Table of Contents

Cover Story
Practice Building
Roundtable
Continuing Education
Implants

Inside Dentistry

July/August 2011, Volume 7, Issue 7
Published by AEGIS Communications

Digital Impressioning

Much of the credit for the boom in the demand for digital dental impressioning systems lies with the dental laboratories. Many dental technicians, to assure that the prospects for their future within the dental industry remain viable, have embraced digitization of impressioning devices, coping and framework design technology, and milling machines capable of producing superior restorations. In many cases, savvy laboratories are convincing their customer dentists to join the digital revolution.

There are two classifications of digital dental-impressioning devices:

  • CAD/CAM devices that include an intraoral digital scanner for capturing impressions of the prepared teeth, as well as synchronized units for both designing and milling the restorations from blocks of ceramic or composite materials
  • Dedicated intraoral digital scanners that capture data that can be sent to laboratories and other facilities, where stereolithic or milled models and dies are created from the data, which are then articulated and sent to dental laboratories for the custom fabrication of the restorations

The leading systems in the realm of CAD/CAM are CEREC® (Sirona Dental Systems, www.sirona.com) and E4D Dentist™ (D4D Technologies, www.d4dtech.com). The dedicated digital impression systems continue to be led by the Cadent iTero™ (Cadent, www.cadent.com) and Lava™ C.O.S. (3M ESPE, www.3mespe.com). A number of other dedicated systems have recently been introduced, including IOS FastScan® (IOS Technologies, www.ios3d.com) and MIA3d Station (Densys3D, www.densys3d.com).

The CEREC® system has undergone several iterations and improvements since its introduction in 1985, the most notable of which was the CEREC AC Connect portal, through which the dentist can take a digital impression and transmit the data to a dental laboratory within Sirona’s network. The dentist can now append additional information to the prescription sent to the laboratory, including supplementary facial photographs, details of the tooth shade, characterization instructions, and details of the occlusal concept. As a result of the precise digital impression created in the patient’s mouth, plus the rapid 1:1 transmission of the model data to the laboratory, it is possible for the dentist to discuss important details with the technician while the patient is still in the chair.

Once the dentist and technician agree on the restoration to be made, the laboratory is able to design the restoration. If needed, the laboratory can order working models from infiniDent®, Sirona’s central production service, or mill the models in-house using the inLab® MC XL milling unit. The restoration can be made on the models, then stained and glazed and sent to the dentist for insertion.

A major advantage of the Sirona inLab® is the ability it offers the dental technician, in most cases, to mill the restoration directly from the digital impression without the need for a physical model, thus saving labor and material costs. In fact, since October 2010, Sirona even eliminated scan fees.

If a dentist only wishes to capture impressions digitally using the Acquisition Center and the CEREC® AC Connect Portal, he or she may do so and can later upgrade the digital impressioning unit to connect to an in-office milling unit, if so desired.

Fewer treatment and processing steps result in fewer sources of error and greater standardization. The predictability of the outcome is enhanced by the dentist’s ability to capture a digital impression without re-takes, because any deficiencies in the impression can be corrected with an additional image or two. Digital impressions offer both better communication between the dentist and the dental technician, and an orientation toward making the impression and restoration fabrication more pleasant for the patient. These benefits improve the image of the dental practice and can thus encourage word-of-mouth generation of new patients.

The E4D Dentist system introduced significant new capabilities in digital impressioning at the March 2011 IDS meeting in Cologne, Germany. The system now provides the dentist with enhanced real-time feedback on scan progress and quality with the new full-screen view and large “live view” (camera) window. Scans with motion or misalignment are automatically discarded, resulting in an extremely sharp, well-defined virtual model without operator intervention.

E4D Sky/DDX data exchange capabilities give the practitioner the ability to send digital impressions to D4D for Design On Site design services, to dental laboratories with the E4D system for design or complete fabrication and characterization, or to send the case to D4D for STL file conversion to send to another system for fabrication. With just a few clicks, the dentist has the full range of design and processing options, all with digital accuracy.

With the additional speed and ease of digital impressioning in the E4D Dentist chairside CAD/CAM system, the whole procedure becomes more efficient and clinically effective. The range of design and production options offers the practitioner the decision to hand over more complex cases to experts, or to increase output without having to add staff or make new investments until the higher demand is sustained.

Another advantage of the E4D Dentist system is the ability it affords the dentist to capture scan data without the use of a reflective powder. Better speed and accuracy mean more predictable outcomes in terms of overall fit and marginal integrity, as well as efficiency in workflow and scheduling.

Practitioners will also have the confidence that they can reach outside the practice as needed for design and fabrication assistance. With E4D Sky, they will be able to prescribe and deliver the full range of dental materials that are available.

The E4D system offers practitioners a broad range of options for designing and fabricating restorations, which enables them to integrate the technology into their practice to meet their own professional standards and requirements, as well as involving their team in using the technology, and to meet their patients’ needs for care and convenience.

