It’s hard to put into words the overwhelming sadness that our team here has felt ever since Chiwen suddenly left us last Sunday. He was a healthy, 34-year-old and dedicated father of two small children, and had simply been dealt a terrible hand. His work at CEREC Asia was his passion, and has left his mark on every aspect of our accomplishments.

We are lucky to have known Chiwen, and I know I will miss my dear friend very much.

Rest in peace.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

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A Year for Everyone

In 2019, we saw the release of Primescan from Dentsply-Sirona, and it created this sort of awkward situation for a lot of digital dentistry enthusiasts. Prior to this, many have advocated that striving for the most accurate scanner is the fundamental and ethical obligation for dentists from a treatment perspective. With Primescan, we finally achieved accuracy very close to traditional impressions, but it turned out to cost an arm and two legs. To make things more complicated, an updated Medit i500 scanner can achieve a decent accuracy at half price of a 3Shape Trios (the previous reigning champion of accuracy), and a quarter of a price of Primescan.

While this does put a lot of dentists in a bind, from a technological standpoint its all good news, because things can only get better, faster, more accurate, and less expensive (fingers crossed). There is, indeed, something for everyone.

Side Note: Trends and Intrigue

This year, I personally gave 23 lectures, 14 of which were at international venues, and I am just but one member of our CEREC Asia team. The topics that I focus on are primarily chairside anterior esthetics, chairside material selection, and chairside CAD/CAM implantology. Judging by our reception in many different countries, dentists are not just interested in the evolution of digital dentistry, but also acutely aware of the potential that chairside dentistry brings.

The term chairside, if you are unfamiliar, means that our treatment protocols revolve around us, the dentists. For restorative dentistry, this means that we no longer offload part of the workflow (and responsibility) to the dental lab. Instead, our team has in-house technicians that work with us to decide on the most suitable materials and methods for that particular patient. We need more knowledge to make more decisions, and are rewarded with better control of the outcome quality.

But it’s not all positive. Chairside dentistry is a lot of commitment in time, energy, and cost. It’s certainly not for everyone, and for most of the dental professionals in our audience, they are looking for something in between what they’re doing now, and what we’re doing. A way to apply digital dentistry in a gradual manner with more security and less risk. This is a trend being followed by even the most stubborn traditionalists, and in 2019, we saw several notable dentists begrudgingly shift from the conventional impression to intraoral scanners. They’re baby steps, but progression is progression.

For the ambitious, who wished to participate in the chairside world, CEREC Asia has trained over 500 dentists in 2019 in courses ranging from fundamental concepts in scanning and material selection, to advanced techniques in staining and contouring. It is extremely gratifying to see the interest and positive feedback of everyone involved. The train for digital dentistry is going full blast, and it’s stopping for nobody.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

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Table of Contents

We originally wrote this article back in March, immediately following the International Dental Show this year. However, at the time we chose not to release this for reasons I will describe at the very end of this whole article. But due to popular demand, we’re now releasing our original text. Everything until the Last Three Questions section was written in March, but we’ve read it over numerous times, and our opinion stands. Enjoy!

Hsuan. June, 2019.

Foreword: Learning from Our Mistakes

Two years ago, I wrote a piece called Review of Intraoral Scanners at IDS 2017, comparing 14 intraoral scanners at the dental show in Cologne. Based on hands-on first impression data gathered by the CEREC Asia team, we rated each scanner using four criteria: speed, size, ease of use, and scan completion.

Amazingly, that article has since garnered over 200,000 views to date, drawing plenty of comments and questions from dentists and dental technicians around the world. It also spawned a bunch of similar review articles and, more importantly, helped generate discussions on intraoral scanners around the world, particularly in Asia.

At CEREC Digest we pride ourselves in writing investigative articles based on factual evidence. While we are actually not affiliated with Dentsply-Sirona in any way, we are acutely aware of the presumptions that people have based on the “CEREC” in our name. However, we do not consider this a handicap. Instead, it is a constant reminder to go the extra mile and ensure the validity of our claims.

But we are human after all, and some of our decisions, even after all things considered, are still somewhat subjective. Unsurprisingly, the same 2017 article that was so popular also attracted a fairly large wave of criticism, especially from the manufacturers who were ranked low on the list. While most of the complaints were unproductive and self-serving, we acknowledge that a few of them were legitimate concerns.

Over the last year, we’ve discussed internally to see how we can do better, and perhaps make the whole review process more meaningful. So far, we’ve recognized a few places that could be improved, and in this article, we are pleased to show you a new system of rating intraoral scanners that is more clinically relevant.

Cutting to the Chase

If you’re in a hurry and just want a quick summary, here’s the section for you. Since there are many important complications and nuances in our analyses, however, I recommend reading the whole article before you do anything rash, like sending me a stern letter of disagreement.

Without further ado, here are the our overall ratings for the intraoral scanners shown at IDS 2019:

The vertical positions indicate the rankings from top to bottom. The classes do not affect ranking, and are simply for categorical purposes. Read on for more information.

The Big Picture

To say that the intraoral scanner is very important to my work is an understatement. At our modest clinic with 10 dental chairs, we fabricate an average of 500 chairside CADCAM restorations per month. With clinical experience in CEREC, 3Shape, and Planmeca (though substantially less than the other two), I have first-hand accounts of the best (and worst) of these different systems.

Back in 2017 when I last visited IDS with our CEREC Asia team, it felt as if there were only two intraoral scanner systems that were truly clinically viable: the Omnicam from Dentsply-Sirona and the Trios 3 from 3Shape. This is not to say that other scanners are unusable, but they really did leave a lot to be desired. While part of this was reflected in their overall score, there were definitely little things that bothered us, and yet were difficult to quantify in our review.

Has this changed in 2019?

As you would expect, the overall hardware and software quality of intraoral scanners have improved over the last two years. That being said, the overall ranking of the scanners relative to each other, for the most part, did not see drastic changes. This is, after all, complicated technology, and so it’s understandable for development to be incremental. The 3Shape Trios 4 is the prime example of the difficulty in upgrading from a scanner that was already one of the best, the Trios 3.

That is why I was very excited to see new scanners designs showing up at IDS this year, whether they performed well or not. Because it shows that these manufacturers have at least received sufficient demand from the market, or at least enough positive reinforcement to make the investment. I’m talking about scanners such as the Virtuo Vivo from Dental Wing, the Aadva IOS 200 from GC, the X Pro from Kavo, and the Primescan from Dentsply-Sirona. I think it’s quite risky to reinvent new tech, and applaud these companies for trying.

The Difficulty of Rating Scanners

The point system that we used in 2017 provided a quick and easy way to gauge how one IOS performed relative to each other. Here was our 2017 summary.

The system that we used was suitable for a superficial comparison, but consider this: the Planscan Emerald, Carestream CS 3600 and Dental Wings DWOS all received 16 points, so are they equally good?

The DWOS was significantly slower than the other two scanners, yet won serious brownie points for being the smallest of the three. This raises an interesting question: does the size matter if the scanning speed is inadequate?

I would argue that if the scanning speed makes a scanner unsuitable for clinical use, then size is kind of irrelevant. But you don’t have to take my word for it. Of the three scanners that have received the top score of “5” for size, the DWOS was discontinued, and the 3M True Definition was nowhere to be found at IDS. Meanwhile, the iTero scanners are still rapidly gaining market share around the world despite getting punished hard for its size in our rating system. Why? Because it’s actually a decent scanner overall, numbers notwithstanding.

Now what about the CS3600 and the Planscan Emerald, both of which I’ve used on real patients. After spending some time with them, I think Carestream scans are a bit more consistent. However, the design software on the CS 3600 workflow is significantly handicapped when compared to the Planmeca. So if you’re looking to scan, design, and mill your own restorations, Planmeca is actually the better choice between the two. And this nuance is lost with our previous rating system

Once we start factoring in things like scanner weight, touch screen, caries detection, and other supplementary features, the whole pictures becomes something of a mess. Faced with this same struggle last time around, we decided to abandon the complexity in the end. Instead, we went with a generalized but easy to comprehend approach. Clearly, it wasn’t perfect, and a new method of rating scanners was needed for a more meaningful discussion real clinical settings.

A Rating System that is Clinically Relevant

We began by asking ourselves: What do we care most about an intraoral scanner? After our last review article, many people messaged me to complain about the fact that the price wasn’t factored into the rating. Clearly, people think pricing is important, but is it the most important? Would you rather buy a cheap machine that is barely usable, or invest in an expensive one that actually increases clinical productivity?

From my own experience, I argue that usability is the most important. In other words, being able to complete a scan with ease and efficiency is the most basic requirement for an intraoral scanner. Everything else, in comparison, is secondary.

Instead of using arbitrary numbers, however, our team compared notes, analyzed our scanning videos and picked the top scanner based on the three components of scanning efficiency: scanning speed, data capture, and software intelligence. Using our top choice as a reference, we then rated all the other scanners based on these criteria.

Since our rankings are qualitative, we wanted to provide a visual aid for clinicians to reference. Digital scanners are used to replace traditional impressions, so we developed a three-tiered system based on traditional timings for easy reference.

