Digital Removable Revolution
Technology helps improve outcomes and laboratory productivity
Robert Kreyer, CDT
Prosthetic dentistry is more than 20 years into the digital revolution. The years from 1994 to 2011 were devoted to clinical research on denture data acquisition and developing clinical and technical concepts. Since 2012, these concepts have been proven through the refinement of software and workflow processes. In fact, there is at least one published clinical study comparing the treatment outcomes of digitally made versus conventionally made complete removable dentures that concluded: "The digital process proved to be an equally effective and more time-efﬁcient option than the conventional process of prosthesis fabrication in the pre-doctoral program. The digital denture process was preferred and effectively used by pre-doctoral dental students under faculty supervision."1
Today, there are multiple options for digital scanning (or data acquisition) and design software as part of the process for digital dentures. Computer-aided manufacturing has been adopted by many laboratories using subtractive and/or additive workflow processes. In 2017 and 2018, there was an increase in demand for additive manufacturing with more printers and prosthetic product workflows. To date, there are still no 3D printing materials available that can quite match traditional denture teeth and base materials in terms of wear resistance, strength (to withstand high-impact environments), and esthetic layering. When printing materials that exhibit superior wear resistance and meet patients' high esthetic expectations are available, the adoption of digital denture workflows will increase exponentially.
As 2020 approaches, the benefits of a data-driven prosthetic workflow for the edentulous patient are becoming more and more obvious. If a dental laboratory or a dental office wants to provide optimal prosthetic treatment, digital acquisition and retention of data will be essential factors for long-term success.
Whether using desktop or intraoral technology, scanning has become an essential part of clinical prosthetic treatment combined with technical communication and collaboration. The ability to scan acquired clinical data in an analog or digital workflow and then export STL or other file formats will be what differentiates dental practices and laboratories from their competitors. A dental laboratory that does not have the ability to scan, register, and retain acquired clinical data will be left behind in the upcoming decade. Today, every dental laboratory should have a scanner to capture and retain clinical and technical data, whether as part of a hybrid-analog workflow or a fully digital one.
What is truly exciting is the forthcoming ability to scan edentulous soft tissue within the denture space. These scans of the soft tissue or mucosa are starting to enter the digital workflow for complete dentures. As seen in the screen capture file, the Primescan intraoral scanner (Dentsply Sirona, dentsplysirona.com) will capture edentulous mucosa or soft tissue very quickly and accurately. While Primescan is not currently marketed for edentulous scans, some dentists and laboratory technicians are creating digital workflows with this intraoral scanning technology. Using a touchscreen, the dentist or technician can manipulate images in any direction, and then enlarge to view areas of the edentulous denture-supporting space. As this technology becomes mainstream for complete denture prosthetics, aspects of traditional denture fabrication like tray selection, physical impressions, and gypsum materials will be slowly eliminated. Intraoral scanning is the true mucostatic impression technique that ultimately helps improve adhesion and surface tension with subtractive or additive manufacturing processes. With intraoral scanning technology, a digital denture space analysis can be done from a scan of edentulous soft tissue, which will improve both clinical and technical diagnostic capabilities.
In 2020 and beyond, new dentists should be able to replace their traditional/analog full prosthetic processes with digital dental workflows. Education will be the driving force behind both clinical and laboratory adoption of digital dentures. The ability to understand prosthetic variables with diagnostic data-gathering is the next phase of adoption. Digital diagnostic denture analysis will replace traditional model analysis for complete dentures.
What will dental laboratories that specialize in removable prosthetics look like in the coming years? First and foremost, there will always be a demand in the denture market for quality prosthetics. The high-end analog denture boutique laboratory will retain a niche market, although expanding its customer base will be dependent upon adoption of digital workflows to complement its fully hand-fabricated products. Digital design services will become an increasingly important revenue stream for laboratories that only receive intraoral scan files from clients for prosthetic design. The author sees this business model increasing and becoming the new kind of one-person digital laboratory. In the future, many dental offices will have the ability to print prosthetic products, but employing someone with the time and knowledge to design in-house will not be cost effective.
What is the future of removable prosthetic dentistry? Conventional impressions will be replaced by intraoral scan files, and facial scans such as CBCT will be part of the workflow as dentures are designed for the face and not just for the prosthetic space. When bandwidths such as 5G become available, the holographic image of the patient's head will be viewed in virtual reality by the digital denture design technician. With the patient's full facial features and functional anatomy projected from the benchtop, the technician will use virtual reality to finalize the prosthetic design. The technician is able to maximize stabilization through true anatomical articulation, and then create a functionally generated path of occlusion using a virtual or mixed reality software program and hardware. When virtual design is completed, it is downloaded into a programming stage where the prosthesis is prepared for computer-aided manufacturing. The manufacturing machines are robotically loaded, fabricated (3D printed or milled), unloaded, and cleaned to prepare for final inspection and the post-production process. Before finishing, a technician scans the printed or milled dentures, and then registers the scan file with the design file using the benchtop screen hologram of the patient's head and functional anatomy.
If dental technology is to move forward as an industry and as a profession, it must question all theories, concepts, techniques, materials, and equipment. Dental professionals who are open to the new ideas and processes that will truly make a difference in the lives of edentulous patients must embrace the future in pursuit of excellence in digital removable prosthetic dentistry.
About the Author
Robert Kreyer, CDT
1. Kattadiyil MT, Jekki R, Goodacre CJ, Baba NZ. Comparison of treatment outcomes in digital and conventional complete removable dental prosthesis fabrications in a predoctoral setting. J Prosthet Dent. 2015 Dec;114(6):818-25. doi: 10.1016/j.prosdent.2015.08.001. Epub 2015 Sep 26.