How do 3D Printed Dentures Stack up when Compared to Milled and Injection Molded Dentures?

Korean medical researchers have been looking into the differences in quality and accuracy of several different modern ways to make dentures, with a focus on whether there is really any significant difference between any of the techniques. The key in producing dentures is in creating a snug fit between the base and the patient’s mucosal tissue, with both deformation and shrinkage being a concern because they can affect nearly every aspect of the wearer’s experience.

It’s no secret that no matter how good dentures are, challenges remain for everyone, whether they are the technician producing them or the patient wearing them. And you may not have dentures, but most likely you have seen someone else struggling with them. Manufacturers are constantly trying to improve on areas of discomfort and ill fit, and in the last 20 years, digitalization has played a major role in improving on accuracy in production.

“When manufacturing a complete denture using digital workflow, the process begins with digital scanning of the edentulous arch, including challenging areas for the intraoral scanner device to scan, which are movable areas such as non-keratinized tissue and smooth surfaces covered with saliva,” state the authors.

Once the impression is digitized, the denture is created in CAD and then it can be milled, or a 3D printed prototype can be created. The base is the most critical area, and results are centered around accuracy—making this a topic of great research (and development) over the years, and one that the authors mention has been greatly insufficient in regarding 3D printed prototypes.

Schematic illustration of denture base fabrication.

In this study, thirty different denture bases (ten for three groups) were examined. For the injection molding group, wax block was milled, based on the .stl file, with the base created via injection and PMMA resin. The milling group bases were made on a five-axis milling machine, and the rapid prototyping group of dentures were made on a DLP Bio3D 3D printer, cleaned in isopropyl alcohol for five minutes and then hydrated for 24 hours.

 “There was no significant difference in the overall deformation in the horizontal direction among the three methods through comparison of distances between the 4 notches of the ridge,” concluded the researchers. “Comparison of fit accuracy between the cast and the maxillary complete denture base was evaluated on the 2nd upper premolar and the 2nd upper molar crossing the midpalatal suture, showing relatively high deformation in the conventional method due to polymerization shrinkage and the internal stress.”

“The mean value of discrepancies was the lowest in the RP method, followed by that in the milling method and the injection molding method. The injection molding method had significantly lower fit accuracy than the other two CAD/CAM methods at two points. The degree of resolution was evaluated by measuring the vertical distance between the highest point and the lowest point in the palatine rugae area because of the complexity of the architecture. The injection molding method had significantly higher resolution than the milling method and the RP method.”

If you are just learning about 3D printing, you will probably be surprised to find out what a role it has played in the world of dentistry and orthodontics, and reconstruction in both areas. If you are well apprised of the miracles of 3D printing, you are probably still shaking your head in wonder over how it has taken off in the dental market, especially allowing for a variety of different dentures and molds to be made, along with new and improved 3D printers coming to market regularly.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Comparing accuracy of denture bases fabricated by injection molding, CAD/CAM milling, and rapid prototyping method’]

Points crossing the anterior alveolar ridge and posterior alveolar ridges (right: a, left: b) and points on posterior alveolar ridge from 15 mm distance parallel to the midpalatal suture from right and left hamular notches (right: c, left: d).

Injection molding method process. (A) Denture base fabricated from wax block by milling, (B) Investment of denture base, (C) Fabricated denture base.

Made in Space: Proving Further 3D Printing & Robotics Capabilities with Archinaut System

 

 

 

We hear a lot of talk these days from global aerospace players about how 3D printing and robotics will further space travel, assist in further exploration of the Moon, colonize Mars, and employ futuristic plans that sound like they will allow many of us to live out fantasies not unlike those we’ve enjoyed during sci-fi movies (just leave out the apocalyptic darkness and terrifying space monsters please).

Now, Made in Space is continuing to live up to their name in regards to technical functionality in space, having just reached another achievement with Archinaut, part of an ongoing collaboration with NASA to further self-sustainability in space through construction of satellites and even entire spacecraft while away from Earth. In connection with their NASA Tipping Point contract, they have further proven AM and robotics capabilities in testing, in cooperation with the Archinaut Technology Development Project (ATDP), funded by NASA’s Space Technology Mission Directorate (STMD).

