ortho - the international C.E. magazine of orthodontics

ortho1_2012 I 07 Fig. 4_The 3-D CBCT showing anatomy of the maxillary sinuses. Fig. 5_Axial MPR showing mesial buccal roots in first, second and third molars. C.E. article_ application of 3-D imaging I images can be viewed as conventional radiographs, maximum intensity projections (MIP), soft-tissue projections and a variety other views. This nearly endless ability to manipulate the data aids in the diagnosis and identification of disease, nerve canals, sinus morphology, dental caries, bone density, fractures, endodontic pathology, implant placement criteria, periodontal defects, bone pa- thology, fractured teeth, iatrogenic trauma, TMJ morphology and disease, third-molar position and many more healthy or diseased conditions. _Early CBCT adoption with implants ThefirstandprimaryuseofCBCTforearlyadopters was implant placement. As the scope and the value of the information became better known, dentists of all branches began to see the value of MPRs and 3-D renderings including periodontics, endodontics, oral surgery, treatment of TMJ, orthodontics, implantol- ogy and general dentistry.1,7,8 Clinicalperiapicalandpanoramicradiographsfor the placement of implants can be misleading with elongation, foreshortening, superimposition and geometrically incorrect data.7,8 A look at the implant intheperiapicalshowsnoobviousdiseasetoanexist- ingintegratedimplant.Clinically,abuccalfistulawas present with exudate and slight pain. The CBCT scan (Fig. 1) reveals a more accurate view showing a buc- cal defect on a saggital MPR. A surgical flap revealed a dehiscence of the coating of the implant. Removal oftheforeignbodyresultedinanasymptomaticand healthy patient Theevaluationoftheavailablebonefortheinitial implant placement can be crucial for the long-term success of the case. If there is inadequate bone available, grafting may be a necessity. CBCT studies render the most accurate information available at a low radiation dose. The periapical shows an obvious lack of bone height, but does not show the buccal- lingual dimensions or an accurate view of the sinus morphology (Fig. 2). The MPR view of the CBCT shows all necessary measurements to perform the sinus lift and grafting withtheimmediateplacementoftheimplantfixture (Fig. 3). Three-dimensional views show the floor of thesinusandanysoft-tissuepathology(Fig.4).Hav- ing accurate measurements in all dimensions is an advantage of CBCT scanning. _CBCT and endodontics Endodontics is a field that is rapidly adopting the use of CBCT and for good reason. The inherent geometric deficiencies of 2-D radiographs make the CBCT scan a valuable adjunct to investigate the root morphology in both 3-D and MPR. The typical periapical will show superimposed canals in the anteriors, bicuspids and molars as well as unwanted bonedensitiesbothbuccalandlingualtotheaffected tooth, making the image quality poor. The ability to view MPR slices in cross-section, long axis and oblique directions gives the ability to follow all canals in any direction and show their relationship and measurements from other known structures. This virtual tour of the root morphology is a great benefit to the final treatment outcome (Fig. 5).3,4 Fig. 4 Fig. 5