• Tier 3: The scanner is able to complete a full-arch scan and export an STL model successfully, without time limit.
• Tier 2: The scanner is able to complete Tier-3 tasks faster than silicone impressions (around 5 minutes).
• Tier 1: The scanner is able to complete Tier-3 tasks faster than alginate impressions (around 1 minute).

How are the classes defined?

Not all scanners have the same set of functions, and we wanted to show this explicitly in our review. Therefore, we’ve divided them into three different classifications based on system capabilities. However, the intraoral scanners are rated purely on their own merits, and their classifications are not taken into account. The classifications are as follows:

• Class A = The manufacturer offers its own scanner, CAD software, and CAM (milling) unit.
• Class B = The manufacturer offers its own scanner and CAD software only.
• Class C = The manufacturer offers its own scanner only.

It’s like buying a computer: all of them can do word processing, web browsing, and Youtube shenanigans, but some of them are also able to play games, render 3D models, and perform parallel computing. Whether these additional specializations are important to you will depend on what you’re looking for.

Similarly, if you are simply looking to buy a scanner to replace traditional impressions, then any of the classes A, B, and C will do. If, however, you are also thinking of designing your own surgical guides, then you’ll need at least a Class B system. For us here at CEREC Asia, one of our primary focus is on single-visit restoration, and so having a Class A system is imperative for clinical efficacy.

A Word on Scanning Efficiency

The Koenigsegg Agera RS, seen above, holds the current Guinness World Record for fastest street-legal car, capable of reaching an incredible 278 MPH (447 KM/H). But in the real world, getting from A to B is more than just raw horsepower. Instead of a straight road, we have to navigate sharp turns, traffic issues, and weather conditions to reach our destination in one piece. A similar logic can be applied when testing intraoral scanners.

Completing an intraoral scan is not simply a matter of whipping the scanner around as fast as you can. The scanner needs to also consistently acquire useful data for 3D model reconstruction. In the event that the scanner has captured bad data (i.e. tongue, cheeks, fingers, etc…) it needs to be able to fix them, preferably on the fly and without user intervention.

In short, scanning efficiency can be divided into three parts: speed, acquisition, intelligence.

This idea of being able to efficiently complete a scan is so integral to the our clinical experience that we’ve placed it above all else in rating intraoral scanners. In other words, we prefer a scanner that does what it was meant to do, and does it well.

While we’re still on the topic of scanning efficiency, I would like to address a fundamental problem with testing on a model as opposed to a real oral cavity.

As shown at the top in the above graphics, each digital scanner has a theoretical maximum speed that is limited only by its hardware. Unfortunately, this number is meaningless to clinicians because it represents an ideal condition that’s unattainable in real life.

At dental shows, we often go for the easy option: scanning dental models. Digital scanners are particularly good at scanning homogeneous and opaque surfaces, so if you have a hard time scanning models, that’s not a good sign.

Unfortunately, our teeth and restorations are not homogeneous and opaque, but translucent and opalescent. So what can we do to test the scanning efficiency on a heterogeneous mixture of enamel, ceramics, resin, and metal? When you see sales reps scanning themselves at dental shows, that’s essentially what they’re doing. Self scanning shows you how well the scanner is able to pick up real-world data, so it’s a slower but better representation of reality than model scanning.

But that’s not the whole story either. With self-scanning, you can minimize the impact of soft-tissue and environmental interference through a lot of repetitive practice in the same mouth. When we scan a new patient, however, these issues are unpredictable and will inevitably slow you down. You might need to pause scanning and delete some unwanted parts of the 3D model. You might need to stop for fluid evacuation or lens clearing. Some teeth might be hard to reach for certain patients, and you’d have to make adjustments on the fly. In the office, there are plenty of little problems here and there to significantly impact your scanning efficiency.

As far as we could see, the only booth at IDS 2019 with a dental chair setup and actively encouraging visitors to try scanning a real person (other than themselves) was the Primescan at Dentsply-Sirona. Unlike live demonstrations, hands-on scanning cannot be practiced ahead of time, and is the only reliable method to evaluate both the clinical performance and learning curve of an intraoral scanner.

Unfortunately, since most of the manufacturers only offered model scanning, we will stick with that for controlled comparison. As you read the review here and others on the interwebs, however, keep this important detail in mind.

CEREC Primescan

#Disclaimer 2019-06: I wrote this review immediately following IDS in March, but have since used the Primescan routinely at CEREC Asia and our clinic. I’ve decided to not add any additional feedback and experience to my original text so as to be as fair as possible to other scanners.

Primescan is the brand new scanner from Dentsply-Sirona. I’ve written an analytical article on it when it was first announced back in February. In it, I discussed our hands-on experience and tested the manufacturer’s claims on accuracy. For anyone interested, here is the link to the article:

New Kid on the Block: Primescan and What It Means for Current and Potential Users

The claims for Primescan were fast, accurate, and easy to use. We’ve dealt with accuracy quite thoroughly, so just exactly how fast and how easy to use was it to use? Here’s a video followed by our impressions.

Efficiency

• SPEED: Scanning traversal speed was definitely one of the fastest compared to all the other scanners at IDS.
• ACQUISITON: Data capture also feels significantly faster than the Trios 4 and the Omnicam in a single pass, thanks to the Primescan’s large scanner head and depth of field.
• INTELLIGENCE: The AI powering the Primescan is simply amazing. Its ability to fix soft tissues, and other mistakes, makes for scanning experience that is significantly less stressful.

Addressing the Elephant in the Room

Yes, Primescan is a big scanner. When you hold it, the pen grip also feels quite different due to the wider girth, and the size of the scanner head felt almost comically large, especially if you’re comparing it to an Omnicam. If I’m being honest, I thought it looked like a fat Omnicam.

But since we were able actually scan someone intraorally at the booth, it was easy for us to see that the size was not an issue at all. Instead of trying to convey this through paragraphs of exposition, I encourage our readers to try the scanner on a real person and see for yourself. In our opinion, the decrease in mobility is more than made up for by the image capture capabilities and the AI in the software.

Our Verdict

As much as we’ve agnoized over how partial our decision will look, we have concluded that the Primescan is, without a doubt in our mind, the #1 scanner of 2019. While the Omnicam was already one of the fastest scanners available, the clinical efficiency of Primescan is simply unmatched in our tests, especially considering that we also tested on real people. Keep in mind, however, that its price is also unmatched, and not in the good way.

3Shape Trios 4

The Trios 3 tied for top score the last time we were at IDS in 2017. It was fast, relatively easy to use, and was definitely one of the best options available at the time. With the release of Trios 4, we were curious to see how much of an improvement 3Shape was able to make on such a great scanner. The short answer: not much.

Efficiency

• SPEED: The reps kept telling me that the new Trios 4 is faster than Trios 3, but once I pressed them on the details, they weren’t able to pinpoint exactly what made them faster, other than “new hardware and software”. We tried scanning with both generations back to back and I honestly could not tell the difference.
• ACQUISITION: Data capture was on par with the Omnicam in a single pass, and I’m much more proficient with the Omnicam, so extra points to the Trios 4.
• INTELLIGENCE: The AI was very impressive but not as aggressive as the AI in the Primescan. I actually had a special opportunity to scan a live person with the Trios 4, and it was able to remove most, but not all, of the soft tissue interference. Unfortunately, we were supervised and not allowed to film this extra test.

What’s the difference between Trios 4 and Trios 3?

In terms of the core scanning capability, Trios 4 is essentially the same as the Trios 3, but with a bigger battery (if wireless), new scanning tips, and caries detection. During the exhibition, we were told by a sales rep that the Trios 4 is faster and more accurate than the Trios 3, but we couldn’t find anything to support that claim.

After doing some online digging and looking up relevant patents, we are convinced that the Trios 4 is a rehashed Trios 3 with more bells and whistles. Yes, the fluorescence detection was interesting and the infra-red diagnostics was pretty cool, but I would’ve like to see more improvement on the the scanning latency and stability issues.

Our Verdict

The Trios 3, the Trios 4 and the CEREC Omnicam are tied at #2 on our list. In terms of clinical efficiency, the Trios 4 continues the 3Shape legacy of great scanners. As a Class B scanner, 3Shape’s biggest advantage, in my opinion, is actually not just its superb scanner, but also the sheer number of clinical indications covered by their CAD software and modules. The best part is that for €10,000 less, you can get essentially the same scanning experience with the Trios 3.

Changes to the New Omnicam 5.0

During our last review in 2017, we rated the Omnicam and the Trios 3 with the same overall score. This year, with our focus on scanning efficiency, we have given a slight edge to the Omnicam. While the the Trios 3 did receive new software updates, they were not drastic changes. Even the 3Shape sales reps weren’t able to clearly articulate how the Trios 3 had improved, which is understandable as their marketing was heavily focused on the Trios 4.

The Omnicam, on the other hand, has received the new CEREC 5.0 update, powered by the same AI as the Primescan. Not only is acquisition considerably more reliable, but the software is noticeably more intelligent in fixing stitching errors and soft-tissue issues as well. Whereas the Trios focused on extra features like motion jaw tracking and caries detection, Omnicam 5.0 improved its core function. However, since this new version of the Omnicam has yet to be publicly released, we will rank the old Omnicam on our list for now.

