February 2010, Volume 6, Issue 2
Published by AEGIS Communications
Question: Will digital impressions become a standard of care?
Richard Simonsen, DDS, MS ; Pinhas Adar, MDT, CDT ; Paul Feuerstein, DMD ; Gregg A. Helvey, DDS
Will, or when? The short answer to “will” is of course (in my opinion) a resounding “yes!” But the real question in my mind is “when?”
Digital impressions offer many advantages, more obvious perhaps for the patient initially, but benefits for the dentist and the technician are also highly significant. The technology is here, as can be seen from the ever-expanding array of commercial products available. The cost and the acceptance time needed for the ongoing developing technology will, however, hold back the full adoption of the technology for many practitioners for some time to come.
We have, of course, had digital impressioning with CAD/CAM systems for years. Although pioneering versions are here, what remains to be refined and accepted by the profession is the full-arch impression. The digital full-arch impression would eliminate many steps in making impressions, such as tray selection, dispensing and set up of materials, and disinfection and shipping of impressions that are subject to distortion. Such technology would eliminate patient gagging during impression taking. Digital files would allow for rapid communication with the laboratory, and a record that does not distort or deteriorate with time. “Re-pouring” the impression can be done with equal accuracy to the original. Initial data suggest that remake rates will plunge with digital technology—something that all stakeholders—clinicians, laboratory technicians, and patients—will welcome.
It is, of course, folly to try to predict when the life span of a material or a technique will gain full acceptance, or run its course. While patients and dentists alike will welcome the digitization of the impressioning step, the old ways from compound or rubber base to polyvinyl siloxane will only die out slowly (just look at dental amalgam). It is the younger, more flexible, and adaptive early-adopters who will be enamored by, and who will work to overcome, the early problems with digital impression taking, which will become the standard of care.
I strongly believe that this will be the standard of care because it will simplify the experience for both the dentist and their patients, as well as also prevent common distortions that appear in impressions that are not recognizable until the laboratory pours the model. It also provides for the dentist to evaluate the tooth preparation on the computer screen and alter if necessary before taking the digital impression. It allows for the laboratory to confirm the preparation and finish line before the model is fabricated and the restoration is continued.So this technology provides value to all involved on many levels. As with many things in life, technology evolves, becomes smaller, better, and more affordable to the masses. The American Academy of Cosmetic Dentistry has recognized the importance of digital impressions and advancing technologies and, due to this recognition, has implemented “Digital World” into the exhibit hall at the 26th Annual AACD Scientific Session. With more and more companies getting involved in the innovation and competing in the marketplace, it will become more mainstream and will become a standard of care that will impact many people’s lives as did other consumer products, such as computers, cell phones, and navigation systems, etc.
Digital impressions have not only come on the scene, but numerous studies have shown them to yield absolutely accurate impressions. Assuming the preparation has clear margins and proper body design, the digital systems read them perfectly. The dentist or laboratory can easily mark the margins on the screen, often automatically, with the software provided. Information about undercuts and occlusal clearance is readily available to the practitioner with the software. The discrepancies of plaster water/powder ratios are eliminated, and chipped plaster margins or scraped contacts on stone models as the technician manipulates the wax, casting, or other materials, are all eliminated. The ultimate test is the seating of the restoration, which dentists are reporting precise margins and contacts in the vast majority of cases. There are of course laboratory/university studies that have verified these results, but the day-to-day reported results come from the trenches.
Many practitioners, however, report that they can get these same clinical results with traditional impressions. Much research has been done in developing impression materials with a variety of viscosities, wetting, hydrophilic/phobic properties, and more. A good practitioner can see if the material set properly, captured the margins, did not have any pulls, has enough occlusal clearance, etc, before sending it off to the laboratory. The standard of care right now and in the near foreseeable future is the proper fit of the restoration, not the vehicle to get there. We have reached a point now where these digital systems have verified the process, so a practitioner’s choice is one of personal preference. Our profession is presented with numerous tools to achieve diagnoses and results, but the bottom line rests in the hands and brains of the operators.
More than 20 years ago, Professor Mörmann at the University of Zurich, Switzerland, invented the CEREC® unit, allowing clinicians to fabricate restorations from a digitized replica of a prepared tooth on a computer screen. This technology pioneered the way for other manufacturers to develop various computer-based scanning methods that replace the use of traditional impression materials. Numerous studies in the literature validate the accuracy of the digital impression and its use at the chair and in the laboratory.
Speaking as a dentist/laboratory technician, a downside to traditional impressions is the inability to view flaws in the impression until the stone model is fabricated. One of the major advantages of digital impressions is that they allow the clinician to view the virtual model on the computer screen and detect inconsistencies in the preparation design before conclusion of that step. Digital impressions will alter dentistry as it is practiced today.
Digital impression scanners will be welcomed and will replace traditional methods as our increasingly “instant result” oriented mentality demands it. Yes, they will become the standard of care.
About the Author
Richard J. Simonsen, DDS, MS
Dr. Simonsen is founding dean, professor, and senior consultant in the College of Dental Medicine at Midwestern University.
Pinhas Adar, MDT, CDT
Mr. Adar is the owner and operator of Oral Design Center in Atlanta, Georgia.
Paul Feuerstein, DMD
Dr. Feuerstein is in general practice in North Billerica, Massachusetts.
Gregg A. Helvey, DDS
Dr. Helvey is an adjunct associate professor at Virginia Commonwealth University School of Dentistry in Richmond, Virginia, and has a private practice in Middleburg, Virginia.