Digital impressions: Ready for their close-up?

October 24, 2018

Digital impressions entered the market almost three decades ago, but adoption rates have been slow. Is now the time for digital impressions?

It has been 30 years since the first digital impressioning systems entered the market. The same decade that brought us Pac-Man, the smartwatch and the Pet Rock introduced us to the intraoral scanner. It also presented the idea that taking pictures in the oral cavity and stitching them together with software could produce images that would facilitate dental restorations and replace a tray of impression material.

Digital impressions have changed quite a bit since the 1980s. The technology processes faster, the wands are smaller and more comfortable in the mouth, and the scans are more detailed than they were back then. Plus, you can access them from your smartphone if you want. Best of all, you no longer have to sell that vintage Swatch collection on eBay to raise funds to buy one.

Despite these improvements over the past three decades and the increasing adoption of digital impressions in dental practices, traditional impressions are still more prevalent than digital impressions in the dental industry.

So what’s the story? Should intraoral scanners replace traditional impression material and trays? What benefits can one expect from using the technology and should dental professionals invest? Are digital impressions ready for their close-up?

We talked to several industry experts about the state of digital impressions today. Here’s what they had to say.

Digital impressions are past ready for prime time

“This is the future,” says Dr. John Flucke, DDS, and Technology Editor for Dental Products Report. “Digital is the future; impressions are the past. Impressions are like black-and-white TV or a modem.”

Dr. Flucke has been in private practice in Lee’s Summit, Missouri, for nearly 30 years and has been using digital impressions for the last 10. He has never regretted the investment.

“From the day I bought the machine, I was glad I did it,” he says. “The only reason I can think of not to have a digital impression system is if you can’t afford it. Other than that, there is not one advantage that traditional impressions have over digital. Digital wins, hands down.”

“It’s another piece of technology making dentistry easier, better and faster. People are adopting it and marketing that they use it. But still traditional impressions have a big place in the market,” says Dr. Jason Goodchild, DMD, director of clinical affairs for Premier Dental Products Company.

Dr. Goodchild says it helps that the trend toward moving to digital impressions means that they can be used for a broader array of treatment areas than before. In the past, digital impressions were used for inlays, onlays, and the occasional crown. However, now dental professionals can use digital impressions for clear aligner therapy, multiple-unit crown or bridge, implant planning, and even full denture treatments, to name a few. Additional applications emerge all the time for the techy dentist. For example, scanners integrate with software and imaging technology.

“You have scanning integrating with cone beam imaging and software that puts it together and helps with restorative or clear aligner planning,” Dr. Goodchild says. “You are getting lots of integration with other pieces of technology, which is exciting for planning and showing patients what’s possible as well as education and diagnosing.”

Dr. Nathaniel Lawson, DMD, Ph.D., division director of the division of biomaterials at the UAB School of Dentistry, thinks many of the new scanners are fast and easy to use. He also says the elimination of powder from most systems and the introduction of color scans improved the experience for dental professionals.

“Digital impressions are extremely accurate for single-unit crowns, assuming the dentist has performed good tissue retraction,” Dr. Lawson says. “Now full-arch scans are becoming more accurate, even those including edentulous areas. This allows for the possibility of digital impressioning for partial dentures.”

Josh Gall, general manager of Axi Dental Laboratory, has been working in labs for the past 20 years. He works with all types of doctors, so he says he gets to see everything. Many of his digital impressions come from newer dentists and the group practices that team up and share the expenses. Also, he sees them from the tech-savvy doctors who want to be on the cutting-edge of technology, to have the latest and greatest.

However, Gall says he receives more physical impressions than digital ones. He feels like the reasons are a combination of a generational stage of career, personal preference, and expense.

“There are still a lot of Baby Boomer dentists that prefer old-school impressions or that maybe are midway or three-quarters through their career and don’t want the added expense of digital impressions. They don’t want to take on a $60,000 expense at this stage if they are going to retire soon,” Gall says.

Tija Hunter, CDA, agrees that intraoral scanners are still not commonplace, but that in another 20 years or sooner, they will be. She says the new graduates use them in school and want them when they start practicing.

“These kids are video game kids. They were raised on video games and raised on technology. They adapt to it so much easier,” Hunter says. “We are going to see a huge shift in the next several years because of those video game kids.”

Dr. Goodchild also recognizes that the transition could be generational. As more dental schools include digital scanning in the curriculums, graduates will expect to use it when they start their practice.

