Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2018-02-22, 09:57:51 | version 1.38.0
D2 ◊Page D1 Instrumentation and Workfl ow Dynamic guided navigation works on the principle of tracking two markers in their positions relative to each other. One marker rests on the patient’s jaw, and is usually teeth supported. This marker is placed on the patient’s teeth, usually on the opposite side (for example, if the implant is placed in the lower right quadrant, the marker is positioned in the lower left quadrant) using a thermoplastic resin to be able to re- produce the same position during surgery. A cone beam CT scan is tak- en with this marker in position in the patient’s mouth. The dental surgeon plans the placement of implants in a virtual treatment planning soft- ware, that is usually included in the dynamic navigation machine (Fig. 1). Since there is no need to manu- facture a physical guide, the surgery may be scheduled as early as the next day. On the day of the surgery, the second marker is fi xed to the sur- gical hand-piece according to manu- facturer recommendations (Fig. 2). The marker in the hand-piece and the marker in the patient’s mouth are calibrated in position to each other as well as to the proposed po- sition of the implants. This is done using two cameras which are part of the navigation guide system (Fig. 3). In short, a dynamic navigation guide system has the following essential parts: 1. A hand-piece attachment/ marker 2. A jaw attachment/ marker 3. Cameras and sensors to record and monitor the position of markers be- fore and during surgery, and 4. A software which co-ordinates the information received from the pre-surgical cone beam CT scan and correlates it with proposed position of the implant during the actual sur- gery and acts as a guide. The machine, which has recorded the fi nal position of the implant in all three axes from the information obtained from the cone beam CT scan as well as the virtual implant planning software, and is able to guide the surgeon’s hands with great precision in real time using motion- tracking technology. Surgery begins as soon as calibration is done. The cameras track the orien- tation and depth of the drill as the surgeon begins the osteotomy in the traditional fashion. The surgeon cor- relates the position of the osteotomy drill and subsequently the implant with real time feedback from the software. Discussion Guided implant surgery can be per- formed in two ways, Static and Dy- namic. The static approach refers to the use of a static surgical template. IMPLANT TRIBUNE Dental Tribune Middle East & Africa Edition | 5/2017 The position of the implant is repro- duced on the surgical guide from the virtual implant placement per- formed on the cone beam CT scan, and hence does not allow intra-oper- ative modifi cation of the implant po- sition9,10. With the static systems, the planned implant location is usually transferred to the surgical template by a specially designed drilling ma- chine11. Another Static option, called the Stereolithographic method, uses specifi cally designed software to de- sign the surgical stent virtually and then fabricate it using polymeriza- tion of an ultraviolet sensitive liquid resin12. The dynamic approach refers to the use of a surgical navigation system that reproduces the virtual implant position directly from com- puterized tomographic data and al- lows intra-operative changes of the implant position9,10. These systems are based on motion- tracking tech- nology that allows real-time tracking of the dental drill and the patient throughout the entire surgery13. The placement of dental implants needs to be prosthetically driven. Proper placement of the implants results in favorable esthetic and functional outcomes. A multi-center study involving 478 patients and 714 implants have shown that there are signifi cant positional and angular er- rors in freehand implant placements as compared to dynamic guided placements8. They have concluded that dynamic guiding systems are at least as accurate as static systems, and much more accurate as com- pared to freehand placement. Mul- tiple studies have asserted on the matter of high accuracy of dynamic guides14-17. Dynamic guided implant placement has many advantages over static guides. Developing a treatment plan is faster and easier, and there is no need to take an impression and rely on the guide manufacturer and wait for the guide. A signifi cant advan- tage over static guides is that there is no bulky guide that needs to be placed on the patients’ jaw. It, in turn, results in increased patient and sur- geon comfort. The absence of a phys- ical guide also helps the surgeon in visualizing the alveolar ridge during implant placement, if need be. It also allows for changes to be made in relation to size of implant, site of placement and the choice of implant system used at anytime during the surgery, unlike in a static guide. The cost of using the navigation system is less as compared to using a static guide system. A static guide sys- tem requires the use of rigid, often bulky splints which have sleeves to direct the osteotomy drills to the pre-planned position. A dynamic guided navigation system results in more consistently accurate implant placement as compared to static guides, which in turn is proven to be more accurate than freehand place- ment17-20. A signifi cant advantage of this navigation is the universal appli- cability of any implant system that can work with this technology. The present dynamic navigation systems require a few teeth to be present for the placement of the jaw marker, and hence makes it diffi cult for usage in edentulous arches. The initial high cost of the system is also a deterrent. Static guide navigated implant place- ment, on the other hand, does not al- low the fl exibility of on-site changes by the surgeon. If the surgeon feels that the position needs to be altered by even a minute degree, the guide will have to be removed during the surgery, hence defeating the very purpose of using one. Further, using a static guide renders the surgeon blind to the surgical site, who has to rely entirely on the accuracy of the splint