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Compendium
February 2019
Volume 40, Issue 2

What Issues Must Prosthodontists Overcome to Make Digital (CAD/CAM) Dentistry a Reality in Their Practice?

Brahm A. Miller, DDS, MSc, Dipl Pros, FRCD(C); Stephen J. Chu, DMD,  MSD, CDT; David L. Guichet, DDS

Dr. Miller

Over the past decade digital technologies have propelled advanced industries such as engineering, medicine, and aeronautics at an impressive rate. The dental industry, however, has only recently begun to experience an exciting upside in the area of digital (CAD/CAM) dentistry. This technology is linking almost all aspects of what prosthodontists strive to accomplish, from thorough treatment planning to expert restoration and replacement of teeth.

Once prohibitively expensive and confined to occasional use, the digital dental platform is now readily accessible and is changing the work of prosthodontists at an astonishing pace. Even the language of dentistry has evolved, starting with the often-used term "digital workflow," which effectively describes how the digital parts all fit together and represents a digital roadmap that is constantly being upgraded as newer applications are introduced. While it may sound complex, the benefits of "going digital" far outweigh being mired in the time-tested but comparatively inadequate analog world.

Clinicians certainly may keep doing things the same way as always and continue to achieve perfectly fine results. However, many are recognizing the enormous advantages of sharing information accurately and rapidly and working seamlessly toward an end goal. Digital dentistry enables the high efficiency and accuracy that prosthodontists demand. For example, my practice uses digital technology to place patients' jaws and teeth precisely behind their lips in a 3-dimensional (3D) photorealistic image of their head and face, incorporating all the necessary reference planes and adopting this to a virtual articulator with mouth-motion capabilities. I've never been able to do this outside of using cumbersome gothic arch tracings and mechanically setting a fully adjustable articulator, which, quite frankly, not many practitioners actually do. In fact, the ease and accuracy of this technology allows me to no longer use traditional facebows and articulators.

These digital advancements can be coupled with a digitally designed smile and an accurate virtual analysis as to the need for other interventions, such as correctly diagnosing the necessity for orthodontics or oral surgery, and the ability to monitor the progress of these treatments. Implant treatment accurately planned and executed according to this imagery using printed guides can result in improved accuracy in terms of 3D implant positioning.1 An intraoral scanner provides a recording of implant emergence profiles and the final implant position; allows monitoring of recession, tooth wear, and bone/soft-tissue augmentation stability over time; and enables the planning of tooth preparations. The possibilities seem endless and are in motion at this time. The design, milling, and printing of provisional and final restorations complete the workflow, the entirety of which can be easily shared with the patient, surgeon, and technician throughout the process. Furthermore, all records are readily archived and conveniently stored in the cloud for easy access.

Perhaps the biggest obstacle prosthodontists must overcome to implement digital dentistry in their practice is having a willingness to change. While change may be inconvenient at first, it is well worth the effort. Practitioners will need to purchase an intraoral scanner and should be ready to delegate scanning to their staff. The scans will serve foremost as study models, and eventually scans of preparation margins, implant scan flags, and emergence profiles will fit in effortlessly. Prosthodontists can join virtual meetings with their technical staff to collaborate on design of final restorations or final abutments, or to simply discuss an issue such as inadequate occlusal reduction, all in a relaxed manner in front of their computer screen. Most laboratories are fully "digitalized." Prosthodontists also can team up over the computer with their off-site surgeons to visualize in 3D the anticipated final position of an implant case and address questions ahead of time.

A digital workflow can be readily incorporated into a prosthodontic practice, as long as proper initial training is received and the practitioner has a strong desire to improve patient outcomes.

Dr. Chu

New techniques and concepts in any profession require a learning curve and are frequently associated with growing pains. Whether or not clinicians believe they are part of the digital revolution, dental laboratories have largely already adopted the transition to CAD/CAM technology, and the high cost of such equipment has led to their consolidation as an industry. The issue that remains is the use of digital technology on a daily basis in the clinical arena.

Not unlike the conversion to digital radiography, the adoption of CAD/CAM has taken time. It requires financial resources and a conscious commitment from the practitioner. Also, the cost of entry into the digital CAD/CAM realm can be pricey depending on the number of treatment rooms needed and requirements of the practice with regard to scanners. Our practice has "slowed-started" the evolution with the use of an intraoral scanner and the hiring of a dental technician solely devoted to CAD. Intraoral scanning is extremely valuable for acquiring preoperative diagnostic casts, thereby establishing a patient baseline condition that can be compared over time. It is also helpful in communicating the clinical situation of the patient and the need for treatment.

