|Gerard Kugel, DMD, MS, PhD; Scott D. Ganz, DMD; and Tarun Agarwal, DDS|
In this roundtable discussion, conducted by Paul Feuerstein, DMD, Dentistry Today’s technology editor, we focus on the restorative aspects of digital dentistry and look at how it is used by general practitioners (GPs) in everyday practice. There has been a lot of hype about digital impressions and 3-D cone beam technology, with some claiming it is easy to do and very predictable, implying that the technology can really do all the work. This may be an overstatement, and we probably need to go back to an old technology mnemonic called GIGO (“garbage in, garbage out”). The GP must still have the proper skillset and a good understanding of the technology (or technologies) being used. This requires a fair amount of education, far beyond the one or 2 days of training offered by an equipment installer, for example. Plus, we cannot throw out all the basic information that we started with and replace it with all new ideas. Through the eyes and minds of our assembled leading experts, Drs. Tarun Agarwal, Scott Ganz, and Gerard Kugel, we discuss (1) what digital impressions offer to the practice and how we can efficiently utilize this technology and (2) the emergence of 3-D imaging, including cone beam radiography. And finally, we talk briefly about some of the new restorative materials that have been recently introduced into the practice of dentistry.
Let’s start with you, Tarun, beginning with basic restorative dentistry. How has the advent of the digital impression improved your delivery of care? Furthermore, you have a lot of experience with “one-visit dentistry” and are a strong advocate of its merits, but let’s also drop back a step and look at the general workflow and advantages.
Dr. Agarwal: Digital impression technology has revolutionized the way in which we are able to deliver dentistry. The improvements that this technology brings to the table for delivering care in our offices includes the ability to deliver quality restorations and quality outcomes in a reduced amount of time.
Workflow of single-visit dentistry does not mean that chairside work is better than lab-fabricated work. At the end of the day, it can be more patient-friendly than the 2-visit, lab-fabricated restorative work. It is not about economics or being cool; rather it is about the patient, with the advantage being the ability to complete treatment faster and in fewer visits. We have found that this workflow produces fewer complaints of postoperative tooth sensitivity that is, in some cases, due to loose and/or leaking temporaries. With a one-visit CAD/CAM restorative treatment, the clinician can seal the tooth right away, which is associated with less post-op sensitivity. Also, with same-visit dentistry, you can rethink and refine your prep designs with immediate digital impression feedback. This can lead to improvement in your preparations. It can even lead to saving more tooth structure with more partial-coverage restorations, as we don’t have to think about those fragile temporaries or worry about a prep that must be extra retentive just to get through the temporary process.
|Figures 1 to 4. Cone beam CT (CBCT) 3-D imaging provides clinicians with an unparalleled appreciation of a patient’s individual bony anatomy including teeth, roots, nerves, adjacent vital structures, and pathological entities.|
Gerry, you have certainly studied many of these materials both from in-office blocks and lab-processed CAD/CAM materials. Are PFMs and full-gold restorations dead?
Dr. Kugel: Sadly, they are dying fast! Even though we have little clinical data on zirconia crowns to date, and certainly not long-term, they have become a standard procedure in dental offices for the posterior region of the mouth. When I’ve recently asked dentists in my lectures how many of them have read one article on zirconia, less than 10% raise their hands. Although we talk about evidence-based dentistry, it seems that most clinicians are not using scientific, evidence-based information to determine the materials of choice in their practice. And, as far as in-office CAD/CAM technology goes, I feel it is certainly a viable option for many offices, but not all. Some practices are not equipped, nor is there a major benefit to have CAD/CAM. Doctors need to evaluate their practice and their own needs.
|Figures 5 and 6. The use of advanced interactive treatment planning software aids in understanding potential implant receptor sites for both the surgical and the restorative phases.|
|Figures 7 and 8. The CBCT data allows for accurate planning of dental implants, leading to fabrication of surgical guides by either CAD/CAM or 3-D printing, even on in-office devices. (Figures 1 to 8 courtesy of Dr. Scott Ganz.)|
|Figures 9 and 10. It is now possible link the CBCT data with implant planning and CAD design software to produce machined restorations from a variety of new and improved materials. (Labwork and Figures 9 to 11 courtesy of Valley Dental Arts Lab, Stillwater, Minn.)|
Tarun, you have been a CEREC user since its inception through its development stages and to the present day. You have used many materials for partial- and full-coverage restorations. How has the evolution in dental materials changed your treatment plans?
