It’s Time to Go Digital for Impressions
Marc Geissberger, DDS, MA, BS, CPT
Digital equipment exclusively developed to replace conventional impressions has existed for well over a decade. The original units were somewhat slow, and image acquisition was laborious. Additionally, the capture devices were heavy, and the equipment was clumsy and difficult to maneuver. Fortunately, those days are long gone. Today’s digital impression technology represents significant improvements in image-capture quality and speed as well as accuracy that far surpasses that of conventional impression techniques.
While many practitioners have introduced practice management software, digital radiographs, and caries detection technology into their practices, far fewer have begun using digital scanning equipment. Integrating digital scanning into general practice can be accomplished simply and seamlessly with minimal training. Now may be the time for your practice to make the transition. This article will discuss the many benefits of digital impression technology.
1. Patient Satisfaction
One of the most common complaints from patients is the claustrophobia they have had with conventional impression techniques. Many patients report this to be the most difficult portion of the crown experience.1 For patients with a substantial gag response, the final impression is a major source of stress. Digital impressions make this a much easier procedure for patients and can be completed faster than conventional means. Additionally, breaks can be introduced during the process with no deleterious effect on the clinical outcome and can alleviate stress for patients.
2. Stress-Free Impression-Making
With conventional impression techniques, working time is always tied to setting time.2 While fast-setting materials are generally preferred, they inherently come with short working time, which dramatically increases the stress level to the dental team. One key benefit to digital impression-making is the ability to start and stop as needed. If moisture becomes an issue, the practitioner can stop, re-establish a dry field, and begin where he or she left off. This ensures that each impression can be captured successfully on the first try.
3. Improved Quality
Digital scanning eliminates the inherent inaccuracy introduced by conventional elastomeric impression materials and stone that can produce excessive expansion if water/powder ratios are not managed precisely. The accuracy of scanners has been well established as being more precise when compared to conventional impressions and corresponding stone casts.3
4. Improved Productivity
Originally, the time it took to capture a digital impression was greater than the time required to capture a conventional impression. This was largely due to the capture software and the processor speed of the digital impressions. Digital scanning equipment has become increasingly faster at capturing digital impressions. True Definition (3M, www.3M.com) and TRIOS® (3Shape, www.3shape.com) are examples of systems that can capture a final impression in approximately 1 minute,4 which represents a significant time-savings when compared to traditional techniques.
5. Improved Skills and Outcomes
Digital impression technologies allow practitioners to evaluate their work on a whole new level. Having the ability to rotate a preparation and review margin design at very high magnification gives practitioners the ability to alter preparations and rescan as needed. This added benefit allows modifications to be made to preparations that would have been largely overlooked with conventional techniques. This can dramatically improve clinical outcomes for patients.
6. Better Delivery Time
With the improved accuracy of digital impressions, practitioners will experience far shorter time needed to deliver restorations,5 representing an improvement in practice productivity through better time management.
7. Reduction in Inventory
Digital impression technology allows clinicians to eliminate a large portion of inventory used for conventional impression techniques. Items such as impression syringes, stock trays, and different viscosities and setting times of impression material no longer need to be stocked. This not only profoundly affects revolving overhead, but will also eliminate accumulation of hazardous landfill material, making dental practices “greener.”
8. Enhanced Communication
The digital platform allows clinicians to open new levels of communication with the dental laboratory. They can quickly scan and send digital impressions to their technicians and seek input and feedback efficiently. This opens lines of communication rarely available when using conventional techniques. The clinician may be able to seek laboratory input on a case prior to dismissing the patient.
9. Potential to Expand to Digital Crown Design and Fabrication
Most digital scanning equipment introduced to the marketplace in the past 2 years has been developed on an “open platform.”6 These systems allow practitioners to expand from simple digital impression capturing to include CAD (computer-assisted design) of restorations to be manufactured by a third party or by adding CAM (computer-assisted manufacturing) to their practice, producing restorations in house.
Clinical Integration
A patient presented seeking esthetic enhancement of her maxillary arch, with her chief concern being several failing and unesthetic crowns on this arch (Figure 1). Many existing restorations presented with open and over-contoured margins and decay. The tentative treatment plan was a maxillary arch reconstruction using a combination of porcelain-fused-to-metal crowns and Lava™ (3M) layered zirconia restorations. In total, 14 restorations were treatment planned.
After preparations were completed on the 14 units, the daunting task of capturing a flawless impression was undertaken. The clinician felt the probability of packing 28 cords and successfully capturing acceptable impressions using a conventional approach was low. In this case, an iTero® (Align Technology, Inc., www.itero.com) digital scanner was used. The advantage of using a digital scanner is that the clinician can pack cords on a few teeth, capture those preparations, and move on to the next few teeth, capturing the impression in stages. If needed, the impression could even be done over two appointments.
After the digital impression was captured, it was automatically transmitted to the dental laboratory to begin the lab phase of the process. Figure 2 through Figure 4 show the laboratory phase of the reconstruction. In this case, the lab chose to fabricate the restorations using a model. Modeless options now exist that can further streamline the process. Figure 5 shows the successful post-treatment outcome.
Conclusion
The benefits of introducing digital impression technology to a dental practice are numerous and must be considered when clinicians are contemplating their next digital upgrade. Rather than thinking of digital impressions as “just another way to take impressions,” practitioners should view digital impressioning as the next evolution in the pursuit of improved patient outcomes and satisfaction.
Disclosure
Marc Geissberger, DDS, MA, BS, CPT, is a stock shareholder at 3M.
References
1. Joda T, Brägger U. Patient-centered outcomes comparing digital and conventional implant impression procedures: a randomized crossover trial. Clin Oral Implants Res. 2015;1-5. doi: 10.1111/clr.12600.
2. Hatzi P, Tzakis M, Eliades G. Setting characteristics of vinyl-polysiloxane interocclusal recording materials. Dent Mater. 2012;28(7):783-791.
3. Burgess J, Lawson N, Robles A. Comparing digital and conventional impressions. Inside Dentistry. 2013;9(11):68-74.
4. Kim J, Park JM, Kim M, et al. Comparison of experience curves between two 3-dimensional intraoral scanners. J Prosthet Dent. 2016 Apr 6. doi: 10.1016/j.prosdent.2015.12.018. [Epub ahead of print]
5. Su TS, Sun J. Comparison of marginal and internal fit of 3-unit ceramic fixed dental prostheses made with either a conventional or digital impression. J Prosthet Dent. 2016. doi: 10.1016/j.prosdent.2016.01.018.
6. Kachalia PR, Geissberger MJ. Dentistry a la carte: in-office CAD/CAM technology. J Calif Dent Assoc. 2010;38(5):323-330.
About the Author
Marc Geissberger, DDS, MA, BS, CPT
Professor and Chair
Department of Integrated Reconstructive Dental Sciences
University of the Pacific School of Dentistry
San Francisco, California