Medit i500

Released in 2018, the Medit i500 is the new scanner coming out of South Korea, and is definitely a game-changer in terms of the kind of performance you can get without breaking the bank.

Efficiency

• SPEED: Very impressive scanning speed on the model (see video).
• ACQUISITION: The small scanner head means less data capture overall on every pass pass. The capture speed makes up for this deficiency and is very smooth, but seems to be missing a bit more data than 3Shape and CEREC scanners.
• INTELLIGENCE: We sometimes ran into stitching problems if we didn’t follow the recommended scanning strategy (see video).

Small Reservations About the Medit i500

During our tests, I thought the i500 performed just as well as the Trios 4 in terms of scanning speed and acquisition. In some respects, it almost seemed to scan faster and smoother than the 3Shape scanners. Its software did not seem quite as polished or intelligent, but it did give us decent results for the most of our tests. We’ve placed the i500 in Tier 1, albeit with reservations. As we’ve mentioned earlier, intraoral efficiency is drastically slower than model scanning, and we haven’t been able to test this scanner intraorally (unlike the other scanners in the same tier).

Our Verdict

We’ve decided to place the Medit i500 at a respectable #5 in our Top Ten list. Since there is a three-way tie at #2, the Medit is really #3 in our minds. At €16,000 and without subscription fees, its value is currently unbeatable by any other scanner, especially given its Tier 1 scanning efficiency. If you are on a budget and looking for a no-frills replacement for traditional silicon, the Medit i500 is the perfect balance of cost and performance.

Dental Wings Virtuo Vivo

If we could give out imaginary awards, the Virtuo Vivo would get my vote for Best Newcomer. This was a completely redesigned scanner that looked nothing like the previous iteration, the DWOS. Not gonna lie, I was personally very surprised at how well the Virtuo Vivo actually performed. There was also a live demonstration of intraoral scanning, and it gave us a very good reference for its acquisition capabilities and software intelligence.

Efficiency

• SPEED: The maximum travel speed was surprisingly fast on the Virtuo Vivo. It’s not at the Medit or 3Shape level, but it’s definitely one of the faster and smoothest Tier 2 scanners we tested.
• ACQUISITION: The scanner was able to capture most of what its camera saw, and the scanning field also seemed a bit bigger than average.
• INTELLIGENCE: The software was able to fix basic stitching issues. The live demonstration also showed how it was able to remove some software interference by repeatedly scanning over the same area.

To the Top of Tier Two!

It’s always a difficult call to review a brand-new scanner. On one hand, the Virtuo Vivo had very good speed, smoothness, and acquisition capabilities. Upon first use, we had a feeling that it would probably be ranked right behind the Medit i500. But is it Tier-1 material? The live demonstration did nothing to convince us one way or the other, because it showed good acquisition, but the operator was moving at such a slow pace that there was no way to gauge the actual efficiency. In the end, we asked ourselves: we would be able to scan a full arch in one minute? And the answer was not definitive.

We would be happy to be proven wrong, however. Let us know in the comments below.

Our Verdict

We rank the Virtuo Vivo from Dental Wings at #6 on our list. With its design software and milling unit, this scanner seemed to be a Class A system at first. However, since the milling unit is actually manufactured by Amann-Girbach, it’s technically a similar setup to 3Shape, where part of the workflow is dependent on a third party. At €19,000, it’s a cheaper alternative to 3Shape, albeit at lower but decent performance. If you are already invested in the Dental Wings ecosystem, the Virtuo Vivo is a promising front-end to your CAD/CAM workflow.

iTero element 5D

The iTero element 5D is an incremental update from the previous generation, the iTero element 2. The wand looked very similar to the old design, and there didn’t seem to be much changes made on the actual scanning capabilities. The primary selling point of the element 5D was its ability to perform near-infrared imaging (NIRI). Unlike the 3Shape Trios 4 infrared capture, which requires you to activate image capture individually, the element 5D records all the NIRI data so that you can view it at a later time. Pretty neat!

But what about the core scanning function? Here’s a video

Efficiency

• SPEED: The element 5D uses the essentially the same hardware as the element 2, so there was no appreciable speed improvement. The scanning speed is decent, but not quite at Tier 1 level.
• ACQUISITION: Latency during the scan was very noticeable (see video), but seems to only be a visual effect with no actual negative impact on data capture. The large and deep scanning field of the iTero have always been its strength.
• INTELLIGENCE: The software is able to correct minor stitching problems, but does not seem to have the ability to remove soft-tissue interference. (see video)

Its Ranking Explained

If you saw the iTero scanning video above, you might have noticed that its scanning speed seemed to be a bit slower than other scanners around its rank. In our prolonged tests, we found that the iTero, although not exactly a speed demon, was much more consistent in its data acquisition than Carestream and Planmeca.

Our Verdict

The iTero Element 5D is #7 on our list of top ten scanners. While its definitely clinically viable, the Element 5D’s core scanning efficiency is still not quite Tier 1 level. Unfortunately, its quoted price of over €36,000 puts it in the same price range as the 3Shape Trios 4 and the Omnicam, which are both higher class and higher tier. Even if we’re comparing within the same class, the Medit i500 represents another tough competition for the iTero.

The iTero does, however, have one saving grace, and that is its association with Invisalign. Due to the marketing efforts of from Align Technology, this scanner has done better in sales than its performance would suggest.

Carestream CS 3700

The CS 3700 is yet another evolutionary update to the CS 3600. Unlike the big jump in hardware between the CS 3500 and the CS 3600, this new scanner is essentially the same scanner with a different design for the handles.

Efficiency

• SPEED: It was very difficult to tell the difference between the 3700 and the 3600, even with a side-by-side comparison. The speed was still decent, mind you, but it was definitely one of the slower scanners on our Top Ten list.
• ACQUISITION: For the most part, data capture was very good on the 3D printed model they provided. The scanner produced only a few holes on a single pass, and most of them were embrasures so that was understandable.
• INTELLIGENCE: The software is able to correct minor stitching problems, but does not seem to have the ability to remove soft-tissue interference.

About that Porsche Design

One of the selling points about the CS 3700 is the fact that its new design was by the same minds who designs for Porsche, the sports car manufacturer. But… why? Consider the fact that other companies are adding clinically-relevant functions such as caries detection, fluorescence, and motion capture of occlusion, or just straight up rebuilding a better scanner from scratch. I’m not saying that Porsche engineers have no chance of coming up with a better handle design for an intraoral scanner. In fact, we quite liked it, but is it really the critical detail that’s holding the scanner back?

Our Verdict

We give the new scanner from Carestream the #8 spot. It might seem like the CS 3700 is a step down from the CS 3600, which was ranked at #3 in our 2017 review, but it’s all relative; since most other manufacturers came out with more tangible improvements to their scanner, the CS 3700 felt about exactly the same. However, this device is scheduled for release later this year, so it’s possible that they make last-minute changes for the better.

Planmeca Emerald S

A few years ago, I got to scan, design, and fabricate an onlay for the first time on a class A system. It wasn’t the CEREC Omnicam, but rather the Planscan, the last-gen scanner from Planmeca. However, the nostalgia did nothing to dampen my disappointment when I saw the Emerald S. In keeping with the trend set by 3Shape, iTero, and Carestream, the Emerald S is also an evolutionary update to the previous scanner, the Planmeca Emerald. In other words, don’t expect to see significant changes to the core scanning functionality.

Efficiency

• SPEED: The Emerald S is a fast scanner on the model, and the speed is also very respectable in the mouth. We are able to vouch for its intraoral speed because we’ve used the previous generation, the Emerald, on numerous real patients.
• ACQUISITION: For the most part, the Emerald has very good data capture, both on model and enamel.
• INTELLIGENCE: The ability of the software to fix stitching issues was quite poor. The scanner also had a bit of difficulty resuming a scan once the flow was broken.

The Achilles Heel

For the gamers out there, the Emerald S is the build where the player invested equally on every other stat except for intelligence. So while you have decent hardware, robust design functions, and a very comprehensive workflow, somehow the scanning software gives you the most trouble. The inability to fix some basic stitching errors wouldn’t have been such a big problem if the scanning deformations were rare, but these problems occur quite frequently during our clinical tests with the Emerald (not the “S”).

We wanted to see if things have improved with the new scanner, but were instead told that the scanning issues were due to improper scanning technique. Perhaps. Thought we’d like to note that there were other scanners that performed just fine using the identical scanning techqniue.

Our Verdict

We give the Planmeca Emerald S the #9 spot on our Top Ten list. The scanning speed is almost the same as the iTero, but due to its software issues, you are sometimes forced to stop, delete, and re-scan certain portions. Despite our complaints, however, these are not frequent issues, and we feel that the Emerald S is a about the same efficiency as the Carestream CS 3700. On the plus side, it’s also a decent and less-expensive alternative to the other Class A systems in our list, the CEREC Primescan and the Omnicam.

GC Aadva IOS 200

Out of the top 10 scanners that we’ve reviewed, the new Aadva IOS 200 from GC had the most interesting design. The tip of the scan head sports a simple mirror that’s not completely enclosed, giving the whole thing a very minimalist look. So how well does the scanner perform? Here’s one of our tests during IDS 2019.