Dr. Agarwal: In the early stages, one of the great fears was material strength and potential breakage. With the advent of high-strength ceramics and the evolution to be able to design and mill restorations chairside as well as in the lab, a new avenue for strong and predictable in-office restorations has been opened. As far as materials go, we are seeing a move toward hybrid ceramics, such as ceramics combined with composite (polymer ceramics) that have more resilience and properties that more closely mimic the enamel with excellent wear and flex properties. And, of course, zirconia is also playing a big role in material advancements.
Gerry, Tarun just mentioned chairside zirconia. Are all zirconia products the same? Is there any real standardization? In other words, whether in the office or lab-fabricated, are we on a level playing field?
Dr. Kugel: No. Not all zirconias are the same; however, those that are being marketed by the major manufacturers are very reliable. For example, companies like Jensen, Ivoclar Vivadent, 3M, and Glidewell Laboratories all produce high-quality products. There are some products that claim to be a millable zirconia, but be aware that these have a small amount of zirconia in them and are not truly zirconia blocks. Also, be aware that monolithic zirconia is not translucent. When labs offer you more translucent zirconia products to improve aesthetics, the strength of the material has been decreased due to changes in the makeup and crystalline structure of the material.
With this surge in zirconia materials, Gerry, I have a fear that these new materials may be too hard. Are they affecting the opposing dentition? And I have heard that some mills create a higher polish than others, and that there could be issues with our chairside adjusting.
Dr. Kugel: The reality is—and studies have shown—that properly polished zirconia is kind to the opposing dentition. However, the question is how many dentists actually polish the zirconia restorations adequately after (occlusal) adjustments are made. They should be polished out of the mouth after they have been tried and adjusted, and this is not a trivial matter. The other question related to hardness, though, is if I have a full-mouth reconstruction and my posterior occlusion in all zirconia, will this affect the muscles and joints long term? We have little data on this.
|Figure 11. An implant-supported CAD/CAM titanium-milled bar.||Figure 12. Education is paramount to learning the necessary skills to diagnose, treatment plan, manage the soft tissue, place and restore implants while avoiding complications.|
|Figure 13. Live hands-on surgical programs are ideal venues to learn from experience mentors who can help clinicians gain extra confidence to manage these procedures in their private practice. (Figures 11 to 13 courtesy of AIE Advanced Implant Education [aiedental.com].)|
Okay, Gerry, but then what are we seeing even in the short clinical time we have had, in terms of failures?
Dr. Kugel: I have not seen a single zirconia or lithium disilicate crown fail in my practice. What I have seen are failures caused by placing zirconia crowns with open margins and/or the fact that they may be unaesthetic restorations. I also think that doctors are not being as meticulous as they should be during cementation. The technique guide available from Glidewell Laboratories is a good resource. Finally, I cement many of my crowns using proper isolation techniques and devices, since my occlusion and polish are always done prior to cementation. When cemented properly, these crowns are very difficult to remove, as many of us have found out.
Scott, I am curious. We can now do an intraoral scan in full color, providing a 3-D virtual study model for case presentation and treatment planning. We also have a similar situation with CBCT technology. And, of course, we can merge these. In simple terms, how does this help your ability to treatment plan, and does it really provide the patient with more concrete information to understand?
