Dental Asia March/April 2019

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In Depth With 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). Table 1: Comparison of full-arch precision by Imburgia, 2017. A Totally Non-Scientific Accuracy Test Local Accuracy: Resolution As I mentioned earlier, local accuracy is about how much surface detail can be accurately reproduced. To start off, here is a close-up of two scans by the Omnicam (left), and the Primescan (right). Comparison of surface texture 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. Comparison of mesh distribution The STL file sizes are 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 denser 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 signalto-noise ratio allows the Primescan to preserve more detail. Local Accuracy: Sharp Edges A used emax block for the edge test 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. Comparison of details near the edges Comparison of unreflective surfaces If you’ve ever used an Omnicam, you’ll know that it often has trouble with dark spots, like stains on the enamel, 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 achievements, we were curious if a systematic method such as Framework Scanning would still be needed. For our tests, we compared three pairs of data: - InEos X5 VS Omnicam (Framework) - InEos X5 VS Primescan (Framework) - InEos X5 VS Primescan (random path) 78 DENTAL ASIA MARCH / APRIL 2019
In Depth With 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. See the results of the three comparisons. Primescan results are very similar, so let’s look at some numbers (unit in microns): Positive Avg Negative Avg Absolute Avg Std Deviation Omnicam (F) 48.0 -43.9 46.0 59.0 Primescan (F) 26.6 -21.8 24.2 41.1 Primescan (R) 26.2 -24.1 25.2 39.3 Since the above results come from the same scanner twice (albeit with a different method), you can think of it as a 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 seem to hold up quite well. The method shown in the above three images, called superimposition, overlays one model onto another and shows how much they differ using a colour 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 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: • Primescan scans are cleaner and less noisy than those from the Omnicam. • Primescan is able to preserve more local details than the Omnicam. • Primescan is able to achieve better global trueness than the Omnicam even with Framework Scanning, but both are more than clinically acceptable results. • 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 techniquesensitive 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: Positive Avg Random vs Framework Negative Avg 29.1 Absolute Avg -33.3 31.2 Std Deviation 45.1 For those of you who are interested, these average values are calculated by sampling between approximately 600,000 and 800,000 polygons per model. Final Thoughts The release of Primescan at this time, along with its complementary software, is intriguing as it signals Dentsply-Sirona’s push to capture a bigger DI (digital impression) market from other intraoral scanners. 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 and CEREC Asia are valuable assets for the longer term. For current CEREC users, Primescan offers an interesting alternative. But assuming that the Omnicam will indeed still get all the latest software updates, current users will be just as satisfied with either the Omnicam or the Primescan. In reality, whether practitioners purchase or upgrade to the Primescan will ultimately depend on two factors: price and long-term plan. If a practice needs something that replaces traditional impression and nothing else, it really doesn’t matter whether it opts to get the Primescan, the Omnicam, or any other major brand for that matter. But for practices that aim to undergo 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. DA MARCH / APRIL 2019 DENTAL ASIA 79
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CONTENTS MARCH / APRIL 2019 18 24 2
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First Words The New Age of Digitali
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Dental Updates New VOCO Prophylaxis
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Dental Updates AACD Welcomes 2019 C
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Periodontal Disease Bacteria Linked
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Dental Updates Henry Schein One Acq
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Under the Spotlight 18 DENTAL ASIA
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Under the Spotlight It is easy for
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Word of Mouth by Dr. Christoper Ho
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CELEBRATING DIGITAL TRANSFORMATION
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Dental Profile achieve very good re
Page 31 and 32: Dental Profile TAKING DIGITAL IMPRE
Page 33 and 34: Dental Profile The high-precision S
Page 35 and 36: Dental Profile MARCH / APRIL 2019 D
Page 37 and 38: Clinical Feature The importance of
Page 39 and 40: Fig. 8: X-ray after extraction show
Page 42 and 43: Clinical Feature Glass Ionomer Seal
Page 44 and 45: Clinical Feature Fig. 1.1: An erupt
Page 46 and 47: Clinical Feature 7 TH GENERATION AD
Page 48 and 49: Clinical Feature 1. Decay is noted
Page 50 and 51: User Report CENTION N: REDEFINING D
Page 53 and 54: User Report Amalgam GIC Cention N P
Page 56: User Report Fig. 15: Teeth 46 and 4
Page 59 and 60: User Report initial drilling channe
Page 61 and 62: User Report Fig. 16: Postoperative
Page 64 and 65: Behind the Scenes REPLACEMENT OF EX
Page 66 and 67: Behind the Scenes angles due to the
Page 68 and 69: Behind the Scenes and silanated for
Page 70 and 71: Behind the Scenes A JOURNEY THROUGH
Page 72 and 73: Behind the Scenes Fig. 11 Fig. 15 r
Page 74 and 75: Behind the Scenes The overall aesth
Page 77 and 78: In Depth With Fig. 1: Primescan - t
Page 79: In Depth With The blue light used b
Page 85 and 86: In Depth With Extending Dental Oper
Page 87 and 88: In Depth With combines the cutting-
Page 89 and 90: Product Highlight BRAVIA ® XL Spec
Page 91 and 92: Product Highlight COLTENE Unveils t
Page 93 and 94: Product Highlight 3Shape launches T
Page 96 and 97: Show Preview 9 th -12 th June 2019
Page 98 and 99: Giving Back to Society February is
Page 102: Advertisers’ Index Advertisers Pa
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Dental Asia March/April 2019

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