Labs Lead the Way

It’s not hard to understand why laboratories would like dentists to get on board with digital impressions for appropriate cases. As Inside Dental Technology Editor-in-Chief Pam Johnson observes, the laboratory industry itself is quickly transitioning over to a digital workflow. Whether or not dentists are aware of it, the physical impressions they send are routinely used to create the digital data the laboratory needs to produce a restoration, a process that involves infection control and model preparation prior to scanning.

“With 30% fewer laboratories tasked with making more restorations, automated processes and digital manufacturing have become especially important. For this reason, it becomes much more efficient for the laboratory if the dentist were to send digital versus analog data,” says Johnson.

The Question of Quality

While Jim Shuck, vice president of sales and marketing for Glidewell Laboratories, hesitates to claim that a digital impression is superior to a well-done traditional impression. His Newport Beach, California, laboratory has compiled statistics comparing the return rates of CAD/CAM-processed monolithic restorations made from digital versus conventional impressions for the three main reasons dentist return crowns—margin errors, occlusal adjustments, and fit issues related to tooth preparation.

“If we get digital impression scans and make model-free crowns, we have documented that we have a 47% reduction in crown remakes for margin errors, a 32% reduction in remakes due to fit problems, and a 34% reduction in remakes for occlusal issues—all of which relate directly back to the impression/stone models and other analog variables,” says Shuck. He notes that secondary decay due to margin and fit issues can lead to restoration failure. He says those numbers “are all compelling reasons labs want dentists to provide digital impressions.”

Andrew Koenigsberg, DDS, owner and founder of Gallery 57 Dental in New York, New York, suggests these findings are likely rooted both in problems inherent in the traditional impressioning process and the failure, for whatever reason, of too many dentists to provide adequate impressions for their laboratories. “Well-made manual and digital impressions both work well. But the point is that the majority of manual impressions are inadequate,” he explains. “There are several reasons for this that are inherent in the process. Some of the problems are bubbles, pulls, and too little material in areas. Another problem is that impressions are very difficult to assess chairside, so that inadequacies are often not recognized until the model is poured. At this point, making corrections is difficult and expensive. In contrast, digital impressions give immediate feedback and are easily corrected.”

He also points out that as more materials are being manufactured digitally, a digital impression saves time, labor, and material, all of which lead to lower costs and improved profit margins.

The Lag in Adoption by Dentists

While Shuck also reports that the number of dentists sending digital impressions has quintupled in the past 2 years, this uptick, he says, represents only 5% of dentists and pertains only to fixed restorations.

Lee Culp, CDT, says the main hurdles to widespread adoption of digital impressioning by dentists remain price and a learning curve. The latter, he says, relates to re-learning tissue management approaches that were made less necessary with the introduction of advanced impression materials, coupled with labs’ increased proficiency “at guessing where the margins are.”

Further, many dentists have what Koenigsberg calls an attitude of “if it’s not broke, don’t fix it,” about which he says, “Of course, this is ironic because conventional impressioning is ‘broken.’ More than half of impressions don’t give the labs the information they need, and materials and remakes are expensive. However, impressions are the devil that doctors know. They are in their comfort zone and have learned to manage within the limitations of conventional impressions, limitations that include errors due to distortion and implant analog rotation.”

Both Koenigsberg and Martin Jablow, DMD, an expert on dental technology and materials from Woodbridge, New Jersey, believe navigating the learning curve is easier than in the past. “Without powder, a dentist should be competent in just a few hours of practice and improve from there,” says Koenigsberg. Jablow further notes that doctors may not realize they are already up to speed. “Correct preparation and tissue management methods—using retraction cords, lasers, etc, that make subgingival margins clearly visible to the camera—are identical to those needed for all the newer impression materials. If you’re currently doing e.max or zirconia crowns, you have no learning curve—you know how to prep. In many cases now, those preps are supergingival, which are easy to scan.”

Limitations of Digital Impressions

Perhaps a more legitimate objection to making a significant financial investment is that it is not yet possible to impress all teeth digitally. They are generally limited to crown and bridge cases, as well as implants. Jablow says the percentage of teeth that can be impressed has been estimated to be as low as 50%, but more typically is considered to be in the 70% to 80% range with current technology. “They cannot be used in patients who can’t open wide enough to accommodate the wand, those with uncontrolled bleeding, or when restoration margins are deep subginivally,” he explains.

The Time Is Right—and Not Just for Labs

In light of the many advantages cited, Culp definitely believes the time has come for dentists to get on board with digital impressions for appropriate cases. Culp says that intraoral scanning has been around for more than 2 decades, but until very recently it didn’t merit an affirmative response to this question: Is it better, cheaper, and faster than traditional impressions?

“The time is right in terms of ease of use, it’s faster than impressions, and accuracy is better than or equal to modern impression materials,” Culp notes. This assertion, he says, is supported by research studies.

Now, with the new scanners, he says sales reps can look dentists in the eye and feel comfortable claiming those three important benefits. “Now we’re all confident in being able to say the technology is good, that a learning is involved but it’s now equal to or better in terms of being better, cheaper, faster than impression materials,” says Culp.

Of course, there is no denying that it is faster for the lab, but, as Koenigsberg points out, impressions that don’t provide adequate information—especially when they lead to remakes—impair the clinician’s productivity. What’s more, staff can be trained to take on some of the scanning performed by the dentist.