Dr. Ganz: Advancements in computer hardware, graphic cards, memory, and high-resolution digital displays are paving the way for ever-improving diagnostic capabilities. The new digital workflow—which, by the way, is not new in reality; just more prevalent—allows for clinicians and dental laboratory teams to explore patient anatomy in greater detail before the scalpel touches the patient. We should know that CBCT is a lower-dose imaging choice over conventional CT scans, but this technology provides a more appropriate and true 3-D evaluation of a patient’s individual anatomical presentation. Interactive treatment planning software can now take advantage of the hardware improvements to help us assess relative bone density, plan for implant receptor sites, bone grafting procedures, and even links to the restorative phase with ever-increasing accuracy. However, that stated, CBCT does not provide the best surface detail, especially when there are teeth and/or metal artifacts in the field of interest.
The ability to merge either an intraoral scan or an optical scan of a stone cast provides near-perfect surface reproduction, which can be superimposed on the CBCT dataset. Additionally, a diagnostic wax-up or duplicate of a patient’s denture can be utilized to assess the relationship of the desired tooth position to the underlying bone. In this manner, we can all practice true and accurate restoratively driven implant reconstruction, meeting the patient’s desires for function and aesthetics. After all, our patients are not coming to us for implants; they come to us because they want and need teeth for improved quality of life.
We can also illustrate the entire treatment plan in front of the patient with our computer simulation, and this is a great aid in patient treatment acceptance. Perhaps the most exciting advancement has been with 3-D printing. Individual clinicians can use this technology to provide models of the maxilla or mandible to show the patient, or to print an accurate surgical guide based on the CBCT plan. Remember, though, “It’s not the scan, it’s the plan!”
Tarun, similarly, one aspect that is intriguing is that with new, accurate full-color scans, we can make virtual study models and use these for treatment planning and patient education.
Dr. Agarwal: I envision the day when this will become the standard. Eventually, there will be no more study models that need to be poured, trimmed, and shown to the patient in all white or yellow stone. Instead, virtual study models can be shown in full color. We can look at the bite on the screen and use virtual articulation, which is far more accurate than a typical hinge from the lab. Measurements can be taken and transcribed to the software. We can go through excursive movements and see wear patterns and other occlusal issues. With full color, our patients can see a lot more than an intraoral camera view of one or 2 teeth or even a full series of photos where they mentally extrapolate what we are showing them. As we move forward with smile design, it will be a lot more powerful and realistic than a Photoshop-like smile simulation presentation. Adding face scans with the newer units will give the patient, and us, a better and more accurate preview of the outcomes of what we are proposing.
Scott, implants are undergoing a giant surge as an option for tooth replacement. They seem to be more predictable with the digital tools, and it seems that the public has begun to accept this treatment far more easily than certain traditional bridgework. I personally have found patients easily accepting an implant to replace a missing first molar versus the old 3-unit bridge option. Is that your experience?
Dr. Ganz: Interesting perception! If you watch television, use the Internet, or listen to the radio while driving to work, there are many times when we are inundated with ads about “tooth replacement” with dental implants, and often they are referred to as “permanent tooth replacements.” I would venture to say that the surge in acceptance for implants has more to do with direct-to-consumer marketing than anything to do with digital technologies. The concept of “teeth in an hour” or “teeth in a day” or “all-on-4” have become part of our vocabulary, not because we are better at what we as dentists do, but, in my opinion, related more to the “giant surge,” as you stated, in savvy marketing.
Scott, there are now situations in which treatment plans are a bit more complicated. With combinations of materials, implants, and digital case planning, we are doing very different-looking cases. How do we keep up with all of this, and how do we know what will actually work in the long term? Patients are spending big dollars and will be very disappointed, to say the least, if our work starts to fail prematurely.
