The Reference Denture Technique
Requirements and benefits of an increasingly popular digital process
Over the years, advances in digital technology have affected the many protocols of dentistry to varying degrees. One of the areas in which the effect of digital technology has been the most significant is in prosthetic dentistry, where among other advantages, it has enabled the efficient and accurate fabrication of new full-arch prostheses by digitizing the existing ones in a process referred to as the reference denture technique.1,2 Recently, Inside Dentistry spoke with Wael N. Garine, DDS, a clinical assistant professor at the University of Rochester and director of the Seaside Study Club in Jupiter, Florida, who regularly uses the reference denture technique.
Inside Dentistry (ID): What is the reference denture technique?
Wael N. Garine, DDS (WG): The reference denture technique involves using your patients' existing dentures that they present with to fabricate their new dentures. This allows us to leverage all of the information that we already have as a starting point and improve on it instead of starting from scratch.
ID: It seems so simple, so why is it so significant? What are the benefits?
WG: The concept itself is not new, but the process was much more cumbersome with analog techniques. It was time-consuming to the point that the benefits were often not worth the time. Digital technology makes it so much easier, more efficient, and more predictable.3 We can save significant amounts of chairside time, which is beneficial for both the practice and the patient. The process is very predictable because the starting point is a prosthesis that has already been successfully used. In addition, we can print or mill the final denture, which capitalizes on the repeatability factor of digital dentures. If a patient loses a denture, you can use the digital file to simply reprint or re-mill it. That knowledge also gives patients peace of mind.
ID: So, does this technique only need to be used once on each patient? Once a patient has a digital denture, is the fabrication of all of his or her subsequent dentures just a matter of reprinting or re-milling the same file?
WG: Not necessarily. If a patient undergoes bone resorption and/or soft-tissue changes, then that can require us to reline the denture and modify it slightly. Nonetheless, the bulk of the work is already done in terms of tooth selection, position, and occlusion. If we need to remake a denture after 5 years, we only need to perform a reline impression and possibly a new bite and then rescan it.
ID: Are you only scanning for the reference denture technique, or are you scanning edentulous arches for new denture patients too?
WG: We have found that scanning the edentulous arch is possible but not predictable. For patients who walk in with no teeth at all, we still start with analog processes. We do, however, scan their final dentures so that we have the files for the future.
ID: What are the technology requirements for the reference denture technique?
WG: Regarding technology, simply having an intraoral scanner in your office is the only requirement. Many scanners have dedicated modules for scanning dentures extraorally as opposed to scanning intraorally; the algorithm is a bit different in terms of the artificial intelligence. However, even having an intraoral scanner is not an absolute necessity. If you have access to a nearby laboratory with a desktop scanner, they can pick up the denture, scan it within a few minutes, and return it to your office for the patient the same day.
ID: Do you have any recommendations for improving success?
WG: I have found that wearing black gloves works very well when scanning a denture extraorally because they do not interfere with the scanner tip. With any other color, when you are holding the denture in your hand, the scanner can capture your thumb or finger and distort the scan slightly. Beyond that, the key is just to use a good scanner with a denture scanning mode and to practice, practice, practice. The first few times that I used the technique, scanning took me a while, but now, I can scan a denture in under 90 seconds. There is a specific sequence to scanning dentures, which depends on the scanner that you have. For example, I scan the intaglio surface of the denture first and then scan the occlusal aspects. Different scanners have different sequences. Following the manufacturer's instructions is critical, but ideally, the steps should be learned directly from a trainer. Scanning a denture is not a haphazard process. There is a method to be followed to get the best results possible.
ID: Do you envision the reference denture technique becoming even more refined, easier, and more effective?
WG: There is no question about that. In the future, this will be the primary way of making dentures. The reference denture technique allows us to be both more efficient and more predictable. As scanning technology improves, more scanners will have specific modules for dentures, which will make the scanning process itself even easier.
ID: Could this technique be adapted for other applications?
WG: We already scan existing crowns to replicate them. In addition, we recently had a patient with an obturator that we were able to scan in order to fabricate a reference obturator. In maxillofacial prosthetic dentistry, making an impression for a palatal defect can be very challenging for both the dentist and the patient, so if the patient presents with an existing maxillofacial intraoral prosthesis that can be scanned, duplicated, and used in the fabrication of the new one, that is a transformative opportunity. I use the reference denture technique every day in my practice. At this point, 80% of the dentures that I make are reference dentures. If a patient walks in with an existing denture, the process is so efficient now that there is no reason whatsoever for me to start from scratch. Familiarize yourself with this technique, and it will definitely improve your workflow and efficiency.
References
1. Scherer M. The "reference denture technique" - key for simplifying digital denture workflows. LearnDentistry website. https://learndentistry.com/reference-denture-technique/. Accessed May 31, 2022.
2. Kukucka ED. Scanning reference dentures: this is the optimal way. 3Shape website. https://blog.3shape.com/en-us/2021/scanning-reference-dentures-optimal-way. Published June 11, 2021. Accessed May 31, 2022.
3. Chen L, Li D, Zhou J, et al. Duplicating complete dentures with conventional and digital methods: comparisons of trueness and efficiency. Dent J (Basel). 2022;10(3):35.
