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Dr Janos Vág believes that industry standards could help make intra-oral scanning solutions easier to compare, and studies measuring their efficacy more helpful and reliable. (Image: Semmelweis University)

“There must be academic proof that[…]digital dental tools are really reliable”

By Mari Koivunen, Finland
June 07, 2021

HELSINKI, Finland: Dr Janos Vág became a dentist out of necessity, but he would have preferred to have become a computer science engineer. However, when it was time to choose his educational path in 1989, there were few opportunities for engineers. His father, a dentist, suggested that he could make use of his scientific and technical interests in dentistry as well, so Vág decided to follow in his father’s footsteps.

Indeed, for the past decade, Vág has also been able to combine his interest in computer science with his profession in following the evolution of digital dentistry. Working as a clinical associate professor and head of the conservative dentistry department at Semmelweis University in Budapest in Hungary, Vág has established an impressive academic track record, having published 49 articles—with 370 citations—in peer-reviewed journals.

In addition to his academic research, Vág has a great deal of clinical experience. For five years, he worked at a dental practice, focusing only on clinical work. Today, he practises as a conservative dentist with an emphasis on restorative dentistry and endodontics. He also performs oral surgery and prosthetic treatments—it is common in Hungary for dental specialists to cover larger treatment areas.

Digital dentistry makes work fun

Although digital dentistry has been an industry buzzword for several years now, Vág said that going digital is still not on the agenda for many dentists.

In Dr Janos Vág's view, digital workflows are yet to be integrated into many dental practices across the globe, despite their obvious benefits. (Image: Semmelweis University)

“Using digital workflows will completely change the work at the dental practice,” he noted. “However, most dentists are still not taking any steps to becoming digital dentists. This is not only the case in Hungary, but in the US and on a global scale as well.”

He added: “In dentistry, we should be ready for new things that might not be beneficial in the first few months, but are good fun and make our work much better. Through these investments, dentists can also gain more patients, who might never go back to their previous dentists if they lack the technology.”

Starting from September, undergraduate students at Semmelweis University will learn how to make inlays, onlays and single crowns using an array of CAD/CAM solutions that include an intra-oral scanner, design software and a milling machine. The goal is to teach students how to prepare a tooth for scanning and digital restorative design, according to Vág. “Fortunately, digital dentistry is not the future; it is the present,” he said.

The need for academic proof

While some dentists are not even considering going digital, others are ahead of the existing academic research in their use of digital dentistry. They immediately try out new technology and find out by themselves how to make best use of it. “Some dentists already manufacture, for example, complex bridges using only digital impressions as the basis,” Vág said.

“[D]igital dentistry is not the future; it is the present”

“At the same time, they wonder why we are even studying the scanners, because they have no issues with their treatments whatsoever. But if you want to get the majority of dentists to go digital, there must be academic proof that intra-oral scanners and other digital dental tools are really reliable instruments,” he emphasised.

According to Dr Janos Vág, the dental industry "needs standardised methods for testing intra-oral scanners". (Image: Semmelweis University)

Vág believes that it is important to conduct research on intra-oral scanners, since general dentists cannot otherwise really judge trueness and accuracy, even though they can easily compare other characteristics, such as the weight of the scanner or usability of the scanning software.

Currently, however, it is difficult for dental professionals to make conclusions based on research findings. For the past few years, Vág has studied the differences between intra-oral scanners in precision and trueness. He has found that it is almost impossible to perform any comparisons and meta-analyses between the scanner studies mainly because most studies use different methods, making the data and results incomparable.

“From the scanning set-up to the superimposition analyses and statistics—all studies are so different that they cannot be compared,” he explained.

According to Vág, it is obvious that a 10-year-old scanner cannot be compared to a recently introduced scanner, as there has been rapid technological development in that time. However, this conclusion cannot be made based on the research alone owing to varying methodologies.

Industry standards could help make studies more helpful and reliable

To tackle the problem of incomparable studies, Vág suggests that future studies, journals and companies should employ standardised tables for each new scanner and data set used in the study.

“For example, there are standardised ISO sheets for testing dental filling materials, which everyone must follow for every measurement, such as strength and flowability,” he said.

“Our industry needs standardised methods for testing intra-oral scanners as well—especially now, when differences between the devices are subtle but nonetheless significant for the treatment outcome,” Vág added.

Currently, it is also difficult to interpret the results of the intra-oral scanner studies for practical clinical work owing to the lack of a common methodology. Often there are only statistical differences in the study results, and these do not affect the end result of a treatment.

Vág noted: “If the trueness of one scanner is 50 μm, the dentist wonders if it could mean that there will be 50 μm gaps in a bridge manufactured using those intra-oral scans. The answer is no, even if the milling error is assumed to be zero, because the measurement method does not give a clinically meaningful value. We cannot actually say for sure. Additionally, the fabrication process includes so many different steps that can affect the outcome.”

Current research

Vág recently authored a paper reporting on research in which he and a group of other researchers studied the effect of software updates and materials for intra-oral scanners. According to him, it was surprising to learn how little these matters had been studied before, and the analysis showed that they could have a significant impact on study results.

“It was surprising, because many researchers use different in vitro models to test intra-oral scanners, and they never even consider that the materials of the models might make a difference,” he said. “At the same time, everybody knows from experience that software updates can make a huge difference. It can turn a scanner into a completely new device, but its effect had still not been studied.”

“[I]f you want to get the majority of dentists to go digital, there must be academic proof that intra-oral scanners and other digital dental tools are really reliable instruments”

Although the impact of materials and software updates proved to be notable in the study, the results do not mean that intra-oral scanner accuracy would not yet be sufficient for all indications or full-arch scans. In contrast, the general problem with scientific studies is the time it takes for them to be published, during which a scanning system’s software might have been updated several times.

“The process from creating the experiment to analysing the results and writing the paper takes a long time,” Vág said.

“When a study is published, the data might already be out of date due to software updates. This way, a scanner tested in a study might already be much better than what we see in the literature,” he added.

Academic research is nevertheless still needed to convince the masses of the reliability of digital dental solutions. “Once there is no more feedback from clinicians, meaning every restoration fits, there will be no more need for intra-oral scanner accuracy research,” Vág declared.

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