Efficiency

• SPEED: The Aadva IOS 200 can reach about the same speed as the Carestream CS 3700 before breaking the scan flow.
• ACQUISITION: The data capture was fairly decent on the stone model, but during a self-scan demonstration the number of holes in each pass increased significantly.
• INTELLIGENCE: The nice lady at the booth mentioned software artificial intelligence, but it looked like basic clean-up capabilities of noisy data.

How does the Aadva IOS 200 compare with the last generation from GC?

The Aadva IOS 200 is definitely a much more efficient scanner overall. It’s faster and has better data capture. The software doesn’t seem to have improved too much, but it’s sensible for manufacturers to use the same software for different hardware. We also gave the last-gen GC scanner, the Aadva IOS, another try this year, and it didn’t really improve very much, at least not enough to enter Tier 2.

Our Verdict

The GC Aadva IOS 200 is a solid #10 on our top-ten list. I can appreciate the new design, but at the moment this device does not seem to have too much advantage over other competitors. As a Class C scanner, it can only perform the most basic functions of an intraoral scanner: scan and export to a third party. Yes, at around 16,000 Euros, the Aadva IOS 200 is one of the less expensive scanners. Unfortunately, the Medit i500 is also around 16,000 Euros, and is a significantly better scanner of the same class. But I wouldn’t count GC out yet, seeing as how they were willing to take a risk and invest in a totally new scanner. Let’s see what they have to offer in 2021.

Last Three Questions

Why was this review article published so late?

I remember sitting in a hotel in Maastricht a few days after IDS in March, proofreading the final draft of this article. More than 5000 words of what our team set out to do, and yet it didn’t feel right. As I was doing additional research to support my claims in the article, I constantly questioned if I was biased in favor of Primescan. Maybe because it’s new and exciting? Maybe because I’m much more familiar with CEREC ecosystem? My draft was able convince everyone on the team except for myself.

In the end, we decided that if we were going make a claim, we’d better be able to prove it. So we waited until after receiving our Primescan, and I tested the crap out of it over the next week. The results were even better than I expected, but by that time a few other websites had copied our format from 2017 and released their review. We didn’t agree with their findings, because all of them seemed have made the exact same mistake we did, but alas it seemed that the window of opportunity had closed.

In the month following IDS in March, I had received a large number of requests online for the 2019 version of our article. As I lectured in many different countries, a lot of the audience member had asked me about our thoughts on different intraoral scanners. Many of them are in the market but don’t have any headway on how to choose. You can probably guess the rest.

Which is the right scanner for me?

Isn’t this the ultimate question? Right now, the choices are becoming diverse and there is a scanner for every need.

Just to list a few: If you are looking for an inexpensive scanner that is easy and efficient, there is the Medit i500. But if you also want to do your own design on a lot of different indications, then the 3Shape TRIOS series are a good choice. For the ultimate system for accurate scanning and chairside restoration, the Primescan currently has no competition, but there’s literally a high price to pay.

But whether it is price, accuracy, or how many indications you can use it for, the one thing that most people overlook is the availability of training and education. Maybe you don’t need too much training for Class C scanners, but if you are considering Class B and A systems, a good community that can support you is paramount.

At CEREC Asia we do a lot of technical and clinical training, but our most popular courses are actually the Marketing and Management lectures for CEREC. People are interested to join the world of digital impression, but are unsure of what to do and how to start. As dentists, most of us don’t have the time to figure stuff out, and having access to good education can help you immensely on riding that learning curve.

What about (INSERT NAME) Scanner?

As I’ve mentioned at the very beginning, our last review article in 2017 has gained over 200,000 views so far. This means 200,000 good exposures for the top scanners, but also 200,000 bad exposures for the bottom scanners.

When my colleague and I planned this project last time, we simply wanted to see how the Omnicam that we use everyday performed relative to other scanners. It was not our intention to damage the reputation of anyone, but rankings dictate winners and losers, and for the latter we frankly didn’t work hard enough to ease the pain.

The fact is, intraoral scanning is not just one kind of technology, but consists of several different approaches to reaching the same goal. Through years of competition, some newer methods have begun to mature while others have been made obsolete. Right now confocal technologies reigns supreme, but who knows what the future will bring.

As both an engineer and a dentist, I can appreciate the manufacturers pouring time and resources for the betterment of patients. This is why for this year, even though we’ve tested almost every single intraoral scanner at IDS, we’ve decided to list only the top ten. For the scanners that did not make it into our review, we sincerely wish them the best of luck and look forward to what they bring to the table next time around.

Conclusion

Thank you for taking the time to read our review and analysis. We’ve tried to be as fair as we could, but I’m sure we’ve made mistakes somewhere. Let us know what you think in the comments below, or contact me some other way, and I will make sure to respond to each of your concerns.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post Our Top Ten Intraoral Scanners of 2019 appeared first on CEREC Digest.

The Dentsply-Sirona Primescan is the brand new intraoral scanner from Dentsply-Sirona. For the dental professionals who are on the fence about joining digital dentistry, the Primescan presents an interesting choice against the CEREC Omnicam and other scanners. For the current CEREC users, on the other hand, social media might have just imploded with a collective “IT’S ABOUT TIME!”

But how much of it is hype, and how much is grounded in practical truth? Over the last weekend in a private meeting, our very own Dr. Michael Tsao spent some time with this new machine and noted both its apparent strengths and weaknesses. In this article, I will attempt to distill our internal discussions and offer some insights and analysis on this fascinating device.

What is Primescan?

You can read all about its technical achievements and specifications on the Dentsply-Sirona website. In short, Primescan promises to be faster, easier to use, and more accurate than the CEREC Omnicam. At face value, these claims might not seem bold or even interesting, since every other major brands of intraoral scanners have said similar things about their scanners. This time, however, it seems like these promises are more than just marketing platitudes, as our analysis will show. But first, let’s talk about some physical comparisons between the Primescan and the Omnicam.

The Interface

The Primescan kept the same kart design as the Omnicam, albeit with some distinct differences in how you control the user interface. The mouse cursor is now controlled with a touch pad, with two smaller regions underneath corresponding to the left and right mouse buttons. For CEREC users accustomed to the old scroll-wheel, it will definitely take some getting used to. Thankfully for Michael, all those years of making Keynote presentations on his Macbook without a mouse is finally paying off.

Not only is the track ball gone, the keyboard is removed as well for a clean and minimalist look. The battery is also apparently larger and actually able to support the use of Primescan without a power socket connection. The new touch screen is also 16:9 instead of 4:3, giving the user plenty more real estate to work with. Personally I’ve had no complaints with the original design on the Omnicam, but these are definitely nice quality-of-life changes.

If you want, you can also control the software via the touchscreen itself. The screen is able to move and tilt like the Surface Studio from Microsoft, offering a very intuitive method of moving the 3D models around. One the most common issues we see from new CEREC users at our training center is their struggle with the track ball. It’s nice to see an update that shows some love for users who are probably already masters of the touch screen on their phones and tablets.

The Scanner

At first glance, the Primescan scanner might be mistaken for an Omnicam due to its similar design and color scheme. But the differences are quite apparent once you hold it in your hand. The scanner head is substantially larger in dimension than its predecessor; the scanning area of the Primescan measures 15 mm by 15 mm, while that of the Omnicam is 10 mm x 11 mm.

One of the biggest problems with small scanning fields on intraoral scanners is that it places computational strain on the stitching process because the amount of image overlap is smaller. After discarding extraneous noise, sometimes there’s simply not sufficient data left for accurate calculations. Therefore, increasing the scanner capture size helps to preserve more data and thus better full-arch accuracy, and as you can see from the video above, the added bulk seemed have no effect on its usability. Though whether this is true for patients with statistically smaller mouths (i.e. Asian females) remains to be seen.

In addition to its larger scanning field, the Primescan also uses specific wavelengths of blue light that, according to Dentsply-Sirona, can more accurately capture the surface data. Don’t confuse this blue light with the CEREC Bluecam, however, as the new Primescan uses a completely new method of image capture. As you will see in our analysis later on in this article, all this technology does seem to make significant differences, at least when compared with the Omnicam.

The Software

Admittedly, one of the changes that I am most excited about is the new design of CEREC 5.0 software. The blue background and button designs used in previous CEREC 4.x definitely looked dated (it was released in 2012, to be fair). Personally, I think they did a good job cleaning up the software interface.

During the event, Dentsply-Sirona placed heavy emphasis on the new A.I. in the CEREC software. A recent example of A.I. (for Artificial Intelligence) in the news is the AlphaStar from Google Deepmind that defeated two of the top Starcraft II players in a game thought to be impossibly complex for artificial intelligence. It was able to achieve this amazing feat by supervised training through millions of games.

But in recent years, the word A.I. has become this overused marketing buzzword that conflates different categories of the technology into one general term. To make things more confusing, “A.I.” can technically refer to any kind of software that mimics intelligence and decision making. The old CEREC 4.6 also had “A.I.”, and look how that turned out.

And that’s why it’s very exciting to see the new CEREC 5.0 A.I., because it is capable of self-learning. So the more time you work with it, the better its automatic margins and restoration designs will be. The even better news is that the learning processes is aggregated and centralized at a main server controlled by Dentsply-Sirona, then distributed to all the end-users. This means that as a new Primescan or Omnicam owner, you can immediately take advantage of the most mature and smartest version of the software, trained by dentists all around the world.