Presently, in our office the intraoral scanning process is a time-consuming one that will be streamlined with increased user proficiency. Model-less restorations can be made for non-esthetic posterior full- and partial-coverage single-unit restorations. For esthetic anterior restorations, however, many technicians and clinicians still prefer models to address details such as contour and texture. Even though the input [scanning] is extremely accurate, the output [models] for full-arch restorations still has not been. As printers improve so will the precision, accuracy, and resolution of casts, and the cost of manufacturing will come down.

We have found that combining analog with digital for full-arch implant-supported restorations gives the best and most consistent results. The planning and fabrication of surgical guides for implant placement has been instrumental in converting this specialty. The employment of digital dentistry in orthodontics has been transformational with the partnering of digital planning for bracket placement and aligners.

As previously mentioned, the greatest impact of CAD/CAM has been in the dental laboratory theater where time, efficiency, and consistency of fabrication all have benefited from this technology, thereby offsetting initial startup expenses. Those who have made the commitment to digital dentistry will most likely say that the growing pains were worth it.

Dr. Guichet

For prosthodontists to invest the necessary time and money to switch from traditional techniques to CAD/CAM technology, the new digital solutions must offer real or perceived advantages, because benefits motivate change. To make digital dentistry a reality in practice, one must be able to identify, adapt, and lead.

Identify: Once a practitioner identifies a digital dentistry solution, there are many stages to managing successful integration. After installation, the new solution requires training, adoption, troubleshooting, and maintenance. Ergonomic clinical and laboratory workstations will need to be set up. Capital investments in equipment will be required to implement new technologies to solve specific problems. The office network or Wi-Fi system may need to be upgraded to match the capabilities of the latest intraoral scanner. Each investment must be rigorously justified before the practice should proceed, and considerations must be made regarding existing hardware and software capabilities. Today's solutions are well tested and within the financial means of most practices.

Digital workflows are software solutions designed to meet clinical needs. The practitioner must be able to identify and become adept at each new workflow. One workflow I initially incorporated was to design and order surgical guides. At first, this was a closed solution with a centralized printing center for the production of the guide. Now we mill or print guides in-house, but to accomplish this we had to move from closed platforms to open solutions and learn to unlock the optical scans and produce STL patient files. These were then merged with radiographic CBCT data in open software to design and print the guides. Other workflows were added as well. For implants we incorporated scan-bodies for CAD/CAM abutment and crown designs. We have incorporated 3D digital diagnostic wax-ups and milled provisionals. Most recently, we've added diagnostic workflow capabilities such as 2D and 3D smile design, orthodontic treatment simulation, and occlusal wear and gingival recession monitoring.

Adapt: Digital dentistry demands continued learning because software proficiency is required. Prosthodontists performing guided surgery may like the idea of using surgical guides but may not be proficient in all aspects of 3D CAD/CAM software workflows. Designing surgical outcomes in 3D is a learned skill and may require a considerable investment in time and education. Partnering with skilled team members may help mitigate this time investment. Also, team members need to be trained to perform portions of digital workflows. Our laboratory now performs nearly all the steps for creating surgical guides except for choosing final implant size and position.

Lead: Prosthodontists and high-end restorative dentists are well-positioned to take advantage of these newer capabilities. Using digital dentistry is like being handed the keys to a Formula 1 racecar. Engineers design the car for performance, but some drivers achieve speeds the engineers never expected. With digital dentistry, the clinician is the driver. Safe, effective, creative outcomes and customizable solutions are readily attainable, as today it is easier than ever to simulate a patient's new smile and predictably achieve it. These are drivers of change that can transform the way one practices.

About the Authors

Brahm A. Miller, DDS, MSc, Dipl Pros, FRCD(C)
Certified Specialist in Prosthodontics/Implant Dentistry, University of British Columbia, Vancouver, Canada; Private Practice, North Vancouver, British Columbia, Canada

Stephen J. Chu, DMD, MSD, CDT
Adjunct Clinical Professor, New York University College of Dentistry, New York, New York; Executive Editor,
Compendium; Private Practice, New York, New York

David L. Guichet, DDS
Private Practice specializing in Prosthodontics, Orange, California; Diplomate,  American Board of Prosthodontics

References

1. Wismeijer D, Joda T, Flügge T, et al. Group 5 ITI Consensus Report: Digital technologies. Clin Oral Implants Res. 2018;29 suppl 16:436-442.

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