The system was evaluated in thermal vacuum (TVAC) testing last fall in Redondo Beach, California at Northrop Grumman’s Space Park facility, during simulation of thermal and pressure environment of a satellite in Low Earth Orbit (LEO). This is just one more critical step toward making the Archinaut system ready for manufacturing parts in space, using dynamic programs like the PowerKit system, able to deploy a 2kW power system on a 150 kg ESPA-class satellite—exhibiting power five times that of current systems. Other deployment systems include an antenna that can perform major duties like exploring space, along with managing telecommunications and remote sensing.

“This technology will contribute to a more sophisticated low earth economy and lay the groundwork for more advanced commercial utilization of space,” added Rush.

MIS has even set a record with their extended additive manufacturing technology (ESAMM), capable of making structures longer than even the machine itself, with a Guinness World Record set at 37.7 meters long. In testing, MIS was also able to demonstration successful operation of ESAMM in a thermal vacuum chamber.

Led by Made in Space, other partners such as Northrop Grumman are providing integral development to the project also, mainly in systems integration. Oceaneering Space Systems was responsible for the robotic arm which will be so integral to the creation of sizeable structures built in space, along performing necessary upgrades. The robotics system can also be made responsible for doing repairs, along with small sat integration when payload retrievals and installations are necessary in space. During testing, the MIS team was able to show off the functionality of features like the following:

  • Autonomous reversible connection
  • Joining techniques of 3D printed parts
  • Nodes and trusses for robotic arm
  • End effector for assembly operations

“We are very proud of our team for achieving this critical proof point that ultimately lines us up for operational missions with customers in both government and commercial sectors,” said Andrew Rush, President & CEO of Made in Space. “We look forward to the next steps of preparing Archinaut-enabled missions for flight.”

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source /Images: Made in Space press release]

Made in Space delivered the first 3D printer to the International Space Station.

SHINING 3D debuts Aoralscan 3D scanner at IDS 2019

The first day of the International Dental Show (IDS) 2019 in Cologne, Germany continued to welcome new digital dentistry innovations. SHINING 3D, a Hangzhou-headquartered 3D scanner and printer manufacturer, has debuted its intraoral (within the mouth) 3D scanner, the Aoralscan. Upon its launch, Oscar Meza, VP of Global Sales of SHINING 3D stated: “We offer a comprehensive digital dental […]

Interview With Honeywell’s Dave Dietrich on Implementing Additive Manufacturing for Businesses

Dave Dietrich is an Engineering Fellow at Honeywell Aerospace. There he was involved with the systems and defense firm’s 3D printing effort. His job is to guide, help and train his fellow engineers in adopting 3D printing for aerospace in the firm. He advocates for a DfAM approach whereby one identifies and designs for the advantages of Additive Manufacturing from the start of a design and development project and indeed this is also the approach that we favor. In previous roles he was an adjunct professor Engineering Management and worked at Boeing as a materials process and physics engineer and later as an Oak Ridge National Laboratory fellow on 3D printing metals. He was also the metal 3D printing technical lead at Boeing and initiated Boeing’s internal metal 3D printing training program.

Dave has now written a book, Additive Manufacturing Change Management: Best Practices. He told us that, “The target audience of this book would be managers/project managers/executives who may not know how or why their company should implement AM.” He also believes that “barriers holding AM back from becoming a widely adopted manufacturing technology within industry has just as much, if not more, to do with business and organizational challenges than technical challenges.” This is a very timely book that could help a lot of firms evaluate and adopt 3D printing in their organization. We asked Dave a number of questions to learn more.

Often there is a lot of institutional resistance to adopting AM in industry. How does one overcome this problem? 

As change agents for AM within industry, my co-authors and I have each had common experiences with respect to institutional resistance. From our experience, it seems that there are deeper underlying currents that have more to do with resistance to changing the company culture than AM technology itself. AM is disruptive. It challenges every notion of typical manufacturing practices, design practices, quality inspection practices, and generally accepted notions of supply chain behavior. As such, overcoming this resistance it has more to do with understanding change management philosophy than breaking through specific AM technical hurdles. Luckily, there’s lot of written documentation in the field of industrial change management, namely, Lean Manufacturing and Six Sigma quality systems. Our book adapts lessons learned from Lean and Six Sigma fields and uses some of those tools when installing AM cultural changes.

For some reason, if customers select a test part for 3D printing its always the wrong one, why is this? 