Hands-on Verdicts

So about those three claims made by Dentsply-Sirona, let’s take a look at each one by one.

Is Primescan faster?

Yes. Primescan does feel noticeably faster than the Omnicam, but keep in mind that the Omnicam is currently already one of the fastest scanners available. So how fast do you need, really?

Is Primescan easier to use?

Yes. As a veteran Omnicam user, Michael had no trouble adjusting to the Primescan on the first try. The new scanner’s large imaging area and increased depth of field (up to 20 mm) seems to keep the image capture more continuous without breaks. Note that the scanner is also bulkier and heavier, so if you’re not into heavy scanners this might be a small issue.

Is Primescan more accurate?

Accuracy can be divided into two components: trueness and precision. Trueness is how closely the data conform to reality (or the best approximation of reality), while precision is how closely the data conform to each other. These two concepts are mutually exclusive, and therefore can be tested separately. According to Dentsply-Sirona’s own tests, the Primescan is able to achieve the following accuracy:

A trueness value of 14 µm (microns) means that whatever you scan will be, on average, within 14 microns of the target object. While this is an excellent result, it is not unheard of. In fact, similar numbers have been achieved in other studies by CEREC Omnicam, 3Shape Trios, and whole host of other scanners as shown below:

For global accuracy, the numbers are a bit more interesting. You can think of local accuracy as how good a single restoration fits. Global accuracy, then, is how well a full-mouth appliance (i.e. clear aligners, bite plates, implant frameworks) fits. So an accuracy value as close to zero (perfect representation of reality) is desired.

First, a global trueness of 32 microns is very respectable. For context, a study in 2017 compared four intraoral scanners and found that their global trueness ranged from 45.8 to 61.4 microns.

Now you can definitely find studies that shows even better results for a lot of scanners, like this, this, this, this and this study. Keep in mind, however, that there are a few ways to do global accuracy calculations (but let’s not get into it for now). For the purpose of this discussion, we can get a sense of a scanner’s performance based on relative values, and Primescan’s results are looking pretty good.

But numbers and figures can be misleading, especially those with business and financial implications. So we decided to test it for ourselves.

A Totally Non-Scientific Accuracy Test

Local Accuracy: Resolution

As I mentioned earlier, local accuracy is about how much surface detail can be reproduced accurately. To start off, here is a close-up of two scans by the Omnicam (left), and the Primescan (right).

At this magnification, you can see that the dimples on the buccal surface of the central incisor is better reproduced by the Primescan. Also, near the top right of each scan, the cervical margins are also much more pronounced in the Primescan.

The STL file sizes is a quick way to check the mesh density (or “resolution”) of similar 3D models, and all the files sizes were surprisingly very similar. So how is it possible for Primescan to be more “accurate” if it doesn’t use more data for representation? The following image is the same as the one above, but with the mesh overlay on top.

Notice that even though we could visually see that Primescan had more surface detail, its smoother surfaces use much larger triangular meshes. This allows the STL file to become more dense in places where the detail really matters, like the dimples and the cervical margins.

Assuming that same conversion method to STL is used in both cases, we think that this result has to do with the Primescan capturing lower levels of noise than the Omnicam. Therefore, while the resulting mesh density (or “resolution”) isn’t noticeably different, a better signal-to-noise ratio allows the Primescan to preserve more detail.

Local Accuracy: Sharp Edges

One of the Omnicam’s issues is that the sharp edges (i.e. less than 90 degrees) tend to be more rounded in the scanned result. In fact, there is a study for this particular phenomenon. During the presentation, Dentsply-Sirona also made an effort to point out how the Primescan can capture edge details better. Naturally, we put that claim to the test.

Immediately we can already see a difference in detail between the Omnicam and the Primescan. Notice also that the vertical surfaces are also smoother on the right (Primescan).

If you’ve ever used an Omnicam, you’ll know that a lot of times it has trouble with dark spots, like stains on the enamel, or blood, or magic markers. The dark lettering on the ceramic block is no exception, as you can see on the left. For the Primescan, this seems to be less of an issue.

Global Accuracy

Up until a few years ago, intraoral scanners were still shown to have less full mouth accuracy when compared with PVS double impressions. Soon later, studies began to notice that it’s not just what you scan with, but how you scan that matters more. At CEREC Asia, we developed our Framework Scanning Method back in 2015 when our own research indicated that global accuracy with the Omnicam is heavily technique-sensitive. Our results showed that the difference between using Framework Scanning and scanning randomly can be over 200 microns.

With Primescan’s purported trueness and precision achivements, we were curious if a systematic method such as Framework Scanning is still needed. For our tests, we compared three pairs of data:

1. InEos X5 VS Omnicam (Framework)
2. InEos X5 VS Primescan (Framework)
3. InEos X5 VS Primescan (random path)

The first set of data is our baseline, the second set is the test group, the third set simulates a user new to using the intraoral scanner. Here are the results of the three comparisons.

The method shown in the above three images, called superimposition, overlays one model onto another and shows how much they differ using a color spectrum (legend on the right). The green regions are where the models match (within 50 microns), and thus are more accurate. There is also a histogram attached to the spectrum legend on the right showing the distribution of deviations. In short, the tighter and narrower the distribution, the more accurate the overall result.

Just from visual inspection of the preliminary results above, we can already see that the results for the Primescans are more accurate. Interestingly, the two Primescan results are very similar, so let’s look at some numbers (unit in microns):

The absolute average values in the table above indicates how much average deviation there is between the intraoral scans and the desktop scan. Lower absolute average means better accuracy (or more specifically, trueness). So within the scope of this simple study, we can draw some conclusions:

1. Primescan scans are cleaner and less noisy than those from the Omnicam.
2. Primescan is able to preserve more local details than the Omnicam.
3. Primescan is able to achieve better global trueness than the Omnicam even with Framework Scanning, but both are more than clinically acceptable results.
4. There is no significant difference in global accuracy between different methods of using Primescan.

It would seem that, if the results above are verified with a larger sample size, that Primescan is considerably less technique-sensitive than its predecessor. This is definitely good news as it may reduce the learning curve for new users. Out of curiosity, I ran a comparison between random scanning and Framework Scanning with the Primescan:

Since the above results comes from the same scanner twice (albeit with a different method), you can think of it as a very very rough precision estimation. More data is definitely required, but from our very rough tests, the Dentsply-Sirona claims of 30-ish microns of trueness and precision seems to hold up quite well.

For those of you who are interested, these average values are calculated by sampling between about 600,000 and 800,000 polygons per model.

Final Thoughts

First of all, apologies for going full nerd, but it sometimes happens when I see interesting tech, and the Primescan is certainly one of those times. So please accept my sincerest thank you for wading through all that and getting to this point!

The release of Primescan at this time, along with its complementary software, is intriguing because it signals Dentsply-Sirona’s push to capture a bigger DI (digital impression) market from other intraoral scanners. While in this article I focused almost entirely on the scanner, it is actually just the gateway into a whole slew of systems.

For dental professionals looking to purchase their first intraoral scanner, the ease of use and accuracy offers immediate short term benefits. At the same time, the A.I., the optional modular software, and great communities such as CERECDoctors.com are valuable assets for the longer term. For those of you in the Asian regions, CEREC Asia has some nice resources as well (disclaimer: I’m totally affiliated).

For current CEREC users, Primescan offers a fork in the road that we’re already traveling on. Assuming that the Omnicam will indeed get all the latest software updates, I feel that current users will be just as happy with either the Omnicam or the Primescan.

In reality, whether you purchase or upgrade to the Primescan will ultimately depend on two factors: price and long term plan. If all you need is something that replaces traditional impression and nothing else, then it really doesn’t matter whether you get the Primescan, the Omnicam, or any other major brand for that matter. But if you are planning a gradual conversion to the new digital workflow in restoratives, implantology, or orthodontics, then the DI-focused Primescan is a great first step into the CEREC ecosystem.

To be honest, nowadays you can do the same treatments with pretty much any system, but CEREC is still the most complete system with the most comprehensive learning resources. It all comes down to how much money and, perhaps more importantly, time you are willing to invest to enter the next stage of evolution in dentistry.

If you have any questions or comments, please let us know by leaving a message below.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post New Kid on the Block: Primescan and What It Means for Current and Potential Users appeared first on CEREC Digest.

In our workshops and seminars, we try to work with as large a diversity of ceramic blocks as we can, just as we do in our supporting clinic. Due to regional issues in Asia, there is some limitation on materials approved by government policies. Despite this, the available selection can still be quite daunting to the uninitiated. Naturally, one of the most popular questions that we hear is this:

“I don’t want to stockpile so many different kinds of blocks at my clinic. If you had to choose one, which one would it be?”

Imagine that you’re packing for some plein air painting in the Rockies. Which color would you pack? Green is probably a safe bet, if you are only going to paint leaves and bushes. What about the glaciers and the occasional maple tree? The answer of course, is that you wouldn’t bring just one color with you.

