AB vertical control. In all likelihood, however, it is only a matter of time before in-office 3D printing technology catches up. COMPLICATIONS Most of the studies focusing on survival of implants placed using traditional or guided methods have not found great dif- ferences in the ultimate complication: implant failure.3,4,11,12 The majority of these FIGURES 4A and 4B. Three-dimensional-image-guided surgery with vertical control of drilling (A) and implant placement (B). the criteria for inclusion. The survival rates and accuracies reported were similar to earlier studies. Behneke et al10 studied factors that affected transfer accuracy and found that flapped or flapless surgery did not sig- nificantly influence accuracy. Improved accuracy was noted, however, when the implant was placed fully guided (i.e., all drill steps and implant placement occur through the guide), as compared to freehand place- ment of the implant, with all drilling done guided, and when the final drill sequence was freehand and only the first drill(s) guided. These stud- ies illustrate additional variables that, as of yet, are not well documented in the literature: namely, whether the guide was used for the initial (pilot) drill or subsequent drills, and if the implant was placed through the guide with a vertical stop or by freehand. Further studies are needed to fully understand the impact of these variables. IN-OFFICE GUIDE PRINTING The increasing quality and availability of personal 3D printers makes in- office printing an attractive alternative to buying guides from laboratories (Figure 5). A possible downside with 3D printing technology is that, at present, these are resin-only guides. By comparison, other guides may contain metal sleeves (Figures 3A and 3B, and Figures 4A and 4B) that allow greater stability for drill guidance, for all drilling to occur through the guide, and the possibility of placing implants through the guide with FIGURE 5. Advanced technology allows in-office printing of implant surgical guides. researchers reviewed 26 patients receiving 114 implants with 3D imaging guides and found the 1-year survival of the studies were retrospective in design. How- ever, in a prospective mono-center study,13 implants was 88.6%; when looking at smokers and nonsmokers, the survival rates were 69.2% and 98.7%, respectively. They concluded that smoking might be considered a contraindication to guided implant sur- gery. In this study, some of the implants were placed in edentulous or THE USE OF NAVIGATION IS AN EMERGINGAPPROACH TO IMPLANT PLACEMENT partially edentulous patients, and all of the implants were placed flap- less. Some of the implants were immediately loaded, and these had a higher failure rate than devices that were not loaded immediately. Other studies,4,5 however, have not reported similar failure rates — neither with immediate loading, nor in heavy smokers. Further research is needed to explain these variations. ROBOTIC SURGERY The use of navigation is an emerging approach to implant placement. Also called robotic surgery, this involves the use of tracking devices attached to the patient and implant handpiece. These two positions in space are relayed to a central processing unit and superimposed on a monitor. Their relation to the previously planned implant osteotomy is displayed, and the implant handpiece can be adjusted by following the onscreen graphics. This elimi- nates the need for a surgical template, as traditionally used in image-guided surgery, and allows real-time correction during the drilling and insertion of the implant. While this technology is new and there is little information about its accuracy, the potential is massive. WHEN TO USE IMAGE-GUIDED SURGERY When the patient and implant site are straightforward — such as an upper second premolar site in a low-smile-line patient who has plenty of bone and attached gingiva — using an image-guided approach for a single implant does not offer a high return on investment. Image-guided surgery makes sense when there are challenges, such as anatomical limitations or if multiple implants are being placed in the same jaw. Using 14 Decisions IN DENTISTRY • December 2017 DecisionsInDentistry.com FIGURE 5 COURTESY IVAN CHICCHON, DDS
