IMPECCABLE IMPLANTS:The use of computer-aided design/computer-aided manufacturing, cone beamcomputed tomography, and surgical guides to create more accurate and suc- cessful implants. Mary White and Morgan Card April 14, 2011 Central Piedmont Community College Dental Hygiene Program
For years, dentists and lab technicians have placed dental implants and fabri-cated crowns and bridges. Traditionally, the process of fabrication involves diag-nostic casts, impressions and clinical records (Patel, 2010). These methods in-volve “multiple patient appointments and separate laboratory procedures involv-ing the clinician and the laboratory technician” before an implant may be placed(Patel, 2010, p.21S ). In an effort to make this process more accurate and timeefficient, two technologies have now been combined to produce a more accurate,safe, and successful implant: dental computer aided design/computer-aidedmanufacturing (CAD/CAM) and cone beam computed tomography (CBCT).In 1985, the first chairside CAD/CAM system was put into use (Poticny and Klim,2010). This system offers “dentists the opportunity to design, mill and place ce-ramic or porcelain restorations in a single appointment” (Patel, 2010, p. 20S).Since 1985, approximately 20 million restorations have been produced usingthese chairside units and according to the results of a 2001 literature review,“restorations made with CAM/CAM performed better than any other restorativematerial and equivalent to cast gold for restorations of the same type” (Poticnyand Klim, 2010, p. 5S). Other benefits of this technology include: “higher andmore uniform quality material by using commercially formed blocks of material,standardize restoration-shaping processes and reduction in production cost”(Strub, Rekow & Witkowski, 2006, p. 1290). A CAD/CAM restoration creates “op-
timal function, esthetics and biomechanics” (Patel, 2010, p. 21S).The second technology used in guided implant placement is CBCT. Introduced tothe U.S market in 2001, CBCT allows the clinician to “evaluate subjacent anat-omy, test the feasibility of the proposed implant placement and make neededmodifications to the plan to optimize the spatial and functional relationships be-tween the planned prosthetic treatment and the anatomy” (Worthington, Ruben-stein, & Hatcher, 2010, p.20S). According to Worthington, Rubenstein andHatcher (2010), the following may be seen using the 3-D tomography: thicknessof the soft and hard tissues, height, weight and quality of the bone, inner archspace, occlusion and the temporomandibular joint. Using this information, a clini-cian may avoid mental nerve damage, perforation of the maxillary sinus, and un-intended lingual perforation of the mandible (leading to possible hematoma ordamage to the sublingual gland) (Worthington, Rubenstein, & Hatcher, 2010).Also, these images are never distorted or magnified because the software corre-lates one to one, ensuring accuracy in the designing and manufacturing of a sur-gical guide (Patel, 2010).In a clinical setting, integration of CAD/CAM and CBCT for the use of a dentalimplant would be used as follows. At the first appointment, the dentist would coatthe teeth with powdery optical reflective medium and take digital impressions ofthe edentulous area in which the implant is needed, the opposing arch, and theocclusion using a “buccle bite technique”. Then a stock scanning bite plate is
seated in the patientʼs mouth with bite registration material and possibly trimmedto better fit the patientʼs mouth. The stock scanning bite plate contains small ra-diopaque markers that allow the CBCT to attain an image. Then the 3-D conebeam image is taken revealing the patientʼs surrounding hard and soft tissue andsurface anatomy. The dentist can then virtually plan the placement, shape, andtype of implant body, abutment, and crown. The dentist may assess the quality ofthe bone and the placement of anatomical structures at this point. Next, the vir-tual implant plan and the stock bite plate are shipped to a manufacturer whomakes the stock bite plate into a surgical guide according to the dentistʼs specifi-cations. At the second appointment, the implant and abutment are placed. Thecrown is milled in the office using the chairside CAD/CAM technology and maybe placed the same day. This process not only saves time, but is highly accurateand safer for the patient (Patel, 2010). According to Worthington, Rubenstein andHatcher, “Implant planning, surgical fabrication and implant placement have beentested to an accuracy of 0.9 millimeters at the ridge crest and 1.0 mm at the apexof an in vitro model,” using this type of system (Worthington, Rubenstein &Hatcher, 2010, p.22S).According to Howerton and Mora (2008), the future of these technologies will be-come more widely used throughout different fields of dentistry. They say, “con-sider a patient with a congenital deformity in the oral and maxillofacial region,malocclusion and missing teeth”, using this technology, “the oral surgeon, ortho-
dontist, implantologist and restorative dentist can link their communication suchthat pretreatment expectations equal posttreatment results.” (Howerton & Mora,2008, p. 23S-24S) They believe the future of the CBCT technology depends onan increase of imaging centers and more trained oral and maxillofacial radiolo-gists (Howerton & Mora, 2008). Strub, Rekow and Witkowski (2006) also agreethat the expansion of these technologies may change dramatically, but it will relyon the specialized training of dental professionals in order to use them to their fullcapacity. As of now, these technologies are substantially beneficial to both pa-tients and dental professionals. Implant placement is and will likely become safer,more timely and overall more successful with the combined use of CAD/CAM,CBCT, and surgical guides.
Work CitedHatcher, D.C. (2010). Operational Principles for Cone-Beam Computed Tomo graphy. The Journal of the American Dental Association, 141, 3S-6S.Howerton, W.B. Jr., & Mora, M.A. (2008). Advancements in Digital Imaging: What is New and on the Horizon?. The Journal of the American Dental Associa tion, 139, 20S-24S.Patel, N. (2010). Integrating Three-Dimensional Digital Technologies for Com prehensive Implant Dentistry. The Journal of the American Dental Associa tion, 141, 20S-24S.Poticny, D.J., & Klim, J. (2010). CAD/CAM In-office Technology: Innovations Af ter 25 years for Predictable, Esthetic Outcomes. The Journal of the Ameri can Dental Association, 141, 5S-9S.Strub, J.R., Rekow, E.D., & Witkowski, S. (2006). Computer-aided design and fabrication of dental restorations: Current systems and future possibilities. The Journal of the American Dental Association, 137, 1289-1296.Worthington, P., Rubenstein, J., & Hatcher, D.C. (2010). The Role of Cone-Beam Computed Tomography in the Planning and Placement of Implants. The Journal of the American Dental Association, 141, 19S-24S.