“It will be a wave of digital impressions that comes over us in the next 10, 20, 30 years, just as the older dentists accustomed to impressions retire,” Dr. Goodchild says, noting that Creighton University School of Dentistry, where he’s a clinical instructor, now has 38 acquisition units and 24 milling stations as part of a significant technology curriculum. “Lots of schools are going the same way. When students apply to these schools, they are looking for an education in these technologies knowing that when they get out, they will be equipped to join a practice and jump in and use them.”

Dr. Goodchild says the data regarding penetration of digital scanning indicates traditional impressions are still more prevalent than digital impressions. However, the growing number of players in the field have increased the competition and, as a result, the machines are improving and the learning curve is getting less steep. The cost of entry has also gone down, which makes it easier for doctors to convert their practices if they want all the advantages digital impressions offer. He feels the trend is toward digital impressions long-term even if traditional impressions rule the day today.

“We are moving in that direction, but it’s just slow. Dentists can be slow to change and overcome the inertia of existing procedures and materials that ‘work well in their hands,’” Dr. Goodchild says.

“They are past ready for prime time,” Dr. Flucke agrees. “Prime time is now. I truly believe that.”

The benefits far outweigh the drawbacks

Per all our experts, the most significant benefit of undertaking a digital impression is the improvement in the patient experience. It’s no secret that patients don’t love fighting the gag reflex while the impression tray is in place. Patients aren’t fans of the impression material either, despite considerable improvements in set times that shorten the impression process, viscosity adjustments that prevent dripping down the patients’ throats, and flavorings to make it taste better.

One study from January 2018 in The Open Dentistry Journal showed that when it came to choosing a preference between traditional and digital impressions, the participants unanimously chose digital 100 percent over conventional impressions.¹

“From a patient standpoint, digital scanning is a whole lot better,” Dr. Goodchild says.

“Nobody wants the goop,” Dr. Flucke agrees.

However, another enormous advantage digital impressions have over traditional that Dr. Goodchild points out is how they affect the workflow with the lab. Better communication with the lab, fast transfer of the images, and quick return of lab feedback increase efficiencies chairside that translate back to the patient as well.

Gall names predictability as the most significant advantage he experiences when working with digital impressions. It allows a lab to identify potential issues or concerns immediately, even before any model work is fabricated. He also appreciates how digital workflows allow him to plan cases with the dentist because changes to the digital design can occur before his technician builds the restoration. It avoids remakes and delays in the final placement.

“After we receive the digital scan or after we receive the model and scan it on our end, we can get a nice clear digital view of the case that we are going to be doing, like an esthetic veneer case or even a full-arch smile makeover. We can then send some images of that designed case on the computer to the doctor to view and say, ‘You know what? The centrals look a little too short. Let’s make them a little longer, or maybe let’s round the incisal edges a bit more,’” Gall explains. “You can do all that digitally with a couple of clicks as opposed to wasting the time of the technician creating all of those restorations first and then having to adjust them later.”

Gall says eliminating the need to adjust already completed restorations, like full-contour zirconia crowns, also preserves the integrity and the shade matching of the restorative material. It also decreases the patient time in the chair. Gall says if the dentist uses digital impressions and communicates with the lab early and often, the patient could have a full-mouth restoration in as little as three visits. With traditional impressions, it could take as many as six visits.

“In any case, using digital impressions just decreases the timeline, increases predictability and shortens the patient time in the chair. As a patient, no one wants to be in a dental chair longer than necessary, especially sitting through a lot of adjustments to get it the way you hoped it would be. All of that can be avoided if you can see it all beforehand and be sure you are getting what you are expecting,” Gall says.

Dr. Goodchild agrees that digital scans streamline the treatment planning and collaboration with the lab and patient and set up the outcome for success. He also appreciates the ability to integrate digital impressions with other technology and imaging, particularly for large-scale restorative work that involves a specialist, like a periodontist or other practitioners.

“Thirty years ago, you would talk to a patient about eight veneers or crowns or a bridge, whatever, but there was no real way of involving the patient in the process,” Dr. Goodchild says. “Now you show them what it is going to look like and why it has to be a certain way. Patients become real partners in the diagnostic process.”

He’s also keen on the real-time feedback you get from many of the systems. From rating whether the impression was good to assess whether you’ve reduced the tooth enough, many of the systems have prep tutorials or prep guides. Some even have alerts that flash red and direct the dental professional to rescan or reduce the tooth more.

“It may not be appropriate for every crown, but you get enough feedback that you might be able to fix it, or the system could point you in another direction. It’s amazing technology,” Dr. Goodchild says.