Often, it is a lack of understanding of the technology. Perhaps they didn’t select the correct process, material, or post-processing requirements for the part, or perhaps the engineer involved with the part didn’t think about the ramifications of poor surface finish. Alternatively, perhaps that specific test part was design for a conventional technology and not adapted to AM capabilities at all. There could be many reasons. About 5 years ago, someone once told me that AM is the wild west of manufacturing. I’d like to hope it is becoming a little more civilized (perhaps more Sheriffs now?), but there is still an enormous education gap regarding the technology capability. I also blame marketing pieces from competing companies designed to highlight the enormous benefits of AM. Of course, these media publications don’t highlight the many pitfalls the company went through to gain a good part. Based on this media blitz, competing companies will often head off to build their own AM test parts in an effort to stay competitive without management understanding the true pitfalls of the technology. Our book directly addresses these challenges.

Metal printing is touted as the future of manufacturing. Meanwhile, it consists of a guy with a brush and a vacuum cleaner cleaning off powder while another takes a circular saw to saw off parts. How do you reconcile that? 

Again, I think it gets down to the overmarketing of the technology. AM itself is not a product. AM itself is not an end to a solution. AM is a tool in the engineering toolbox to solve manufacturing problems. Albeit, an incredibly disruptive one. It also just so happens to be the “most shiny” tool right now. But beware, when the engineer reaches for that tool, they better know how to use it properly! There will always be heat treatments, cutters, hot isostatic pressing, and yes, even folks with brushes and vacuums. Pieces of this will evolve to automation over time, but often over marketing can lead to misperceptions of the technology, which leads to the confounding conclusions you point out in your question.

QA is still a huge problem in 3D Printing, what are some best practices for this?

Yes, there is an inherent conflict between highly optimized AM structures that are beautifully designed and practical inspection and machining of these parts. For metallic AM parts, CT inspection has always been an expensive, but not always a practical solution to this problem. White light scanning is also used to a semi-effective result. Dye penetrant inspection of machined surfaces, in-situ build process monitoring, and other traditional inspection techniques have been used somewhat effectively. There are also challenges on the software side comparing what has been printed, in terms of dimensional conformance, to true CAD definition. I think this is an area that needs more development in the future as AM becomes more production hardened.

What needs to be improved on the 3D printers themselves? 

Recently, I believe we are beginning to see a more hyper-competitive landscape for the metal AM powder bed fusion technology. At Formnext, each year, I see exponential growth in the number of new machine manufacturer entrants into AM. I think this hyper competition will create faster, larger machines with more lasers. This seems like an incremental step, not necessarily a leap frog type of improvement. I’d like to see the other technologies, like Directed Energy Deposition or Wire Fed AM technologies, become more flexible to adapt to geometries with higher complexity. Or, perhaps a completely different type of machine/feedstock/energy delivery system architecture? In other words, I’ve been waiting for that one technology to drop that will shatter AM machines as we know it.

What is one thing that we need to do that we as an industry are not doing? 

 We need to stop promoting the technology itself as the key to world peace, while at the same time, expecting it to exhibit repeated performance of manufacturing technologies that have been around for decades or hundreds of years (castings, machining, injection molding, etc). As discussed in the book, many things within industry and within individual companies needs to change for this to be production hardened. In other words, bridle the enthusiasm a bit.

If I’m a company wishing to manufacture using DMLS, what advice would you give me? 

I would start with a series of questions that gets back to my point earlier that the technology itself is not an end. Why did you pick DMLS specifically? Did you research alternative AM technologies? What is the product you are wanting to produce? Is DMLS the most effective way to produce it? Are you wanting your product to be competitive from a cost standpoint, performance standpoint, etc? What is the objective of this product? By focusing on the product that ultimately gets sold to a happy customer, then DMLS may be a solution, or may not. By asking these types of questions first, we are more likely to arrive at better solution for the company. If DMLS is indeed the right technology choice; then drawing from the book, I would go down a road of preparing the company for the cultural, certification, organizational, talent management hurdles they would face.

What are the biggest hurdles to adopting AM? 

  1. Organizational Culture and Executive Long Term Commitment
  2. Certification Adherence
  3. Lack of Training (technician, engineers, executives)

Whats a good war story? I twice had a machine catch fire. 

