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| Paul Feuerstein, DMD |
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| Damon Adams, DDS |
Our editor-in-chief, Damon Adams, DDS, and our technology editor, Paul Feuerstein, DMD, recently discussed some of the trends in technology and their implications for the practitioner. Due to their respective connections with Dentistry Today, they find it fun once in a while to sit down over a glass of wine and dinner, catch up, and candidly talk about dentistry. In this case, they recorded their conversation for the benefit of our readers. Presented here are some salient portions of their discussion.
Paul, I bet our readers, especially the general practitioners (GPs), will be interested in hearing what you and your tech-loving peers are seeing and thinking in our rapidly changing world of dentistry.
Dr. Paul Feuerstein: GPs today are facing quite a bit of pressure to add several different technologies to their practices. Dental professionals are being bombarded with information coming from all sides: manufacturers, lecturers, authors, and academia. Furthermore, there is information crawling all over traditional and social media about new processes for instant crowns, instant smiles, and much more, while many dentists have been performing high-quality services for their patients with tried-and-true systems.
The most common comments we read are from practitioners who take “traditional” crown and bridge impressions and are receiving exceptional results from their dental laboratory teams. Are the new digital systems so far superior to well-taken physical impressions that there will be a dramatic difference in quality and fit of the restorations fabricated? How can a solo practitioner, or even a small group, justify a multi-thousand-dollar investment in, for example, a digital impression system and get a decent return on investment? How about adding in-office mills or 3-D printers, which now means someone has to design restorations and have patients waiting around for a finished product, and someone also has to be trained in machine maintenance? And what about 3-D digital radiography? Does the general practitioner really need all of that information that is available from the volume of data revealed when taking a CBCT scan? Maybe you have similar thoughts, Damon?
One can certainly argue that CBCT scans are immensely helpful in many different situations, such as in select endodontic and oral surgery cases, when treatment planning implants, for clinicians working in the arena of sleep disorders or diseases of the temporomandibular joints, and so much more. Although it represents a mesmerizing and almost “addictive” sort of go-to modern technology, dental professionals need to be thinking about the ways and reasons why one should be extremely selective over a patient’s lifetime in how and when this advanced technology is used and, above all, making sure it is employed only when the patient will benefit from its use and subsequent findings.
So, Paul, what is the driving force behind this situation where practitioners might feel a bit pressured to buy the latest technologies?
Dr. Feuerstein: Actually, although the dental consumers we serve are becoming savvier and asking for things like one-visit dentistry and “clear braces,” the real pressure is coming from the dental laboratories and their changing products and processes. New materials and manufacturing processes, like the choices in zirconia restorative materials (including the latest introduction of more aesthetic zirconia options by big players in the dental industry: IPS e.max ZirCAD Multi [Ivoclar Vivadent], Lava Esthetic [3M], ArgenZ [Argen], and BruxZir Anterior [Glidewell Laboratories], to name a few) that seem to be taking over much of the basic crown and bridge work, are created using computer-driven mills. Our laboratory teams can only create restorations from the latest materials using a digital workflow. The number of days left for plaster models, waxing, and casting grows shorter with every passing year. The new labs, even the smallest ones, have some sort of CAD/CAM system in place. There are a number of impression scanners that labs use to turn the traditional physical impressions taken, including any models sent, into digital files. If you think about this, scanning an impression or model is a secondary step, and this step can introduce miniscule errors into the process as opposed to scanning intraorally. So, even though many practitioners still prefer traditional physical impression techniques, the lab owners and their teams like, and many now prefer, to receive scans and to use digital files.
Of course, for those dentists who are staying with the tried-and-true gold, porcelain-fused-to-metal, conventional stacked porcelain, and other restorations, the advantage seems to wane—or does it? With new milling and 3-D printing of models, these more traditional restorations can also be done digitally and with the highest accuracy. And think of a small discrepancy in an impression or a stone model that was created with plaster that was not accurately weighed, with water not at the manufacturers’ recommended temperature and amount and not mixed properly for the precise length of time recommended. You have introduced discrepancies that are eliminated as possibilities in the digital workflow. In addition, there are economic advantages as there are no inbound shipping or pick-up fees and, in many cases, no model fees and a lower cost of the manufacturing and resultant lab fees charged to the practitioner.