Dr. Goodchild also likes the ability to store a scan, which makes re-impressioning easier as well as eliminates casts in some cases. “With digital CAD/CAM, the optical scan goes right into the mill,” he says.

Dr. Flucke appreciates the accuracy produced by today’s digital impressions. Many digital impression systems will not allow you to send scans if they have distortions or don’t meet the system’s accuracy standards. With traditional impressions, there’s no gatekeeper for subpar restorations. Dr. Flucke says this accuracy with digital impressions minimizes the amount of time you spend adjusting a restoration for your patient.

“When they come back from the lab, the amount of time you spend at the cementation appointment is minimal. We don’t adjust these restorations much because you don’t have to. We sometimes do, but it is way less than it is with traditional systems,” Dr. Flucke explains.

Hunter thinks that the detail a digital impression produces is key to the precision of the fit.

“When you can take that little tooth and take a picture of it and blow it up to 500 times its size, you can see your margins better,” she says. “You see every little nook and cranny, so whether you are making the restoration or sending it to a lab to produce, the fit is going to be so incredibly accurate, so much more accurate than a traditional impression could ever be.”

Dr. Lawson says the most significant advantage of digital impressions is how proximal and occlusal contacts are reliably achieved for crowns and realized during the try-in. He attributes this accuracy to eliminate the errors that occur with pouring and mounting casts for restoration.

“Digital impressions allow the dentist to improve the quality of his or her preparation by viewing the occlusal clearance and a magnified view of preparation while the patient is still in the chair,” Dr. Lawson says.

Also, Dr. Lawson thinks the practical advantages, such as faster and lower cost production from the lab and the digital record that you can save, are significant.

Traditional impressions have their place - for now

Despite the many advantages our experts shared, many of them feel traditional impressions still have their place. However, as the technology improves, even those areas might prove conventional impressions have run their course.

The one area most of the experts agree that traditional impressions are superior to digital impressions is when the margins are subgingival.

“I still prefer to take a traditional impression when my crown margins are more than about 1 mm subgingival. Impression material is able to slightly displace gingival tissue, which cannot be achieved with a digital scan,” Dr. Lawson explains.

Gall agrees that when the margins are questionable or not clear, a traditional impression might be better, for now. Also, when there’s a lot of decay or other trauma in the mouth, physical impressions might be better than digital.

“When you have a deep margin or some tricky tissue with the prep or something, there is still a need for traditional impressions to be there,” Gall explains. “Or maybe it’s just the perfect tooth that is just right at the gum line with visible margins, but you get the scan done and it doesn’t translate to the lab for some reason.”

Trending article: How intraoral scanning can open up the dental workflow

However, Gall says that there are far fewer computer glitches than physical impressions that aren’t ideal.

Dr. Flucke rarely takes traditional impressions, but he does when the patient has a removable partial denture and the crown he’s placing is the retainer tooth for it.

“The machine does not know what to do when you scan that with the partial in place. The machine just can’t do that. It will someday, but they aren’t there yet,” he says.

Digital impressions in action: How to use an intraoral digital impression scanner for restorative dentistry

Even though he worries about jinxing it, Dr. Flucke says he has taken only two traditional impressions over the past year.

“I hate to say that because that means on Monday, I’ll have to go in and do five or something like that or other nonsense,” he says, laughing.

Part of the reason he does so few is his partner handles the dentures in their practice. They still take traditional impressions for dentures; however, Dr. Flucke has had success using digital impressions with partials. He highlights one case in which his patient had a cyst in his maxilla that required extraction of teeth #2, 3, 4, and 5 on the upper right. Because of the surgery on the cyst, the remaining bone and tissue didn’t have a uniform surface. To compound this, the patient had a sensitive gag reflex.

“We tried to do a partial using the traditional material, but it didn’t work,” Dr. Flucke explains.

Dr. Flucke scanned his entire mouth, the upper and lower arch, and created models from the scan. Then he built the partial off the scans. It worked.

“Given the clinical situation, I was hoping to get something useable, and I ended up getting something I was really proud of. So I think I will always scan for partials,” Dr. Flucke says.

Hunter says she would never want to make a traditional impression over a digital scan.

“Patients hate it, it’s cumbersome, and it tastes awful,” she says. “Give me a wand anytime to take a digital and I will do it.”

Overcoming the fear of change

Our experts all agree that technology advances better, safer and faster dentistry. With digital impressions, doctors can plan and diagnose easier than with traditional impressions, as well as communicate better with the lab and other practitioners. New technologies on the horizon can expand the practice even further, with digital scanning as one of the foundational elements.