That is interesting! Our AM war stories covered in the book are more aligned to cultural or organizational hurdles we’ve faced within companies. We had a lot of fun writing this section of the book and we enjoyed labeling each of the stories as they capture the essence of the challenges. For example, some stories are labeled, “Panning for Gold in Kansas”, “Pathfinder to Nowhere”, “Suckers for Sunk Costs”, “Who’s in Charge Here?”, “Engineering Rigor Mortis”, “Innovate NOW!” and many others. Each story is 100% true, company names were omitted and people’s names changed. They each are not only entertaining to read, but each has its own message relative as to what not to do when industrializing AM. For example, the “Panning for Gold in Kansas” story describes a company’s effort to scour existing products to convert to AM for cost savings potential only to discover later that the true value in AM in not directly building parts that were designed for conventional manufacturing, but rather re-designing the part for AM from the start to exploit AM design advantages, only then do cost savings occur.

SLM Solutions and Bugatti driving automotive sector with metal 3D printed parts

SLM Solutions, a German provider of metal additive manufacturing systems, has released more information about working with Bugatti, the French manufacturer of high-performance automobiles. The new information shows how 3D printing is used to develop critical components. Last year, the partners created a 3D printed brake caliper for the Bugatti Chiron. Recently the component underwent testing for serial production. Now, […]

Archinaut 3D printing technologies deemed ready for orbit

Technologies inside the Archinaut, a spider-like 3D printing satellite developed by off-world manufacturing company Made In Space, have been declared “prepared to operate in space.” Through testing in a Low Earth Orbit (LEO) simulation, Made In Space demonstrated the Archinaut’s ability to manufacture and assemble a variety of structures. Andrew Rush, President & CEO of […]

BEGO & Nexa3D Marketing Varseo XL: A Bigger, Better, Faster Dental 3D Printer

Each year, IDS offers a business summit for dental professionals, with this year’s event held in Cologne, Germany. Big news emerging from IDS 2019 involves a collaboration between California’s Nexa3D, a manufacturer of 3D printers offering stereolithography (SLA) for production-grade users, and BEGO, a provider of materials for dentist’s offices. Together, they are marketing the Varseo XL, to be sold by BEGO, headquartered in Germany. They will begin selling the Nexa3D-manufactured machine within the next year, via their dental reseller network.

Currently, BEGO provides both digital and traditional dental materials and solutions to medical professionals around the world, working from their own 3D printing experience too in ‘labside 3D printing’ with resins. While Nexa3D has manufactured the Varseo XL, BEGO has notably been behind the development of both the Varseo and the Varseo S, along with a range of dental 3D printing materials.

Together, the two companies are touting the Varseo XL as a 3D printer for dental labs that will rise above and beyond existing technology due to greater affordability as a system overall and added features that will allow dental technicians improved productivity; in fact, the Nexa3D team says that dental technicians will now be able to complete restorations in minutes, rather than hours. The new dental 3D printer is customized with Nexa3D’s proprietary Lubricant Sublayer Photo-curing (LSPc) technology, which functions via a high-speed light matrix.

Nexa3D and BEGO predict that dental offices will be able to print six times faster at ten times the volume, with a print area that is five times greater than any other dental 3D printer on the market. The Varseo XL, being marketed to dental lab practitioners, qualified resellers, and strategic partners, offers 3D printing of the following traditional dental materials:

  • Models
  • Trays
  • Permanent restorations
  • Bridges and crowns
  • Surgical guides
  • CAD/cast applications

The 3D printer allows continual monitoring and features cognitive software and integrated sensors—all meant to offer better performance and improved diagnostics of dental patients.

“The collaboration with BEGO is designed to successfully access the growing demand for digital 3D printers, a multibillion-dollar category. Under this multi-channel plan, Nexa3D will manufacture and BEGO will market and sell the Nexa3D dental printers under the Varseo XL label,” stated the two companies in a press release announcing their new partnership.

The Varseo XL will be showcased at IDS 2019 at booth M20/N29 – Hall 10.2, Koelnmesse, Fair Grounds, Cologne-Deutz until the fair closes on March 19, 2019. See the media kit for more information.

We have been following both BEGO and Nexa3D for years, along with watching the progression of the Varseo series of 3D printers; however, 3D printing in the dentistry realm is becoming more popular—and many patients are seeing incredible results—along with dental and orthodontics offices using 3D printing to help the process of going completely digital, and enjoying greater affordability in production costs.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: BEGO/Nexa3D press release]

 

Printed Noise Blocker Cuts 94% of Sound in Tube Experiment

Boston University researchers have created a metamaterial noise canceller that absorbs a large amount of sound while still maintaining airflow. Shaped like a doughnut-ring like structure, the printed noise blocker effectively eliminates 94% of sound, as is apparent in an experiment using a long tube playing out high frequency sounds from a loudspeaker. The metamaterial […]

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