This is all great, but if the clinician has been working for years with talented technicians in a smaller lab, and still wants that same high level of quality craftsmanship and especially, artisanship in the restorations created, moving away from this to in-office based technologies is a big and difficult decision. In my lectures, I often say that in committing to in-office CAD/CAM technologies, we are deciding to move beyond clinical work and into laboratory work as well. While this is definitely an exciting and appropriate choice for many dentists, it is not the easiest shift, nor is it always in the best interest of every clinician when all the implications are carefully considered. No matter how desirable it may be to have the latest and greatest technologies right at one’s fingertips, we have to realize that it may be a real challenge to afford the investment, implementation, training, and ongoing maintenance costs that are involved in owning in-office CAD/CAM and printing technologies. Furthermore, many recent graduates, who would otherwise likely be among the most aggressive of our colleagues in moving into the latest and greatest in-office equipment and digital workflow concepts, find themselves, on average, nearly $300,000 in debt coming out of their undergraduate degree and dental school. It is ironic, and frankly a bit discouraging, that this is the case at a time when we see such amazing technological innovations in dentistry for implementation in the dental office. How could this be changed to move technology forward? Perhaps even the educational model in the United States needs to be revisited and revamped?
Paul, what can you say to shed some light on this dilemma and possible solutions to the incorporation of more technology into the dental practice?
Dr. Feuerstein: Well, doctors can consider at least owning scanners. And to this point, many more dentists are sending in cases via scan files. However, the lab teams must have a method to at least receive and use these digital files. This does not mean that the lab must invest thousands of dollars in manufacturing machines. For example, there is a whole new group of labs doing work for other labs. Entrepreneurs have set up large design and milling centers that are exclusively available to dental labs—in effect, acting as subcontractors. This allows your favorite technician to have the latest technology and materials as available services while still controlling the design and finishing steps of the cases. There is a need for the technicians to learn how to virtually “wax-up” a case on the computer screen, but the learning curve is not steep. This software is more robust than what is commonly seen in a dental office; there are more design controls; and the technician, who has done many more crowns and bridges than the average practitioner, can spend more time tweaking the end result. Most labs use software with names that are now becoming familiar to dentists, such as 3Shape, Dental Wings (Straumann), and Exocad. This software can be found in most laboratories, and some dentists and their office teams are now learning how to use these as well. Also, when the cases come out of the commercial mills, the technicians have a large array of finishing, glazing, polishing, and tweaking tools. There are, of course, some practitioners who have done advanced studies and can create restorations equaling the technicians, but the majority of clinicians doing this don’t want to spend all of that time either learning or creating and will defer this work to their lab teams. Also, these companies are tweaking the lab software to make it a bit more user-friendly and offering it directly to the dentists. One example that comes to mind is the Exocad Chairside software that was recently released (exocad.com). As an aside, at a recent dental laboratory show, I came across a few companies, such as Full Contour (fullcontour.com), that allow busy labs to export cases to them and get the designs sent back for milling. This will soon be available to dental offices that have impression scanners and mills (and 3-D printers) but don’t want to spend the time designing. These companies are set up to receive your scan over the Internet, design the restoration for a small fee, and then export it directly to the office mill. Since this is all digital, and because there are facilities in many locations throughout the world, clinicians should be able to work virtually/digitally with a technician in an appropriate location in real time. Perhaps this the best of both worlds.
With this digital infrastructure and these new CAD/CAM materials, what should be we looking for?
