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This article presents two perspectives in a dental partnership—the laboratory and practice—regarding the use of a digital scannable, powder-free vinyl polysiloxane (VPS) impression material. By removing a time-consuming step of mold pouring, the need for remakes and the risk for inaccuracies are eliminated, ultimately resulting in a better product for the patient.
The Dental Laboratory Perspective
Digital scanning is proving to be one area in which laboratories can improve the results they provide to dental practice partners. This technologic advance enables the laboratory to manipulate and interpret data with more predictability than when it utilizes traditional processes.
With conventional impressions, dental laboratories and practices face an inherent risk for distortion. Each of the three points in the process—from mouth to impression to model pour—presents this potential and can reduce the predictability of the laboratory’s outcomes. Powder-free scannable VPS impression materials enable the laboratory to reduce the risk for distortion by eliminating the need for the model pour, which can be dependent on several factors that affect accuracy: tray selection, number of pours, amount of material, and type of impression material. Thus, eliminating model pouring minimizes the differences between the model and impression, while also significantly streamlining the laboratory’s workflow.
Importantly, using powder-free scannable impression materials will enable dental practice collaborators to enjoy the benefits of digital technology without having to invest as much as $30,000 in an intraoral scanner. Practices just need to use a scannable VPS impression material and send the impression to the laboratory. The laboratory, in turn, does not have the expense of applying powder to the impression; it simply uses the in-laboratory impression scanner and receives almost immediate access to extremely rich digital data.
Scannable impression materials, such as Flexitime® Fast & Scan™ (Heraeus Kulzer, www.heraeus-kulzer-us.com) (Figure 1), generate a crisper scan compared with conventional impression substances. These materials offer other significant benefits for the dental laboratory. First, not having to pour a model or use a powder yields savings in materials. Second, and more importantly, the laboratory no longer has to wait a day and a half—the time that drying cycles and fabrication requires. Instead, scannable impression materials need only 12 minutes before being ready for digital manufacturing. Third, because scannable impression materials can help reduce the risk for distortion, the laboratory spends less time—and expense—on remakes.
The availability of scannable impression materials demonstrates a classic example of a technology advancement that benefits not only dental laboratories and their dental practice partners, but also patients.
The Dental Practice Perspective
Digital dentistry is a reality in modern dental practice. For instance, the use of monolithic zirconia restorations has increased in popularity. These are high-strength, all-ceramic solutions that require only 0.5 mm of occlusal reduction, making monolithic zirconia restorations ideal for posterior teeth with short clinical crowns such as second molars (Figure 2). These types of restorations are always milled, which means that the information the dentist sends to the laboratory must be digitized. The restoration is designed using CAD/CAM technology and then milled.
Another popular restorative material in use is lithium disilicate, which can be pressed or digitally milled. However, many dentists may not realize that laboratories are milling the wax patterns they use to press the final restoration. These are just two examples of the many ways that the digital revolution has changed the dental profession; the list of innovations includes orthodontic aligner technology, milled nightguards, and milled provisional restorations.
Why digital? From the vantage point of technical dentistry, practitioners can improve their accuracy outcomes by using digital methods compared with the results they obtain with more traditional fabrication techniques. Pouring a stone model from an impression introduces the chances for inconsistency due to the physical properties of the gypsum. Then, as practitioners work on a stone model, they can alter the shape of the model, further increasing the risk for inaccuracy. To prevent other materials from sticking to the stone, dentists add lubricants and spacers that bring film thickness with them. All these issues can contribute to a poor clinical result. Consequently, each step that can be replaced with a digital process increases the degree of accuracy and efficiency in manufacturing.
Deciding whether to incorporate digital impression technology into the dental office can be complex. Dentists may be considering many factors, including price barriers, learning curves, technology management, and image handling. Milling requires digital data, so laboratory technicians pour a stone model or powder the intaglio of an impression, enabling them to scan.
The dentist–author of this article has found success with the Flexitime Fast & Scan powder-free scannable impression material. With the same great handling and physical properties of conventional impression material, Fast & Scan was able to fit immediately into her existing systems and procedures without any upfront investment in technology.
Moreover, by using a powder-free scannable impression material, the dentist–author makes it possible for her laboratory partner Gold Dust Dental Lab to eliminate a step in fabrication and hence removes at least one opportunity for inaccuracy. If she used a conventional impression material and sent the impression to the laboratory, the technicians could either pour their own molds using a scannable impression materials and then scan them, or apply powder to the dentist’s impression so it will reflect light and allow the scanner to read the digital data. Both of these options introduce the opportunity for inaccuracy, take extra time for the technician, and increase materials costs for the laboratory. Another downside with the second option is that the powder adds mass to the impression and, hence, introduces more inaccuracy to the process (Figure 3 and Figure 4). By utilizing a powder-free scannable VPS material and digitizing the impression upfront, the dentist and laboratory can efficiently and affordably provide patients with more precisely fitting prostheses.
This article was supplied by Heraeus Kulzer.
About the Authors
Lee Ann Brady, DMD
Lee Ann Brady, DMD, is a nationally recognized educator, lecturer, and writer. She is the former Executive Vice President of Clinical Education for Spear Education and Clinical Director of the Pankey Institute. Dr. Brady is president of leeannbrady.com, which offers continuing education workshops, seminars, and online content. She maintains a private practice in Glendale, Arizona and is the clinical editor of the Seattle Study Club Journal and a guest faculty member for The Pankey Institute.
Jenn Janicki is chief operating officer of Gold Dust Dental Laboratory in Tempe, Arizona. Ms. Janicki has 17 years’ experience in the dental industry. After earning honorable distinction in business development for large corporations, she has incorporated those skills and strategies into the fundamental success of a leading all-ceramic laboratory.