When we isolate our choice to an arbitrary parameter, it’s easy to lose sight of the overall perspective. For instance, material vendors love to talk about stuff like flexural strength, marginal integrity, and translucency. A quick check with google scholar will reveal that, of the three commonly used glass ceramics, feldspathics have substantially lower strength than those of lithium disilicates and zirconia-reinfored lithium silicates (ZLS). The following table lists some of the data, in MPa.

Source	Feldspar	Lithium Disilicate	ZLS
Manufacturer	154	360	370
Coldea et al, 2013	138	344
Vichi et al, 2013	103	-	-
Lauvahutanon, 2014	127	-	-
Stawarczyk, 2015	-	356
Lawson, 2016	-	377	451
Elsaka, 2016	-	348	444
Peteren, 2016	104	-	-
Goujat, 2017	-	210	-

So… we should never choose feldspar if we want long-lasting restorations, right? Or does each category of materials have its own advantages and disadvantages beyond just some numbers on paper? In the following clinical cases, I will focus on anterior restorations and discuss one very important factor in material selection (especially for single-visit restorations without cutback and layering): shade.

Howdy Neighbor

When restoring only a few units of dentition, you are at the mercy of the quality of their neighbors. For most patients that want their false teeth to remain as inconspicuous as possible, the shade and texture of the neighbors play a vital role in the material selection. In this first case, we used the Triluxe Forte, a feldspathic ceramic from VITA.

In my anterior workflow, choosing the material is preceded by systematic data collection and consultation with the in-house dental technician. The final decision is often based on numerous factors, such as: the base color and characterization of the target neighbors, the color of the abutments, the degree of axial reduction, and the depth of the bite.

For this particular patient, Triluxe Forte was an attractive choice primarily due to the shade gradient that matches very nicely with the laterals. This means that during external staining, the dental technician doesn’t have to deal with manipulating the base color, but can rather prioritize on characterization and texture.

Cool Colors

In this second case, we chose IPS e.max CAD, the de-facto lithium disilicate from Ivoclar Vivadent.

I’ve heard many times from our friends in the West that people there seem to be in love with e.max. Apparently its market share is something like 40%, which is crazy to me because I definitely don’t use e.max that often. For single units, I find that the initial saturation of color in e.max tend to be lacking for the typical Asian’s teeth, which is usually on the warmer side. For patients doing multiple anterior units, however, e.max does have that white-and-bright aesthetics, if they prefer.

For this patient, her #13 is also part of a bridge. According to recommended clinical indications of dental ceramics in ISO 6872, class III-B is defined as:

(Partially or) fully covered substructure for single-unit anterior or posterior prostheses and for three-unit prostheses not involving molar restoration adhesively or non-adhesively cemented.

The recommended flexural strength and fracture toughness for class III-B is 300 MPa and 2.0 Pa√m, respectively. IPS e.max meets both recommendations and has a block long enough for milling bridges.

A Head Start

In this last case, we chose the Celtra Duo, a zirconia-reinforced lithium silicate from Dentsply-Sirona.

For the most part, material choice isn’t mutually exclusive. From an optical perspective for the previous case, no one’s going to stop you if you insist on using feldspathic or ZLS with matching shades. There are, however, certain situations where you are just making it unnecessarily more difficult by choosing one material over the other.

For this patient whose natural teeth had high translucency, high chroma, and low value, starting with e.max might’ve been a long and arduous journey of staining hell. A Chinese proverb is particularly fitting here: “A good beginning is half the success”.

For me, choosing a material for anteriors is really like a puzzle that has no correct answers but definitely some wrong answers. The trick is to navigate the bad choices, and hopefully find an optimal canvas for the dental technician to start the painting.

For posteriors, on the other hand, strength requirements greatly limit the choices available. But that’s a whole other can of worms that I will save for another day.

The “One-Block” Solution

Clearly, not everybody has the time and resources to learn about every single ceramic and then choose the best combination for their patient demographic. What if I just want to start with one and work my way up, goddammit! For single-visit chairside restorations, it’s doable, but with a catch.

For your chosen ceramic, you need to know not just its strengths and indications but, even more importantly, its weaknesses and contraindications. Know when NOT to use your CAD/CAM system and fall back to traditional methods. If you plan on doing posteriors ceramics, learn the mechanical properties. If you are keen on venturing into the anterior region, do some lab tests and assess their optical properties. Know your material and tools inside out. The last thing we want is to over-promise to the patient and then under-deliver in aesthetics.

Material selection is such an expansive and interesting topic that our private study club has dedicated numerous discussions and paper-readings to it. If you are also interested, let us know your specific question and we will be glad to share our findings further.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post Is Choice a Burden or Freedom? <br/><div class='secondary-title'>A brief look at CAD/CAM material selection</div> appeared first on CEREC Digest.

Amidst the various special topics on digital dentistry, there was one clinical case that was of particular interest: the non-prep CAD/CAM ultrathin veneer.

Personally, I’m not too fond of these non-prep (or minimal-prep) principles because they either have very niche applications or require a balance of structural integrity. They also take a hell of a lot more work than typical veneers both before and after delivery, and frankly, I’m a pretty lazy guy.

Besides, everybody knows that milled ceramics have their limits, right?

Then on that fateful day, I saw this on my Facebook feed. It was a friendly jab from a master dentist who does some amazing restorations, albeit without CAD/CAM.

What have you done… As soon as I saw those simple words, my heart sank. Perhaps because I knew a certain dentist, who will remain anonymous (it’s Michael), who will not take these challenges lightly, jokes or not. Sure enough, the next day he volunteered me to take on the seemingly impossible task of replicating the same result but with CAD/CAM. In theory, I could’ve said no to the boss, but then I like having a job.

So with less than two months left to our annual event, we had to somehow figure out a way to create a milled ultra-thin veneer. But just how thin is ultra-thin?

“150 microns ought to be enough”

“…………………….”

If you’ve ever taken a close look at how ceramic milling works, you might be surprised that it works successfully at all; coarse diamonds strike violently at brittle glass, all at incredible speeds. But not all ceramics are created equal, so the first thing we needed to figure out is how thin each type of ceramic can be milled without chipping at the margins.

After bleeding a mountain of cash, we got a pretty good idea of what each type of ceramic is able to handle, and which of their corresponding marginal designs are optimal.

Our results have not yet gone through rigorous scientific validation, but of more than a dozen different ceramic blocks that we tested, we found that Enamic performed the most consistent. This was especially true for sub-200 micron restorations. It was time to put our theory to the test.

Not gonna lie, it was a big surprise to find that non-prep veneers are actually quite doable as a single-visit CEREC treatment option.

At our training center, one of our primary tasks is to standardize and optimize new workflows. So while this first case took an entire day due to trials and errors, we have already cut down the time needed by more than half in subsequent cases.

So what began as a challenge, became an obsession, became a team effort, and then eventual reality. On behalf of CEREC Asia, I would like to thank all the crazy dental professionals who contributed to this fun project.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post How Thin is Thin? <br/><div class='secondary-title'>The story of our single-visit ultrathin VITA ENAMIC® veneer challenge.</div> appeared first on CEREC Digest.

In this part of the world, we see a lot of class II cavities in our patients. So when most dentists begin their journey of CEREC chairside CAD/CAM, one of the first treatments that they try is the inlay restoration.

However, inlays are finicky by nature, and the slightest imperfections means saying goodbye to that snug fit. More often than not, the rookie digital dentist would either be unable to totally seat the restoration, or end up finding that dreaded gap along the margins with a dental probe.

Without the resources to troubleshoot these problems, it’s understandable why some would conclude that CEREC isn’t accurate enough, or that dental CAD/CAM is simply not yet mature.

Here’s the real problem: although inlay preparations are typically less aggressive, they are oftentimes the most technically demanding. This is because they are made up of both concave and convex angles, some of which needs to be smooth and round to prevent over-mill, while others need to be sharp to ensure proper ceramic thickness along the margins.

Not enough ceramic thickness means that the CAD/CAM block cannot withstand the forces of grinding or milling, and end up losing bits and pieces of itself in a process called chipping. This is bad news for everyone.

Furthermore, we also have to keep an eye on the amount of reduction; too little reduction compromises ceramic strength, while too much reduction increases risk of debonding and tooth sensitivity.

Say you’ve controlled for everything else, then the final step of ceramic selection is key in determining how smooth the margins can achieve after milling. In today’s discussion, we will be focusing on this so-called machinability of a resin-ceramic hybrid: the GC CERASMART.

Machinability Investigation

Machinability refers to how the ceramic responds to grinding (or machining), which invariably causes some degree of undesirable chipping. High machinability is preferable since it results in smoother margins on the ceramic.

While a lot of parameters play into how machinable something is, it basically boils down to one major factor: brittleness. An easy indicator of brittleness is the Young’s Modulus, so let’s take a look at the following table.

We already know that Enamic from VITA performs very well under machining, so with lower brittleness we can expect good results from CeraSmart. In the following section, we will compare the machinability of five different ceramic CAD/CAM blocks:

1. CeraSmart (GC)
2. Mark II (VITA)
3. Enamic (VITA)
4. Celtra Duo (Dentsply-Sirona)
5. Suprinity (VITA)

For each block we fabricated two different restorations: an inlay and an endo-crown. The thinnest portion of the inlay restoration occured near the distal-buccal line angle, so we were looking to see how much chipping had occured in this region. Regardless of material selection, all restorations used the same design in the CEREC software, and were milled under fine setting with brand new 12S burs.

