (Fig. 12). Yet, with this technology comes the personal responsibility to further one’s education on 3-D anatomy—an absolute necessity for a proper, com- prehensive neuromuscular diagnosis. We must also learnhowtoaccuratelycreatethenecessaryimages from this single scan. Forexamplewith3-Dpans,wemustincreasethe reconstructed cut-plane width to incorporate the coronoid processes to assess potential hyperplasia andimpingementandtoincorporatemaxillarybone as well as basal bone for potential ossifications of the stylohyoid ligament (Eagles syndrome). Failure to do so will result in a myriad of false negatives and potential misdiagnoses. Proper mapping of the anatomy is no more critical than for the temporal mandibular joints, best illustrated in the below axial views. The three axial images (Submental view) in Figures 13–15 are actually on the same patient, but demonstrate three different and distinct condylar morphologies. Which one would you map for your TMJ study? The answer is Figure 13. Figure 13 demonstrates bilateral kidney shaped condyles, while both Figures 14 and 15 are indica- tive of potential osteogenic degeneration. Too often, Figure 14 is mapped with the straight TMJ tool (Fig. 16), creating the false positive of bi- Figs. 13–17_See text on page 35 for complete explanation. cone beam2_2014 Fig. 16 Fig. 14 Fig. 15Fig. 13 Fig. 17