Whether the same visit, same day, next day, next week, designed and fabricated in-house, by D4D, or a favorite laboratory, every option is available. When practitioners have this level of control, integrating the technology is a much smoother process. The technology adapts to the practice, rather than the practice to the technology.

Cadent introduced the iTero 4.0 at the February 2011 Chicago Midwinter Meeting. The iTero 4.0 includes a new custom software interface, real-time model scanning protocol, and fixture level implant scanning for Straumann (www.straumann.us), BIOMET 3i (www.biomet3i.com), 5 Axis (www.5axisdental.com), and Glidewell Implant Solutions (www.glidewelldental.com). The iTero 4.0 also includes an enhanced widescreen HD monitor.

The most significant new change in the iTero for the practitioner is the addition of the Real Time Model (RTM) scanning protocol. This new scanning protocol enables the dentist to see the model building in real time as he or she is scanning, and presents a final high-resolution model within minutes of the completed scanning protocol. By providing the high-resolution model, iTero is able to give the practitioner the ability to mark and make changes to his or her margin prior to sending the case to Cadent and their laboratory.

The system also offers a new eraser function that can remove an area on the preparation margin, occlusal table, or opposing teeth. With this tool, the clinician can make a minor intraoral adjustment, and then rescan only that area to be replaced in the final impression.

iTero’s fixture-level implant scanning is an ideal process for general practitioners, oral surgeons, and periodontists who are placing implants. The powder-free iTero system provides an ideal scanning environment for taking an immediate fixture-level impression at the time of surgery or after surgery, depending on the soft-tissue architecture required. This flexibility allows the clinician the option to have a custom abutment and crown fabricated for seating in one appointment or two, depending on his or her preferences.

The iTero system STL export function also provides the dentist a digital interface with CBCT data through an implant-planning provider such as Anatomage (www.anatomage.com) or Materialise (www.materialise.com). The clinician simply sends the iTero STL file to the provider for integration.

Finally, the most requested integration will be available in the iTero 4.0—Invisalign. The immediate advantage to the clinician is that he or she can replace PVS impressions for Invisalign® with an iTero digital impression. Again, the powder-free scanning environment provides for highly accurate interproximal and soft-tissue scanning, which is extremely important in the Invisalign protocol. Over the next 12 months, Cadent will be developing chairside applications for Invisalign on the iTero scanner that will enhance both the clinician’s interface and patient interface for Invisalign services.

iTero’s powder-free scanning ensures that the clinician starts with an optimal clinical environment. By integrating the iTero digital impression from end to end in any restorative or cosmetic treatment process, the clinician is assured of removing material and process variables that can contribute to unpredictable results for simple restorations, complex restorative and implant cases, and orthodontics. The key to iTero’s success in the practice is that the dentist and the staff embrace the change, follow the structured Cadent training program, and communicate effectively with the dental laboratory.

In 2011, 3M ESPE has introduced a powerful software upgrade for the Lava C.O.S. system, which enables faster, easier full-arch dental impressions. The features of the upgrade include:

  • Easy Scan—an upgrade that allows for more flexible options and fewer wand rotations during the scanning process
  • Scan Rewind—a feature that allows the user to rewind portions of a scan in 10-second increments
  • Smart Scan—software that automatically eliminates erroneous data if a tongue, cheek, or Dri-Angle® is accidentally scanned
  • Occlusal Reduction Tool—a software feature that provides the dentist with a visual map that identifies any under-reduced areas of a tooth preparation

3M ESPE has recently announced new partnerships with leading implant manufacturers, who have joined the Lava Network. A collaboration with BIOMET 3i offers Lava C.O.S. dentists fixture-level scanning of implants and an end-to-end digital implant workflow using BIOMET 3i’s patented Encode® system. This collaboration is expected to take place this summer.

Additionally, a partnership with Straumann and Dental Wings provides two powerful developments. Scanning of implants with the Lava C.O.S. system will now be possible on the Straumann Cares platform, and a common software platform is now established for dental laboratories that will allow for an open-architecture environment.

A dentist’s ultimate goal for implementing new technologies into his or her practice is to provide an improved level of patient care at an affordable price with dental systems that will still be around years from now. The quality of digital dental impressioning systems has been repeatedly demonstrated to be superior to distortable elastic materials. The cost of using such technology has been shown to be comparable to, if not cheaper than, the older elastic impression paradigm. Finally, the continuing high level and rate of collaborations between dental material manufacturers, implant companies, orthodontic systems, dental laboratories, and dentists in the area of digital dental impression systems offers clear evidence that this technology is here to stay.

About the Author

Nathan Birnbaum, DDS, CAGS (Prosth)
Associate Clinical Professor
Prosthodontics and Operative Dentistry
Tufts University School of Dental Medicine
Boston, Massachusetts

Private Practice
Wellesley, Massachusetts
n.birnbaumdds@gmail.com