For the try-in models, we used the highest resolution setting (0.025mm) on the Form2 3D printer from Formlabs. Here are some of the scanning electron microscope results for your viewing pleasure.

The difference between the resin-ceramic hybrids (CERASMART, ENAMIC) and other ceramics is fairly obvious. What we are looking at is the smoothness of the margin line. Jagged and irregular edges indicate that some ceramic content has been lost due to chipping.

In the above figure, we had intentionally made this region slightly thinner than usual to see how the margins would hold up for each ceramic. Looks like the resin-hybrids are still doing very well.

With three photos we can begin to see a pattern: resin-hybrids are doing much better than their feldspathic and lithium disilicate-based brethren, where the serration is especially pronounced in this particular image. Note that CERASMART seems to do slightly better than ENAMIC.

Under high magnification, we can see that resin-hybrids really do have smoother margins.

Same story here. So from the SEM photos, we can make a few observations:

1. In general, resin-ceramic hybrids (CERASMART, ENAMIC) have smoother margins
2. Specifically, CERASMART has comparable or smoother margins when compared with ENAMIC.
3. Even with shoulder margins, there are still chipping problems near some of the margins, with SUPRINITY being the worst offender.

Discussion

The rise of resin-ceramic hybrids in CAD/CAM dentistry was jump started by the drive for better material machinability. This was partially achieved through the addition of resin polymers, and our results concur with this logic.

So the question is, which hybrid is better? CERASMART has a slightly higher flexural strength than ENAMIC, but smaller Young’s Modulus than that of natural dentin. The assessment of advantages and disadvantage of these criteria is beyond the scope of this article, but if we are looking strictly at machinability, CERASMART seems to have a slight edge over its competition.

So what’s stopping us clinicians from choosing CERASMART for every patient? For one, its flexural strength and fracture toughness is not sufficient for bridges or posterior single crowns. Its translucency and light response limits its use in the aesthetic zones for certain patients. The biggest problem of resin-ceramic hybrids, however, is that they cannot be fired in the oven. This means that all external stains are essentially light cured and can wear off very quickly over time.

Conclusion

This investigation shows that not all ceramics respond the same way to grinding. With its added resin component, CERASMART seems to be able to produce smoother margins than most other ceramics. Its clinical application is still limited in indications, but the margin performance does give CERASMART a slight edge over its competition in the same category.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post Investigation: Margin Performance of CERASMART™ appeared first on CEREC Digest.

At IDS 2017, we compared intraoral scanners based on our hands-on impressions, as well as our interactions with sales representatives. During my research for writing the review article, one thing that piqued my curiosity was the method of image acquisition used by the Condor scanner. Software-driven was a buzzword that got thrown around at dental shows, but nobody was really able to provide me with a technical and satisfactory explanation as to what it is and how it is significant.

Until now.

Last month, I was offered the opportunity to interview one of the co-founders of Condor Scan, Professor François Duret, whose 1973 paper Emprinte Optique (Optical Impression) introduced the application of CAD/CAM concepts to the world of dentistry. Having published hundreds of papers related to this field, Dr. Duret was the first to describe a viable solution to chairside milling of restoratives. Decades before the internet became popularized, he envisioned a world where these virtual models could be sent from one doctor to the next for professional consultation. Reading his texts, it’s obvious that his ideas were really far ahead of their time, and was limited only by the technology available at the time.

Needless to say, I had equal parts of anticipation and anxiety while preparing for this interview. Although I have read and respected many of his scientific articles, I also didn’t exactly give the Condor scanner too much love in the review article. Fortunately, my worries proved to be completely unnecessary, and our discourse was both thoroughly enjoyable and educational. In this article, with Dr. Duret’s permission, I would like to share what I learned of the philosophy and technology behind Condor intraoral scanner.

Diagnostic First

Whereas most dentists, myself included, look at intraoral scanners as a replacement for the traditional impression tray, Dr. Duret sees the intraoral scanner as a diagnostic tool first and foremost. For him, the value of being able to acquire a 3D representation of the oral condition is the preservation of information and its utility in patient communication. This does not exclude the application in milled restoratives, which is vital to the economy of intraoral scanners. But, true to his original vision in the 70s and 80s, Dr. Duret believes that the connectivity among dentists and dental technicians is most important. Furthermore, the possibility of longitudinal patient history (as we saw from 3Shape), as well as the connection with CBCT means even more diagnostic potential.

For this reason, Dr. Duret is not overly concerned with the accuracy of the scanner as long as it is good enough. To him, an improvement of microns makes little difference as far as diagnostics are concerned. Color, on the other hand, is then incredibly important.

Hardware- vs Software-Driven

Before we get into why color is important, we need to first talk about how Condor is different from other scanners. At the moment of this writing, most intraoral scanners derive the 3D model of the oral cavity by manipulating and measuring the deformation of projected or structural light. In the 1970s, one of the earliest method of doing this was Moiré topography, which takes advantage of interference of projected dark lines on a textured surface and, combined with mathematical transformations, generates the distance data needed for 3D models.

A more modern approach is the confocal microscopy method. Essentially, the camera captures only the parts of the image that are in focus at a predetermined focal length. By rapidly shifting the focal plane, a series of images can be put together to form a 3D model. (Fig) If it sounds complicated, that’s because it is. And, according to Dr. Duret, quite a few things can go wrong in the setup: the lens, laser, quality of light, light transmission, mirrors, and mechanisms to move the mirrors, just to name a few. Now imagine having to cram all that technology into the size of a handheld device AND trying to manage an accuracy that is measured in microns. This marvelous feat of engineering necessitates complex hardware, which are ultimately responsible for the high cost and large size of intraoral scanners.

The basic idea behind the Condor scanner is to offload the majority of this complexity into the software, utilizing a concept called stereophotogrammetry. This technique is actually already fairly mature, and is what enables Google Maps to generate 3D topography. Using complex math algorithms, photos of an object taken at different angles can be converted into three dimensions. By letting the software do all the work, the scanner can be made drastically more simple than other intraoral scanners. 

According to Condor, the technology that dentists are purchasing, in a way, is mostly the software rather than the hardware. While hardware gradually becomes outdated over time, software can be easily updated every few months for fixes and improvements. In addition, patching in new features and functions is also a possibility. In the long run, if the resolution of the scanner head can no longer satisfy the demands of the software, it is also less expensive to replace the hardware due to its simplicity.

No Color, No Condor

Over the last few years, the evolution from gray-scale to colored digital impressions may seem like a reasonable and self-evident progression, but what we saw from IDS this year appeared to suggest otherwise. Out of the eleven scanners we reviewed, four of them did not scan in color. 3Shape also recently released the colorless version  of its Trios called Trios Mono, so clearly there is market demand to sacrifice color for a better price tag. In this camp, the prevailing argument is that color information has always been absent on stone models, and so it is not essential.

Trying to formulate a diagnosis using stone models is of course possible for, say, occlusal interferences. But for diseases and soft tissue disorders, color can become quite necessary. For the Condor scanner, color is not only very important, it is vital to the scanning process. The software uses color information in the photos to help determine reference points and calculate topographical features. Because the color is acquired directly, it’s primacy also allows the intraoral scanner to produce accurate colors, according to Dr. Duret. This is very different from the likes of other scanners that uses a separate, secondary camera to capture and map the color texture information onto the generated 3D model. For Condor, color is not just an afterthought, it’s part of what makes everything work.

“It’s difficult to get the same accuracy as the [best scanners] because there is no projection of light, but with less than 50 microns [of accuracy] it is enough… while you give the dentist the truest reproduction of color.” Dr. Duret said during the interview. Then he added, “The difference between 20-50 microns is peanuts.”

This perspective is perhaps less sought after, especially in contrast with the scan-and-mill utility that most dentists are familiar with, and for good reason. Intraoral scanners, for the most part, are an investment from which returns are expected. Compared with direct monetary benefits from milling your own restorations, diagnostics provide passive benefits that are less tangible and more difficult to quantify. Everyday when I use the CEREC with my remaining arm and leg, I’m deeply aware of the burden of dental economics.

So with a massive price advantage over its competitors, how has the diagnostic-first principle of the software-driven Condor fared in reality?

Theory, in Practice

As a new kid on the block, the Condor scanner made waves last year with the unveiling of its small scanner size and realistic colors. Both of these features actually impressed us at IDS, as well as its cleaner-looking reproduction of the oral cavity. But, as I wrote in the review article, the biggest issue with the Condor was its slow speed. Unfortunately for them, the disparity was especially telling because I used the two fastest scanners as benchmark.

With a software-driven framework, it is conceivable that the overall scanning process will improve with smarter algorithms and more powerful computer hardware. As long as the scanner is able to take clear photos, the accuracy limit of the 3D models is theoretically the amount of information contained within each pixel.

The keyword, though, is theoretically, and whether your scanner will actually grow with the technology remains to be proven. Though to be fair, the emphasis on software solutions has seen its fair share of successes, from arithmetic calculators to the Tesla automobiles. So at least Dr. Duret team at Condor is standing on the right side of history.