Dr. Feuerstein: Well, as you know, there has been a huge push in the industry to get away from porcelain-fused-to-metal restorations, especially with single units, to zirconia and lithium disilicate restorations. We are being told, especially with zirconia, that these are almost indestructible. The compressive strength of zirconia is reported to be as high as 1,400 MPa. The recent introduction of aesthetic zirconia drops this down to the 700 to 800 MPa range, but it’s still very strong. However, in an earlier Focus On article in Dentistry Today (September 2016), Dr. Rella Christensen gave us some warnings and things to look out for when using some of the latest translucent zirconia materials. First of all, the research she has done shows that there can be inconsistency in the manufacturing, ingredients, and formulas for the zirconia blocks being sold and used. Not all manufacturers, nor dental labs, dealing with these products are created equal. For just a couple of examples, companies like Glidewell Laboratories (BruxZir and BruxZir Anterior) or Ivoclar Vivadent (IPS e.max ZirCAD and IPS e.max ZirCAD Multi) have amazing quality controls in place and work with a team of chemists and scientists to ensure that clinicians and patients are getting the excellence in product performance that is expected. Like anything else, there are both name brands and generics, so doctors need to know details about the dental material being prescribed and verify with the lab owner the source and exact makeup of the material being used to fabricate their restorations. In addition, Rella found that, although the aesthetic zirconia material had good strength values, improper occlusal adjustments and polishing techniques, as well as poor prep design, can lead to premature fractures. These materials also have different thickness requirements, so clinicians must be aware of this and make any needed adjustments in the preparation design for any given material and/or material usage.
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| Clockwise from upper left: Lava Esthetic (3M), ArgenZ (Argen), IPS e.max ZirCAD Multi (Ivoclar Vivadent), and BruxZir Anterior (Glidewell Laboratories) |
Paul, you are spot on! By the way, beware gray market materials! Stick with quality materials from quality manufacturers and laboratories. An old cliché is relevant here: You get what you pay for. And gone are the days when one prepared a tooth and then thought about which material would be “the best one” to use. Thorough diagnosis and treatment planning, along with thoughtful material selection, is required before beginning the preparation of any tooth. Fortunately, when prepared in a minimally invasive way, the clinician now has aesthetic and conservative options to work with ever-improving direct composite resin choices, along with lithium disilicate and a variety of zirconia options, when required.
So Paul, you have been talking a bit here about the dental laboratories, but what is going on with in-office restoration design and creation?
Dr. Feuerstein: The terms “one-visit dentistry” and “crown in a day” are now a reality! CEREC (Dentsply Sirona) has been doing this for more than 30 years and leading the way, followed by E4D, now Planmeca, and others. The in-office design software and milling has become extremely accurate, with more materials available than ever before, including zirconia. The most confusing but exciting development, though, is having components from various manufacturers that can “talk” to each other. This is called having an “open” architecture. There are impression scanners, design software, mills, and 3-D printers available from a variety of manufacturers that seem to allow the office to pick, choose, and set up the same way you would buy stereo components. Of course, this is not just plug-and-play, but it is evolving and becoming more simplified quickly. There are also third-party distributors, including many of the existing ones, that will help the dentist pick and choose the components and then stitch them all together for the office. This is, of course, helpful when something goes wrong and the practitioner is not sure which component is responsible. Some of the scanner manufacturers also have relationships with software and milling manufacturers and can guide the office through the setup. Companies like Exocad have software that can work with all components and are even bundled in the scanner or mill software and work invisibly. Glidewell has created a complete system using the iTero scanner with its software and mill. We are, and will be, seeing more of this merging of systems and companies, which will allow the doctor to set up a system now and, when a new product comes into the marketplace, add only one piece to upgrade instead of changing the whole system.