which is manufactured off-site, in a lab. The cost of manu- facturing a splint is signifi cant, and adds to cost of treatment. The time it takes to manufacture the splint dic- tates scheduling the surgery at least a week after formulating the treat- ment plan. The surgeon still has to contend with reduced working space in the oral cavity after positioning the splint, owing to its bulky nature. Using a static guide system also ne- cessitates the use of manufacturer- specifi c guided surgery implant kits, with special drills and other instru- ments. Conclusion There is a signifi cant learning curve involved in using a dynamic guide for implant placement21. According to a few studies, as many as 25 to 125 cases may need to be done by a sin- gle surgeon in order to get comfort- able in using any new technological addition to existing practices22-23. The advent of dynamic computer navigated systems is a game chang- er, and has the potential to eliminate, or at least reduce drastically the mar- gin of error in implant placements. Implant dentistry is a relatively new aspect of Dental care, and any new technological advance needs to be assessed scientifi cally. In order to do so, more data from non-biased rand- omized controlled trials is the need of the hour. Declaration The authors do not have any per- sonal stake or interest in any of the instruments or machines described/ shown in the fi gures. No compensa- tion has been received for any of the products described in this article. References 1. Scherer U, Stoetzer M, Ruecker M, Gellrich NC, von See C. Template- guided vs. non-guided drilling in site preparation of dental implants. Clin Oral Investig. 2015;19(6):1339-46. accuracy multaneous guided bone regenera- tion following single-tooth extrac- tion in the esthetic zone: 12-month results of a prospective study with 20 consecutive patients. J Periodon- tol. 2009;80(1):152-62. 12. Buser D, Wittneben J, Bornstein MM, Grutter L, Chappuis V, Belser UC. Stability of contour augmenta- tion and esthetic outcomes of im- plant-supported single crowns in the esthetic zone: 3-year results of a prospective study with early im- plant placement postextraction. J Periodontol. 2011;82(3):342-9. 13. D’Haese J, Ackhurst J, Wismeijer D, De Bruyn H, Tahmaseb A. Current state of the art of computer-guided implant surgery. Periodontol 2000. 2017;73(1):121-33. 14. Chiu WK, Luk WK, Cheung LK. Three-dimensional of implant placement in a computer- assisted navigation system. Int J Oral Maxillofac Implants. 2006;21(3):465- 70. 15. Kramer FJ, Baethge C, Swennen G, Rosahl S. Navigated vs. conventional implant insertion for maxillary sin- gle tooth replacement. Clin Oral Im- plants Res. 2005;16(1):60-8. 16. Brief J, Edinger D, Hassfeld S, Egg- ers G. Accuracy of image-guided im- plantology. Clin Oral Implants Res. 2005;16(4):495-501. 17. Casap N, Wexler A, Persky N, Sch- neider A, Lustmann J. Navigation sur- gery for dental implants: assessment of accuracy of the image guided im- plantology system. J Oral Maxillofac Surg. 2004;62(9 Suppl 2):116-9. 18. Block MS, Emery RW, Cullum DR, Sheikh A. Implant Placement Is More Accurate Using Dynamic Navigation. J Oral Maxillofac Surg. 2017. 19. Lee JH, Park JM, Kim SM, Kim MJ, Lee JH, Kim MJ. An assessment of template-guided implant surgery in terms of accuracy and related factors. J Adv Prosthodont. 2013;5(4):440-7. Editorial note: Full list of references available from the publisher. Fig. 1: Virtual implant planning surgical 2. Noharet R, Pettersson A, Bourgeois D. Accuracy of implant placement in the posterior maxilla as related to 2 types of surgical guides: a pilot study in the human cadaver. J Prosthet Dent. 2014;112(3):526-32. 3. Zhao XZ, Xu WH, Tang ZH, Wu MJ, Zhu J, Chen S. Accuracy of computer- guided implant surgery by a CAD/ CAM and laser scanning technique. Chin J Dent Res. 2014;17(1):31-6. 4. Beretta M, Poli PP, Maiorana C. Ac- curacy of computer-aided template- guided oral implant placement: a prospective clinical study. J Peri- odontal Implant Sci. 2014;44(4):184- 93. 5. Pettersson A, Kero T, Soderberg R, Nasstrom K. Accuracy of virtually planned and CAD/CAM-guided im- plant surgery on plastic models. J Prosthet Dent. 2014;112(6):1472-8. 6. Van de Wiele G, Teughels W, Ver- cruyssen M, Coucke W, Temmerman A, Quirynen M. The accuracy of guid- ed surgery via mucosa-supported stereolithographic tem- plates in the hands of surgeons with little experience. Clin Oral Implants Res. 2015;26(12):1489-94. 7. Ozan O, Turkyilmaz I, Ersoy AE, McGlumphy EA, Rosenstiel SF. Clini- cal accuracy of 3 different types of computed tomography-derived ste- reolithographic surgical guides in implant placement. J Oral Maxillofac Surg. 2009;67(2):394-401. 8. Vercruyssen M, Cox C, Coucke W, Naert I, Jacobs R, Quirynen M. A randomized clinical trial com- paring guided implant surgery (bone- or mucosa-supported) with mental navigation or the use of a pi- lot-drill template. J Clin Periodontol. 2014;41(7):717-23. 9. Jung RE, Schneider D, Ganeles J, Wismeijer D, Zwahlen M, Ham- merle CH, et al. Computer technol- ogy applications in surgical implant dentistry: a systematic review. Int J Oral Maxillofac Implants. 2009;24 Suppl:92-109. 10. Tahmaseb A, Wismeijer D, Coucke W, Derksen W. Computer technol- ogy applications in surgical implant dentistry: a systematic review. Int J Oral Maxillofac Implants. 2014;29 Suppl:25-42. 11. Buser D, Halbritter S, Hart C, Born- stein MM, Grutter L, Chappuis V, et al. Early implant placement with si- Fig. 2: Instrumentation Fig. 3: Picture shows position of the surgeon and the dual cameras in relation to the patient Fig. 4: The jaw marker is seen fi xed on the patient’s left side. The drill is in position to begin osteotomy Fig. 5: Real time navigation as seen on the monitor Initial Consult, radiographs and study models CBCT with Jaw marker affi xed to patient’s teeth using thermoplastic resin Virtual Implant planning to decide fi nal position of implant Day of surgery- calibrate jaw marker, hand-piece marker and dual cameras with patient in fi nal position for surgery Surgeon lets the software guide orientation and depth of osteotomy and implant Flowchart