Digital Technologies Paving the Way for Implant Dentistry’s Expansion
Gary Orentlicher, DMD
To borrow the highly popular advertising slogan from the 1970s and 1980s, implant dentistry has "come a long way, baby" over the past four decades. From the 1982 Toronto Conference on Osseointegration in Clinical Dentistry in which the evidence-based concept of osseointegration was first introduced in North America to the present, the growth and expansion of implant dentistry has revolutionized the dental industry and changed the lives of millions of patients functionally and esthetically. Since 1982, there's been no looking back.
In the past decade, dentistry has witnessed a tremendous expansion in the use of digital technologies for patient education, diagnosis, evaluation, treatment planning, surgery, and prosthodontic rehabilitation. Almost daily, new digital-based products are being introduced to the dental community with the intention of improving patient care and outcomes. Few areas in dentistry have had more product development and clinical introduction than digital imaging and surgical planning. This report will concentrate on a few key aspects of this category of implant dentistry.
Cone-Beam Computerized Tomography (CBCT)
Nothing has revolutionized the diagnosis and treatment planning of dental implants more than the introduction of CBCT by Mozzo et al in 19981 and its approval by the US Food and Drug Administration (FDA) in 2001. Although oral and maxillofacial surgeons, because of their hospital-based training, were familiar with 3-dimensional (3D) facial-skeletal evaluations (axial, coronal, and sagittal views) using computerized axial tomography (CT/CAT) scans, most dentistry, including implant dentistry, was performed using conventional 2-dimensional (2D) periapical and panoramic radiographs. CBCT moved dental radiology from 2D to 3D.
The advantages of CBCT include a rapid scan time (usually 4 to 8 seconds), reduced radiation and scatter,2 high image accuracy and resolution,3 convenience, and a small machine footprint appropriate for in-office dental/surgical office utilization. On the other hand, disadvantages comprise image graininess (secondary to lower radiation exposure),4 limited contrast resolution (from high scatter radiation during image acquisition),5 the lack of CBCT correlation to Hounsfield units and the corresponding 3D reformation image distortion when imported into proprietary dental implant planning software applications,6 and the relative high cost of the machines (although prices have greatly reduced from a decade ago).
Intraoral Optical Scanners (IOS)
The introduction and expanded use of IOSs in dentistry has taken place over the course of more than 30 years with the development of computer-aided design/computer-aided manufacturing (CAD/CAM) technologies and the launching of Chairside Economical Restoration of Esthetic Ceramics (CEREC®) in the 1980s.7 For several decades the use of IOSs was primarily by restorative dentists and prosthodontists. Over the years, the ergonomics and size of the scanners have improved and gotten smaller, the software and hardware requirements have become simpler, the number of available machines has grown, costs have dropped, and the applicability of utilizing the digital information has expanded. As a result, IOSs are now being integrated into many specialty practices as well. The ability to import standard triangulation language (STL) files, created from IOSs and model/impression scanners, into treatment planning software applications has allowed for the expanded use of these scanners in orthodontics, periodontal surgery, oral and maxillofacial surgery, and dental implantology. Most major dental implant treatment planning software applications currently can overlay STL files with the digital imaging and communication in medicine (DICOM) files created from CT/CBCT imaging. Once combined, software applications will commonly allow for the addition of "virtual" teeth and the accurate and predictable virtual placement of dental implants.
Surgical Implant Planning Software and Guided Instrumentation
Dental implant planning software applications have been developed and refined for more than two decades. Guided surgery has been shown to be a more accurate method to place dental implants8,9 while maximizing the ability to avoid anatomic structures.10,11 Most dental implant software applications are "open," allowing treatment planning and surgical guide fabrication with many different dental implant systems' implant "libraries." Some software applications are "closed," meaning that though they enable treatment planning with multiple implant systems, they only allow surgical guide fabrication for the placement of a specific manufacturer's dental implants.
All major dental implant manufacturers, and many smaller ones, have developed implant-specific instrumentation for the "guided" placement of their dental implants. Guided surgery instrumentation is available for the "fully guided" or "pilot-guided" placement of dental implants. Fully guided placement involves using guided instrumentation for the complete drilling sequence of osteotomies, followed by implant placement using implant mounts with surgical stops to assure accuracy in the final implant placement depth and angulation. Pilot-guided placement involves depth and angulation guidance only for the initial 2 mm to 2.3 mm osteotomy. Additional osteotomies and implant placement are then performed freehand, with no guidance. Most dental implant planning software applications and workflows result in the fabrication of stereolithographically produced, milled, or printed "static" surgical guides.
Techniques and workflows have been developed to use guided surgery in most clinical patient case applications, including extractions and immediate implant placement; immediate loading; single, multiple, and complete-arch patient cases; bone grafting cases; and tilted implant/hybrid restoration and zygomaticus implant treatment planning and implant placement.
In-Office Printers
Most implant planning software applications allow for the creation of surgical guide STL files, which can be used to fabricate guides through stereolithography (usually by the manufacturer), milling, or printing (commonly by dental laboratories). In-office 3D printers have been developed for clinicians to print guides. While some might debate the cost-effectiveness-including equipment cost, time, staffing, and volume necessary-of providing these services in-office, some clinicians have nonetheless chosen to do so. A recent article by Sommacal et al questions the accuracy and appropriateness of using in-office printers as opposed to manufacturer-produced surgical guides for guided surgery.12
"Static" Surgical Guides, Dynamic Navigation, and Robotic Surgery
Although guided surgery using "static" surgical guides has been well-established and well-researched for many years, dynamic navigation and, lately, robotic surgery have recently been introduced and have proponents. Clinicians should note that literature supporting guided surgery using static guides is extensive, spanning more than 15 years. While some recent literature discusses the accuracy of dynamic navigation,13 little exists regarding robotic surgery.
There are many issues clinicians may debate regarding the different technologies and equipment available for the guided placement of dental implants, including their advantages, disadvantages, technical considerations, equipment variations, costs, time commitment needed, ease of use, and supporting literature. One must not forget that, regardless of the guided surgery method chosen, guided implant placement has been shown numerous times to be more accurate and predictable than freehand dental implant placement.
Conclusion
With the introduction and progression of the science of osseointegrated dental implants, the dental community has witnessed a revolutionary change in how clinicians evaluate, plan, and treat patients. More recent digital technologies and workflows have quickly expanded the use of dental implants and improved patient outcomes. The coming decades will undoubtedly be equally groundbreaking.
References
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3. Kobayashi K, Shimoda S, Nakagawa Y, Yamamoto A. Accuracy in measurement of distance using limited cone-beam computerized tomography. Int J Oral Maxillofac Implants. 2004;19(2):228-231.
4. Kwong JC, Palomo JM, Landers MA, et al. Image quality produced by different cone-beam computed tomography settings. Am J Orthod Dentofacial Orthop. 2008;133(2):317-327.
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12. Sommacal B, Savic M, Filippi A, et al. Evaluation of two 3D printers for guided implant surgery. Int J Oral Maxillofac Implants. 2018;33(4):743-746.
13. Block MS, Emery RW, Cullum DR, Sheikh A. Implant placement is more accurate using dynamic navigation. J Oral Maxillofac Surg. 2017;75
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