Of the Past and the Future

One of my favourite moments of the interview was when Dr. Duret was cheerfully describing how CADCAM used to be done, when he first started all those years ago. The painstaking model reconstruction, the struggle to generate 3D surfaces due to inadequate computing power, and the anxiety of failing the first live demonstration after years of practice and development. There is no hiding of his love for dental technology and CAD/CAM, or, as he fondly called it, his “baby”.

As a final question, I asked the good professor what he hopes to see for the future of digital dentistry, and whether the current state has met or exceeded his expectations back when he introduced these concepts all those decades ago. Here is his list of wishes for what’s to come:

• Lowering of price [of scanners, CAD software, and CAM hardware]
• Free selection of scanners and milling devices (As a CEREC user, touché)
• Standard communication between different software
• Very easy to use and manipulate

And as for the current state of digital dentistry, I think there’s no better display of devotion and passion than with Professor Duret’s own words:

“I started again my research because I don’t agree with the movement of the scanner we had five years ago. This is why I started again and rejoined the arena after retirement. I was very disappointed that they don’t take care of my baby. I am a dentist and my priority is as a dentist, and their priority is engineering and milling. Not dentist. This is why I was very aggressive in the last few years because this is the end of my life, and I refuse to see people only make money and not introduce a digital life.”

A Special Thanks

To Shane De Vreese for graciously setting up this interview and, of course, to Professor François Duret himself for such a fun and lovely conversation.

References

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post A Unique Approach to Intraoral Scanning <br/><div class='secondary-title'>Notes from an interview with Dr. François Duret</div> appeared first on CEREC Digest.

Getting a reliable full-mouth scan has always been an issue for intraoral scanners. Unlike desktop scanners, intraoral scanners have much smaller fields of view, which means a drastic increase in both the number and complexity of image-stitching operations. In such a case, the quality of the images become paramount, and short of changes in hardware, the primary control for the user is the method with which the scanners are manipulated. Therefore, proper usage of the intraoral scanner is very important. Naturally, the next question becomes: what is “proper”?

A recent report from CERECDoctors.com approached this question from a bite-registration angle. The main question they asked was, essentially:

Does the method of scanning the full-arch affect digital bite-registration?

So what method are they talking about, and how does digital bite-registration work? In a typical intraoral scanning procedure, we perform three basic scans:

1. Lower arch scan
2. Upper arch scan
3. Buccal scan

To draw a parallel to traditional workflow, #1 and #2 would be the upper and lower stone models, while #3 is the bite registration. Whereas the traditional bite registration material is a negative impression, the digital buccal scan is a positive reproduction. By correlating the buccal scan with both the upper and lower scans, the three dimensional relationship between the latter two can be established.

You might be thinking: what if the buccal scan doesn’t exactly match the other two scans? Actually, an exact match is technically impossible due to differences in boundaries, soft tissue, and other inconsistencies. This means that the computer has to perform some averaging calculations and decide on a best-match scenario. For quadrants and other smaller scans, the software generally does a decent job. However, as the length of the scan increases, things get complicated.

Stitching

Imagine using a 15-cm ruler to draw a straight line that is 5 meters long. No matter how meticulous you draw each segment, the final line will not be perfectly straight. If the line is now 50 meters long, it’s reasonable to assume a larger deviation will occur, since the errors accumulate over each 15-centimeter iteration. Scanning a full-arch is very similar. As you move the scanner head across a surface, individual images are stitched together rapidly to form the final model. With longer scanning areas, the errors ultimately add up to cause more and more deformations.

So let’s go back to our upper- and lower-arch scans. If they are sufficiently deformed, then it is not a surprise that software has a hard time superimposing a third, buccal scan and trying to figure out what the “best-fit” is. This deformation is the crux of the issue in the report from CERECDoctors, where they investigated the reasoning behind unreliable bite registration in full-mouth scans.

Results from the study

The first observation that the report made was that where you scan the buccal bite matters. Given the same patient (or typodont), if you scan the bite registration on the right side, the software gives you heavier occlusion on the right; similarly, a left buccal scan gives heavy occlusion on the left. This is obviously not ideal, and given what we know about deformations now, how do we get around this issue?

In the previous example, the full-mouth model was scanned in an arbitrary method with no predetermined pathway. From our experience at our training center, most first-time users naturally and understandably subscribe to this sort of random movement of the scanner head. Unfortunately, this has been shown to result in more stitching errors and therefore more deformation.

In the CERECDoctors report, they recommend a different method of scanning called a Linear Scan. The idea was adopted from the CEREC Ortho software, which was designed specifically for orthodontic full-mouth scanning.

Basically, in Linear Scanning the full-arch is scanned in three continuous and linear scans, followed by several rolling scans that “tie” the linear scans together. With no backtracking during the linear scans, the software seems to be able to produce a model with minimal deformation. Therefore, it no longer matters where the buccal scan is, the final occlusion of the full-arch models is the same (see figure below).

Putting numbers to the deformation

This deformation problem is not new, and at the CEREC Asia training facility we have been advocating the Framework Scan method (our version of the Linear Scan) for more than a year. In order to prove to ourselves that doing a Framework Scan is actually beneficial, we decided to perform a small study to quantify the deformation.

One way to simplify the calculation of full-arch deformation is by taking the linear error between two reference points. The assumption here is that with greater error, more deformation has occurred. Therefore, by comparing different methods of scanning, we can determine if there are significant discrepancies in accuracy.

Method

First we fixed an easily-discernible physical marker on a typodont in the 18 and 28 location, and made a stone reproduction so that there are no movable parts. Then we tested four different methods of using the CEREC Omnicam, and compared their results against a desktop scanner (InEos X5). To do this, we use a computer software to measure the linear distance between our markers on each model (see figure below), and then calculate the differences between them.

Results

Here are the results to our test:

So the five scanning methods that we tested were:

1. Desktop Scanner: InEos X5
2. IOS: Following the CEREC Ortho guided scanning procedure
3. IOS: Using a method adopted from CEREC Ortho that we call Framework Scan (or Linear Scan from CERECDoctors.com)
4. IOS: Following recommended scanning guidelines from Dentsply Sirona in 2014
5. IOS: Following an updated 2016 guideline from Dentsply Sirona

In short, our results show that CEREC Ortho, Framework Scans and the InEos X5 desktop scanner show similar cross-arch stability. Since it is rather difficult to categorize an arbitrary scanning method due to its randomness, we decided to compare to the official guidelines from Dentsply-Sirona instead. Even there, statistically significant differences can be observed. Though it should be noted that these guidelines were not intended for full-arch scanning.

Conclusion

• Using the Framework Scan method can produce cross-arch stability comparable to the InEos X5 desktop scanner.
• Both Framework Scanning and CEREC Ortho produces better cross-arch stability than the official guidelines, which were not intended for full-arch scanning.
• For full-arch scanning, Framework Scanning (CERECDoctor.com’s Linear Scanning) can produce more reliable results.

In summary, while the quality of the tool matters, it’s equally important to use it properly. If you have any questions, feel free to comment below, or join our discussion over at the Facebook group. We are constantly looking for ways to improve, and would love to hear about your personal experience with any intraoral scanner regarding full-arch accuracy.

Anyway… what’s up with the 2016 guidelines getting its ass whooped it by an older guideline?

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post Not All Scans Are Equal <br/><div class='secondary-title'>Full-arch scanning with CEREC Omnicam</div> appeared first on CEREC Digest.

So this 90-year-old male had a minor chewing mishap, and his tooth #21 (with previous endodontic treatment) snapped off quite cleanly as shown in the following photo.

The patient was over 90 years old and completely uninterested in fixing his multiple non-carious cervical lesions. After some back and forth, my final treatment plan was to simply restore #21.

The only remaining tooth structure was on the palatal side, but the patient also had a very deep bite, so really not the best combination of circumstances. After a precarious act of balancing occlusal clearance and tooth structure removal, the abutment was ready for gingival retraction and scanning.

There was a lot of design flexibility for this restoration, thanks to the severity and angle of fracture. With sufficient space to play around with, a physical indentation near the cervical region was possible to mimic the cervical lesion. We chose the Triluxe Forte due to the large shade gradient between cervical and incisal regions.

After cementation, I noticed that the cervical areas on the natural teeth are slightly less reflective, so I de-glazed the cervical regions with a twist polisher. Unfortunately, the instrument slipped a bit and lacerated the gingiva. My bad.

Luckily, things seemed to have healed over decently after a couple of weeks.

Remarks

Of course, this wouldn’t have been possible without Sharon, one of our wonderful in-house dental technicians. The reference shade used for this crown was 4R2.5, and with such an unusual color, we were fairly fortunate to get the color very close in one try; for a case like this, I typically set aside enough chair time for two attempts. The total chair time for this patient is about 90 minutes, not including endodontic re-treatment.

We are still getting the hang of CEREC! So while this case may not be perfect, it was definitely an interesting learning experience.

Hsuan

Hsuan is a lecturer at CEREC Asia Training Facility. He is from Vancouver, Canada, and is a big fan of prosthodontics and profanity.

toothfaerie.club/

The post Fun with Staining and Glazing <br/><div class='secondary-title'>CDT: 周星妤 (Sharon)</div> appeared first on CEREC Digest.