Although determining if digital is better than traditional may be subjective, there is no doubt that the technology is evolving to improve the user experience. Koenigsberg notes there have been important improvements in data capture and software and workflow—especially powder-less video capture. In addition, Johnson notes the improved ease of use and size reduction that can overcome a persistent problem of access to the third lingual molar. She mentions a new scanner by 3M that can actually be placed up against a tooth and one by MFI that is long and slim and can be easily manipulated in the mouth like a handpiece.

“Cheaper” is also in the eye of the beholder. Although there are time and cost savings that accrue, there remains the financial outlay associated with purchase or leasing. All those interviewed recognize that as more companies bring new scanners to market, there will be price pressure, and that price reduction—including elimination of the “click fee” per time –will eventually motivate more doctors to make the investment.

“It’s strictly a price issue now,” says Jablow, who nonetheless expects widespread adoption not only because of price reductions and new technology, including the newer wands, but also because of a changing model for return on investment (ROI) beyond the current systems. “You are trading the cost of the impression material for the cost of the digital impression machine and click fees, so you need to consider whether there will be an appropriate ROI for your office in time and costs. In other words, if you can get a digital impression system that’s $7,000 to $8,000 out the door, with no additional fees, that will create demand and push it.”

In the meantime, Jablow says, dentists should consider their options based on their own individual situation.

Laboratory Incentives

To encourage practitioners to provide digital instead of manual impressions, some laboratories offer a variety of incentives, including rebates and discounts.

Johnson says, according to the National Asso­ciation of Dental Laboratories, “One of 10 labs owns a digital impression device that they either lease out to their top-producing dentists or give them in exchange for a contractual arrangement that any digitally produced impression will go to that lab.”

Efforts by Glidewell—in partnership with Align Technology and 3M—to introduce more dentists to digital impressions, says Shuck, enables dentists to deliver a crown chairside in a single appointment. “Our software takes the data from their iTero or True Definition scanner, proposes a crown, which, after approval, can be milled in the TS-150 chairside mill as either a resin or lithium silicate crown.”

What Glidewell is doing further to accelerate the transition, says Shuck, is offering a stand-alone chairside system he calls a “good point-of-entry”—a chairside mill and scanner for $75,000. This he says will enable dentists to immediately provide chairside 1-hour crowns, but will also enable them to use just the scanner for restorations that require laboratory fabrication—eg, zirconia crowns, which have a 5 to 8 hour sintering cycle, or to go through their labs for more complicated case or anterior work.

Shuck says Glidewell discounts $20 per unit off the list price for all fixed crown and bridge restorations that are made from digital impressions without a model; the client dentist also saves the $7 fee for impression tray shipping to the laboratory.

Eye on the Future

While cost remains the greatest obstacle to widespread adoption now, all agree that digital dentistry will eventually become the norm for a variety of reasons, probably within 5 to 7 years.

Culp believes widespread adoption of impression scanning is still about 5 years away, but he sees momentum building. “The schools are just now engaging in bringing in technology at the undergraduate dental school level, but the trend is evident at meetings, including that of the American College of Prosthodontists, and in an increase in the number of product introductions.”

Johnson says a combination of cost reduction and demand by younger dentists accustomed to new technologies will nudge the trend. She also suggests the possibility that there will be “a tipping point at which laboratories will be so tied to digital workflow that they may start charging dentist for sending a physical impression because of the disruption to workflow and the added costs to convert the physical to digital data.”

Koenigsberg, too, expects widespread adoption due to the growing presence in the dental workforce of dentists who are comfortable with technology. He also expects pressure on private practitioners from the large dental service organizations. “Corporate dentistry will recognize the cost efficiency of digital impressions and implement the technology, forcing private practitioners to follow,” he says.

Conclusion

“There is no question that digital impressions are the future. They are faster, more accurate, and easier—once the learning curve is managed—for restorative, so it is really a question of timing,” concludes Koenigsberg. While he recalls that in the case of x-rays and porcelain-fused-to-metal crowns, adoption of dental technology was slower than expected, he says, things are changing. “We are living in a world where technological innovation and adoption are accepted and long-standing patterns can quickly be disrupted. Doctors don’t want to be caught on the wrong side of service and efficiency, and this is an important factor in deciding when to get on board with digital impressions.”

The First 3 Steps Toward a Digital Workflow

Plan to Start Small

Koenigsberg suggests making the first step a relatively small one. “Tackling just the impression part of the process, without getting involved in the design and production of restorations, does make the learning process less intimidating and overwhelming. Starting with just the impression part of the process simplifies the learning and integration.”

Get Buy-In from the Team

Culp points out that the learning process—even for scan-only digital impressions—should be a team effort. This means making sure everyone is comfortable and engaged with the equipment and the digital workflow. “It’s important to get assistants and staff—depending on the state—on board. All need to know it’s fun and easy and that patients love it,” says Culp. “Dentists need to get comfortable with the workflow; dentists and technicians need to get comfortable with the data transfer, everyone involved should believe it is better and more accurate and that it is the digital workflow of the future.”

Make Training a Group Effort

Shuck believes training dental team members, who may do much of the work with traditional impressions, can further improve the time savings possible using a digital scanner. “If dentists can train staff to do most of the scanning, they can do preparation of the tooth and scan just a small section.” Shuck says familiarizing both clinicians and their staffs with the technology through, for example, an in-office demo, can help change their perception that digital impressions require more work than the familiar traditional method. “This gives them the chance to sit at the machine, use the software, and scan different areas—eg, the preparation, the bite, the opposing.”