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| OccluSense (Bausch) |
The advent of 3-D printers, along with new materials, will also be a game changer. Damon, you will remember that my column in August 2018 touched on some of the advances in 3-D printing. Although we are not quite ready to print “permanent” crowns and bridges, this technology is advancing rapidly and should soon give us the ability to do so. For now, even though some of the current materials have been in the mouth for 5 years, the crowns are still classified as “provisionals.” Of course, using composite or polymethylmethacrylate, we can now print provisionals. The cost of printing is minimal—less than $10—but right now, the printing process takes at least 20 to 45 minutes. This is not practical for a single crown temporary. With digital case planning and clever use of the software prior to the patient visit, printing will allow practitioners to create long-term/long-span temporaries in the office at a great cost savings over lab-fabricated temps. Printing also covers a range of products, including models, retainers, mouthguards, surgical guides, and more. In fact, a couple of companies are now printing dentures. Dentca, for example, has an entire digital workflow once the edentulous impressions are scanned. Of course, we currently cannot scan a totally edentulous arch.
Using a Carbon printer (carbon3d.com), the denture base and the teeth are printed and then fused together. Materials and printers from 3DSystems/NextDent and EnvisionTEC are also printing dentures. If the clinician has an in-office printer, a patient can get a spare or duplicate if one is lost or damaged in less time and with less cost than when done by the dental lab team. Finally, we are seeing a proliferation of new digital orthodontic systems, such as SLX Clear Aligners (Henry Schein), Insignia Clearguide Express (Ormco Products), Clarity Aligners (3M), and Smart Moves (Great Lakes Orthodontics), following the lead of Invisalign and Clear Correct, of course.
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| Clockwise from upper left: iTero (Align Technology), CEREC AC (Dentsply Sirona), and Emerald (Planmeca) |
Thinking ahead, with software and the ability to print all of the sequential models—or, soon, the actual aligners—these technologies will revolutionize this arena. As we continue in this exciting area, we are seeing that NextDent now has more than 40 materials allowing us to print many things, from models to night guards to provisional crowns. EnvisionTEC and VOCO have a barrage of materials that are coming out at a rapid pace. Other companies are in the hunt as well.
Speaking of interoperability, Paul, where does cone beam technology come into this picture, and how does it fit in the digital workflow?
Dr. Feuerstein: My answer to your questions could really be long if we had more time, so let me just make a brief few statements. I often get asked why a GP should consider cone beam in his or her office. I suppose (facetiously) if all you do is straight restorative, and never do endo, place or restore implants, treat periodontal disease, or perform any extractions, then I suppose there is limited value. The information obtained from a scan is not only a better diagnostic tool, but also a patient education system. Showing a patient periodontal bone loss on the scan is quite dramatic. A patient in pain, especially if there is previous endodontic treatment, can be diagnosed for fractures, additional canals, or apical lesions easily, and it can be demonstrative to the patient and doctor. As far as restorative, the impression scans can be superimposed on the cone beam for the diagnosis and treatment planning of many procedures, particularly implant placement. Even if the dentist does not place them, the position of the crown preoperatively could help determine where (and if) an implant should be placed for optimal physics. We have all experienced having to create an abutment and a crown on a strangely placed implant. This can be made more predictable, provided the anatomy and bone will allow it, with this merged technology. Adding 3-D printers to the mix, surgical guides can be created in the office for less than $10! And, with new software and tracking devices, occlusion can be determined using the patients’ own TMJ movements, creating virtual articulation. As an aside, the Bausch corporation has just launched a digital articulating paper called OccluSense (occlusense.com) that not only records the red marks on a patient’s teeth, but displays them on an iPad, showing the actual forces of each mark. There is also a short video that can be made showing the patient’s excursive movements.
Well, Damon, it has been great to discuss what’s going on with you again! We have focused on a small section of some of the new technologies now available. There are many new processes, computer programs, restorative materials, cements, practice management systems, and much more that have been developed with amazing technologies. It is so exciting to know that there is plenty of material for us to continue writing and lecturing about in this area without being repetitive. As you know, I spend a lot of my time going to meetings as an attendee and a lecturer, so I will always do my very best to keep you and our readers informed on many of the latest new innovations in dentistry.
Paul, as always, it has been an honor and pleasure to talk with you about even a small slice of the ever-changing world of dentistry. Thanks for taking the time! Be well, my friend, and travel safely!
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