Some people, however, will never change.

Dr. Goodchild says that dentists are creatures of habit. His uncle was a dentist, and until the day he retired in the early 2000s he used rubber-based impression material.

“Polysulfide. That was the most disgusting stuff in the world. It took like six or seven minutes to set, but it was dirt cheap and also very accurate,” Dr. Goodchild says.

Dr. Goodchild says his uncle never considered switching because it would cost him a lot of money and he was going to have to learn a whole new system. “My uncle would say, ‘My crowns all fit. They look great, and they are working in the patient’s mouth. Why do I need to change to digital scanning?’”

Dr. Flucke was a psychology major before he decided to study dentistry. He has always been fascinated by behavior and why we do what we do. He says that human beings are creatures of habit and comfort. One of the hardest things to overcome with new or disruptive technology, especially in dentistry, is to get people to try it.

Change is difficult. If people are having success, they don’t want to change because they don’t want to lose their advantage. People also don’t want to invest in a technology that has a learning curve and that they might struggle with initially. This thinking is compounded for doctors who don’t want their patients to lose confidence in them should the doctor struggle and appear incompetent with the scanner technology.

“People’s response is, ‘It is working great the way it is,’” Dr. Flucke explains. “Even changing impression material, if they are having success, they don’t want to change.”

“Unfortunately, a lot of people are afraid of technology, so they don’t embrace it,” Hunter adds. “But if you learn it and understand it, you will be amazed at what you are going to accomplish.”

She also suggests for doctors who don’t want to invest the time in learning the technology to delegate it to the assistants. In Missouri, Hunter can do the scans for the practice. The doctor then takes a closer look at any areas of concern.

“If they can do it legally, let the assistant do it. You don’t have to understand it. They will do it for you,” Hunter says.

Dr. Goodchild thinks that doctors who are reluctant to switch to digital impressions might consider bringing in an associate, perhaps a new graduate who was trained on the technology in school. Another suggestion is to attend a continuing education course about digital impressions and digital workflow.

“If you are skeptical, we all have to learn new stuff. What better way than with CE on something you want to do?” he says.

To invest or not invest? That is the question

Our experts all say that the price point for scanners has come down over the years. However, they all agree that one of the most common obstacles for those practices that haven’t transitioned to digital impressions is cost.

Dr. Flucke says there’s not a financial advantage regarding return on investment (ROI) for digital impression systems. However, there’s not a financial disadvantage either. He compares it to swapping one dollar for another since practices are already paying for impression material, and they often don’t realize how much they pay for it. However, when they see a purchase price for $20,000 to $40,000 for a scanner, they balk at the expense.

“Digital says pay me up front and then I will be cheap. Material wants a payment every month in smaller chunks for the rest of your career,” Dr. Flucke says. “It’s like alimony. They want the money every month for as long as you live.”

Dr. Goodchild agrees that busy general, prosthetic and restorative practices will likely have similar expenses with their scanner as they do with material and lab costs.

“It used to be astronomically expensive to get into integrating scanning and milling in your practice. It’s coming down now and it’s rivaling practices that are busy, although it is still significant,” Dr. Goodchild explains. “It’s getting better, but it’s still expensive compared to what you can get with a cheap tray and a cheap impression material.”

“But I would caution the dentist from selecting a scanner for price alone,” Dr. Lawson says. “If the scanner is not easy to use, there is a chance it will get stored in a closet.”

Gall thinks if more of the manufacturers, or even distributors, would explore a way for dentists to try working hands-on with a scanner with no obligation to buy it, it could help overcome the price objection some dentists have for the systems.

“The cost is keeping some dentists from pulling the trigger. If they got their hands on one and delivered a case or two first, they might be more open to taking the plunge and getting into this type of dentistry,” Gall says.

Gall understands why some doctors might be reluctant to get into digital impressions. He was a self-described digital impressions skeptic earlier in his career, too. When digital impressions were first introduced, he couldn’t imagine that a picture of a tooth would be as useful as a model he could hold, feel and check.

“I wasn’t sure how I was going to produce something tangible from something that was intangible,” Gall says. “We have come a long way since then with millions of cases in the mouth. That’s the proof right there that this works.”

Reference

Mangano, Alessandro et al. “Conventional Vs Digital Impressions: Acceptability, Treatment Comfort and Stress Among Young Orthodontic Patients.” The Open Dentistry Journal 12 (2018): 118–124. PMC. Web. 30 Aug. 2018.