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Makers of implant bars and bridges speak about accuracy

There is a lot of talk in the market about 3D dental scanner accuracy – and for a good reason. Accuracy matters – especially to those producing precision-demanding indications such as implant bars and bridges. We spoke with managers at two CAD/CAM production centers. Both companies manufacture dental restorations based on designs created with 3Shapes CAD software and dental lab scanners.

Here are their stories:

Avinent, Spain

Scan accuracy saves us loads of time 

AVINENT/Core 3D designs manufactures, and markets products for the dental industry –specializing in implantology solutions. AVINENT/Core 3D is recognized for its expertise in the use of CAD-CAM technologies. The company produces between 35 to 40 advanced implant bars every day, and they, therefore, depend on high accuracy equipment. We met Mr. Xavier Camí Gorriz, Innovation and Business Development Manager, Avinent/Core 3D Group

How important is accuracy for your business?
“High-quality results are imperative to Avinent/Core 3Ds business and are the foundation of our customer promise. When we started working with CAD/CAM, we were challenged by too many implant bar cases in which the CAD design did not precisely match up with the original gypsum model.”

So how did you ensure accuracy?
“We developed a way to gauge accuracy by measuring the true implant positions in the model using a probe scanner and when needed, we adjusted the CAD design according to the probe scan. Our milling center then manufactured the restoration using the amended CAD design file.”

Did this solve all accuracy issues?
“Well -while the procedure solved our immediate problems because it ensured accuracy, it also had significant drawbacks. Probe scanning and readjustment introduced an extra time-consuming step to the manufacturing process, which was also required resources, including logistics, around the need to receive and handle gypsum models with every case.” 

Have you found a better way?
“A better way presented itself. From 2011, many of our lab clients, who were working with implant bars and bridges, invested in 3Shapes D800 scanner – mainly due to its 5.0 MP cameras and accuracy specs. Soon after, Avinent gradually became aware that the original designs they received based on scans from the D800 were always accurate according to the probe scan results.”

How did this discovery affect your business?
“It simply made our production turnaround faster for many cases. We continued testing with the probe scanner for a while, but, as there never was a need to apply adjustments, we opted to skip the whole step because we could completely rely on CAD designs originating from the 3Shape scanners.  Today, all cases from labs using the D800 save us loads of time, and the more of our customers who are using 3Shapes high-end scanners, the more time we will save on implant bars and bridges cases. Our customers win too – they don't need to send us their gypsum models anymore, and they get the restoration back faster.”

R+K CAD/CAM Technology, Germany

Accuracy matters – all along the workflow

R+K produces and markets dental manufacturing solutions (ORGANICAL System), and provides restoration manufacturing services from their milling center in Berlin, Germany. Implant bars and bridges make up a large part of their service portfolio, and, therefore, they have continuously pursued the most accurate methods available. In the process, R+K have accumulated valuable knowledge about accuracy from scan to production, including key challenges and solutions. We spoke with Marko Bähr, MDT (Master Dental Technician) and CAD/CAM specialist at R+K.

How do manual and digital methods compare in terms of accuracy?
“R+K, together with worldwide partners, produces hundreds of implant bars and bridges every month, including bars with up to 8 implants and large anatomically reduced bridges with up to 16 teeth. The digital methods allow us to achieve such high throughput. But speed is not the only reason we work digitally. These restorations require accurate methods in order to ensure that the bar or bridge fits perfectly with the implant positions. And, in our experience, the digital way lets us be more accurate than by using manual techniques.”

What factors in your workflows are most critical for accuracy?
“Basically all factors along the workflow chain can influence the accuracy of the end result. These include impression-taking at the clinic, the scanner that captures the model, scan flags, design parameters, materials, milling strategies, and the quality of the milling machines. For optimal results, accuracy must be maintained during all stages. Naturally, 3D scanning is among the more critical steps because it is here that we go from a physical format to the digital format – and this transformation must be completely reliable as it sets the scene for a design and later manufacturing.”  

Are the tools you use accurate?
We use 3Shape D800 scanners and scan flags to scan the models and capture implant positions. The high resolution 5 MP cameras and well-known 3Shape scan quality provide good detail, and this facilitates accurate processing in the remaining workflow steps. For production, we use our own R+K milling machines (ORGANICAL Multi), and we build them to meet the highest standards for accuracy. In the end, we apply 3Shapes Convince software to control the final results before sending the restoration to the dentist.”

Do you have any plans for changes to your methods or equipment in the near future? 
Looking ahead, R+K will soon be producing implant bars and bridges in a new and more elastic Zirconium material (Panasonic NANO Zr). We will also boost our scanner arsenal with the new 3Shape D900 scanner which supports 4 x 5MP cameras. According to its specs, it's even faster than its D800 predecessor – yet without compromising accuracy.”

We would like to thank both Mr. Xavier Camí Gorriz from AVINENT/Core 3D and Marko Bähr from R&K CAD/CAM Technology for making themselves available for the above interviews. In coming newsletters, we will look closer at scanner accuracy – to shed light on this important topic in terms of both user requirements and the technologies applied. Stay tuned for.