Dr. Ganz: We are fortunate to live in a time when technology is moving our profession in new and sometimes unchartered waters. I am not certain that treatment plans are becoming more complicated, since patients still have the same problems. I would state that we are finally climbing the learning curve to understand that in the past we did not know what we did not know. Meaning that the advent and acceptance of 3-D imaging technologies has afforded us new tools to improve our diagnostic capabilities, leading to a more accurate assessment of individual patient presentations beyond previous 2-D imaging modalities. Improved diagnostic accuracy, along with improved computer-based patient presentation tools, are leading to better case acceptance. By the way, I addressed this same topic in Dentistry Today in 1995. Therefore, if we can plan better, we can also plan to use the most current materials to produce superior results that should avoid complications and failure. The new digital workflows help also to improve our communication with all our treatment team, and especially the dental laboratory technician team. I have a very positive attitude when the technology is used correctly and, as with guided implant surgery, “the template is only as good as the plan.”
Gerry, as we see more in-office processes and the need for expensive equipment and retraining the dental technicians on software instead of carving wax, should the smaller labs simply consider shutting their doors?
Dr. Kugel: I’m not sure small labs should shut their doors, as they are often in a unique position to become boutique lab providers, limiting their clientele to those doctors who might be very demanding or just want a more personalized approach. Realize that not all dentists want to go completely digital. I work with a lab in Boston in which the dental technicians are true artists and choose not to do everything digitally. I think the labs that are going to survive, particularly the smaller labs, will be those that can embrace the new technologies, and combine them with the art and science of their more historically traditional ways.
Tarun, you mentioned something to me earlier was a great point. If all the parties (the GP dentists, lab technicians, and specialists) are using these technologies, is there is a common language and an easy way to discuss and exchange the information while developing the treatment plan?
Dr. Agarwal: I am seeing a much greater collaboration of care. The ability to communicate with the specialist or lab in their own terms, with the added possibility of doing this in real time with things like Facetime, Skype, video conferencing, etc—the ultimate winner has been the patient. With the software and scans, you can share screens with the lab teams, discuss the preparation and/or restoration designs, or go over implant placement plans with the specialists. It is great when you have a lab team member or another GP take control of the screen, pointing out something that can or should be done before the case is finished. Everyone is on the same page during fabrication, so there are no surprises at the insertion visit. It allows us to work more closely together, and when a lot of information can be visualized, it is much easier to speak in a language that we can all understand.
So far, Tarun, we have focused on restorative issues. How is all of this entering into other treatment modalities such as orthodontics, bruxing appliances, or even sleep apnea?
Dr. Agarwal: This tells me that dentistry has gone digital. It is way beyond chairside dentistry. No longer just radiographs or implants, it is permeating all areas of dentistry. We have digital 3-D endodontic planning with guides for minimized access. We have orthodontists with not only study models but digital virtual plans that both the clinician and patient can see. We are seeing the digital flow in the design and fabrication of bruxing appliances with the ability to print models and appliances. With respect to sleep apnea, by combining data CAD/CAM data and CBCT data, the clinician is able to get a better view of the patient’s chances for success—by evaluating the nasopharynx, tongue size, palatal width, and joint conditions.
You have been part of the digital evolution since its inception, Scott. Do you have any words of wisdom for clinicians who are trying to become more involved with the integration of the digital workflow and dental implants?
Dr. Ganz: Yes. Education, education, and more education!
As technology continues to evolve, voids in our initial dental school experience become apparent with an increasingly obvious need to fill these educational voids. When it comes to the new digital workflow, there is a pervasive attitude that clinicians who purchase technology will somehow intuitively know how to fully and successfully incorporate these technologies into their practices. This is often not the case, and support must be made available as most clinicians’ desire to keep up with new concepts, treatment modalities, and digital tools that empower them to enhance their practices and improve patient care.
