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22 I I case report _ CT-guided implant surgery guideismadefromawax-uponastonemodelthatdoes not allow representation of the true bony anatomy of the underlying edentulous ridge nor the position of adjacenttoothroots.Therearevariousstylesofsurgical guidesthathavebeeninuse,rangingfromthermoplas- ticsheetstosolidacrylicreplicasofthefinalprosthesis. These guides only estimate the position for the initial drill, leaving this up to the discretion of the surgeon, and do not control the depth of drilling. Sequential osteotomies are then generally drilled free hand. This introduces many opportunities for aberrant implant positioning.Eveninthehandsofthemostexperienced implant surgeons, up to 20 % of implant placements vary from their intended position. Dentists need only lookintheirfavouriteimplanttextbookorjournaltofind examples of textbook cases that are less than perfect. And,Ihavenevermetarestorativedentistwhohasnot hadhisorhershareofsimilarexperiences. Often, these restorative challenges can be man- aged with custom abutments and other prosthetic tricks, which significantly increase the dentist’s lab- oratory bill and affect the profitability of the case. However, in some cases, the only solution is either to not restore the fixture or to remove it and start over. Anatomical variations also pose challenges, such as a high lingual mylohyoid concavity, a surprise pneu- matisedsinus,oradivergentrootthatcamealittletoo close to the implant fixture. We do not like to have to deal with these complications, but even the best of us havefacedthemmorethanweliketoadmit. Many of my surgical colleagues are of the opinion that CT-guided surgery is unnecessary because they have been placing implants for many years using the technique they learned 15 or more years ago. I com- pletedmysurgicaltrainingin1990,andhavedonemore implants than I can count since then. And for the most part,Ihaveaveryhighsuccessrate,withminimalprob- lemcasesofwhichtospeak.But,amIperfect?Ofcourse not. Are my colleagues any better? I don’t think so. I strongly believe that CT-guided techniques will be- comethestandardofcareforimplantologywithinthe next ten years, or sooner. Those clinicians reading this article have already demonstrated an understanding of what new technologies can do for the practice of dentistry. I’m sure that few of you who own dental CAD/CAM systems could imagine practising without them and the benefits that this technology gives to your patients and your practice. The same holds true forCBCTandguidedimplantsurgery. In September 2009, I was honoured to be the sur- geonfortheintroductionandfirstlivedemonstration of the integration of GALILEOS CBCT data with that from a CEREC digital impression and prosthetic pro- posal. CEREC uses surface-scanning technology to captureadigitalimpressionofthehardandsofttissues around an area where a dental implant is being con- sidered.GALILEOSusesaradiographicsourceandsen- sor to image the bony anatomy in the area of interest. The multiple views are then processed by a computer tocreatea3-Dimageoftheteethandbone,whichcan beviewedinaninfinitenumberofcross-sectionalcuts. Both types of images are nothing more than a set of digitaldatatranslatedintoanimagethatcanbeviewed on a monitor. Merging these two sets of numbers appears to be a simple process. However, I am not a software engineer; I am just a dentist. Luckily for us, Fig. 8_Post-implant cross-sectional CBCT image demonstrating good position and angulation in relationship to provisional prosthesis. Fig. 9_Tangential slice CBCT showing implant and provisional restoration immediately after placement. Fig. 10_Clinical photograph of provisional restoration at three months after surgery. Fig. 11_Panoramic CBCT reconstruction of a 62-year-old male patient missing multiple teeth in the maxilla. Bilateral sinus-lift procedures had been performed six months prior. CAD/CAM 1_2010 Fig. 10 Fig. 11 Fig. 8 Fig. 9