Clinicians can become involved with organizations that provide educational opportunities to learn a variety of innovative techniques in courses presented by some of the finest clinicians in the world. There are both didactic and hands-on courses where clinicians can learn about new products such as intraoral scanners, CBCT devices, CAD/CAM abutments, or monolithic zirconia restorations. Many clinicians who wish to improve their level of confidence with dental implant procedures have a plethora of different educational programs to choose from, in-person or online. There is a great need for credible live hands-on surgical and restorative programs to deliver a high level of education for clinicians who wish to expand their knowledge and skill levels. Therefore, my best advice for clinicians who want to be involved in our rapidly changing world is to seek out and pursue educational opportunities that can enrich your life and improve your clinical abilities. Your patients will be that much more appreciative.
Dr. Feuerstein: It has been a pleasure getting all 3 of you together to discuss these topics related to technologies in dentistry. You have given our readers, and me, some great insights in our very dynamic and fast-changing field of dentistry. The discussion has certainly added some clarification, but at the same time, spurred me to think of even more questions that we do not have the time or space to entertain. Dr. Damon Adams, our editor-in-chief, would also like to publicly thank all of you for accepting the invitation to participate in this roundtable discussion, featured exclusively in Dentistry Today!
Dr. Agarwal, a 1999 graduate of University of Missouri-Kansas City, maintains a full-time private practice emphasizing aesthetic, restorative, and implant dentistry in Raleigh, NC. His work and practice has been featured in numerous consumer and dental publications. He has completed extensive continuing education with many dental leaders and regularly presents to study clubs and dental organizations nationally. He can be reached via email at email@example.com or via the website raleighdentalarts.com.
Disclosure: Dr. Agarwal reports no disclosures.
Dr. Ganz graduated from the University of Medicine and Dentistry of New Jersey (UMDNJ) Dental School and then completed a 3-year specialty program in maxillofacial prosthetics at MD Anderson Cancer Center in Houston. While maintaining a private practice for prosthodontics, maxillofacial prosthetics, and implant dentistry in Fort Lee, NJ, he is also on the board of directors of the International Congress of Oral Implantologists (ICOI), on the implant faculty of many preceptorship programs nationally, on the staff of Hackensack University Medical Center, and on faculty at Rutgers School of Dental Medicine. He was a founding member of the Simplant Academy, headquartered in Lueven, Belgium. He is also past president of both the Computer Aided Implantology Academy and the NJ section of the American College of Prosthodontists. He has served as a consultant for numerous companies for the past 27 years. He is on the editorial staff of several publications, has published many articles in scientific journals, and has contributed to 14 textbooks to date. He also authored An Illustrated Guide to Understanding Dental Implants and Computer Guided Applications for Dental Implants, Bone Grafting, and Reconstructive Surgery (Elsevier). He has presented internationally on the prosthetic and surgical phases of implant dentistry, and has been a featured speaker for the ICOI, the Academy of Osseointegration, and others. He is considered one of the world’s leading experts in the field of computer utilization for diagnostic, graphical, and treatment planning applications in dentistry. He can be reached via email at firstname.lastname@example.org.
Disclosure: Dr. Ganz is co-director of advanced implant education and director of the Ganz Institute of Applied 3-D Implant Reconstruction.
Dr. Kugel received his PhD in dental materials and his executive certificate in management and leadership from the Sloan School of Management at Massachusetts Institute of Technology. He is the associate dean for research and professor of prosthodontics and operative dentistry at Tufts University School of Dental Medicine (Boston). He is also part of a group practice, the Boston Center for Oral Health, located in Back Bay, Boston. He is a Fellow in the American and International Colleges of Dentistry, the AGD, and the Academy of Dental Materials. He is on the board of directors of the CR Foundation. With expertise in clinical research and aesthetic dentistry, he is also a reviewer for multiple scientific journals. He is on the editorial boards of several dental publications and has served as editor-in-chief of Inside Dentistry. He has published more than 120 articles and many abstracts in the field of restorative materials and techniques, and he has given more than 300 lectures internationally. He can be reached via email at email@example.com or by visiting the website drgerardkugel.com.
Disclosure: Dr. Kugel reports no disclosures.
Editor’s note: Dr. Paul Feuerstein’s monthly column, Technology Today, will return next month.