Digital impressions represent cutting-edge technology that allows dentists to create a virtual, computer-generated replica of the hard and soft tissues in the mouth using lasers and other optical scanning devices. The digital technology captures clear and highly accurate impression data in mere minutes, without the need for traditional impression materials that some patients find inconvenient and messy. Many patients find digital impressions an easier and more comfortable procedure because traditional impression materials are avoided. The impression information then is transferred to a computer and used to create restorations, often without the need for stone models.
Types of Digital Impression Technology
There are two types of digital impression technology currently available for dentists to use. One type captures the images as digital photographs, providing dentists and dental laboratories with a series of images; the other type captures images as digital video.
The images can be captured using lasers or digital scanning. Laser scanning uses concentrated light that is safe and highly precise. It captures all of the details of the teeth and gums while eliminating the patient’s need to hold unpleasant, distasteful material in his or her mouth. Digital optical scanners also are safe and highly accurate, but require teeth to be powder-coated with a special spray before scanning to ensure all parts of the impression are recorded properly.
Benefits of Digital Impressions
Digital optical impressions significantly increase efficiency, productivity and accuracy, and make it possible for dentists to e-mail the virtual impression to the laboratory, rather than send a traditional impression or stone model via regular mail. Also, digital impressions can be used to make same day dentistry restorations, thereby speeding up patient treatment and reducing the need for multiple office visits.
Other benefits of digital impressions include:
- Improved image/impression quality for better-fitting restorations
- Less chair time
- No need for distasteful impression materials that cause some patients to gag
- More comfortable, less anxious experience for patients and the dental team
- Reduced possibility of impression-taking errors and elimination of material inaccuracies for fewer restoration mistakes
- Patients tend to appreciate the new technology and state-of-the-art dental care, so they become more engaged in, and better informed about, the treatment process because they can see their impressions on-screen chairside.
- The scan of the teeth being restored, as well as the opposing teeth and bite, can be completed in just three to five minutes.
- The digital impression can be stored electronically indefinitely, which saves space, contributes to efficient recordkeeping, and supports a paper-free environment.
- Green dentistry and eco-friendly aspects include eliminating the need for disposable plastic trays and impression materials, which otherwise would be polluting landfill space; digital data is eliminated with the “delete” button.
Digital Impressions versus Traditional Impressions
Traditional impression-taking potentially involves multiple materials and occasionally more steps. Because this is a highly delicate and skilled process, it is easier to introduce error throughout any of the numerous steps involved, either from the human element, or material defects such as voids, air bubbles, or improper setting or distortions.
Digital impressioning devices eliminate much of the labor and guesswork associated with traditional impressions, and greatly reduce or eliminate errors. Simultaneously they increase time savings, both during the impression appointment and delivery of the restorations.
Digital impression devices, in most cases, eliminate the need for a return visit to the office considering the restoration can be made in the dentist’s office rather than be shipped to a laboratory. If they are not made within the dental office, in most instances the restoration can be fabricated faster due to the elimination of the working time required with traditional materials, such as stone, and shipping times.
Digital impressions prevent the need for impression materials to be placed in the mouth for upwards of five minutes during conventional techniques. This allows patients who are fearful of gagging, or claustrophobic, to be more comfortable throughout the procedure. This advanced technology has allowed many patients to get their much needed dental wok completed, which they may have avoided to prevent the use of conventional impressions.
With a physical impression, dentists rely on visual (usually with loupes) evaluations to determine if the impressions are ready to ship to the laboratory. A traditional impression is captured in the negative, making it more difficult to identify mistakes. If mistakes are identified, the dentist will need to take another impression, which means patients must undergo the procedure again, resulting in greater inconvenience and a longer appointment, as well as time lost, and added cost and material use for the dentist.
On the other hand, a digital scan enables dentists to see the “positive” image and magnify and evaluate it carefully. Errors can be corrected immediately before submitting the impression to the laboratory. With digital impressioning, when the final impression is scanned and the bite registration obtained, a virtually articulated model of the preparation (one showing how the upper and lower teeth come together) is visible on the monitor.
The system also will indicate in color if any areas of inadequate tooth reduction are present. This allows dentists to modify the amount of tooth reduction immediately to ensure that proposed restorations will fit comfortably and function properly.
If an area is missed in the initial digital scan, some digital impression systems (such as the Lava C.O.S.) allow the operator to “patch” the scan without retaking the entire impression.
With digital impression technology, additional scans can be layered onto the original virtual model for enhanced visual representation. A repeat scan to capture a revised or voided image improves the previous virtual model, without introducing new errors. Only the previously missing data is added to the model. The more scans that are added, the more accurate the virtual model; this is exactly the opposite of a traditional physical impression.
The Digital Impression Procedure: What’s Involved?
With a digital impression system, the dentist or dental assistant captures an image of a tooth/teeth preparation. With some digital impression systems, once the area to be treated is anesthetized and free of saliva and blood, the teeth are lightly dusted with specially formulated titanium dioxide powder in order to scan both arches and the bite. Other systems (such as Cadent iTero and the impression technology that accompanies the E4D Dentist System for in-office CAD/CAM restorations) allow dentists to create a powder-free, three-dimensional image of the patient’s teeth.
The digital impression typically is captured using an intraoral wand that is inserted into the patient’s mouth and moved over the surface area of the tooth or teeth. Most digital impression systems use a chairside monitor to display the impression image as it is captured.
Additionally, most digital impression systems also rely on point-and-click capture, which requires the images to be pieced together to create the final digital impression. However, the Lava C.O.S system is the only one that uses three-dimensional real-time video capture to display live images on a touch-screen monitor. This live video capture creates the final digital impressions without the need to piece together data.
It takes approximately a minute and a half to capture a digital impression of prepared teeth. An impression of the teeth in the opposite arch takes just 45 seconds.
As the dentist reviews the electronic real-time image, he or she can enlarge and manipulate it for enhanced detail to ensure that any possible mistakes are identified and corrected onscreen before sending the digital impression electronically to the dental laboratory or in-office dental CAD/CAM system. The delivery workflow will vary depending on the digital impression system the dental practice works with. Current digital impression systems available for the dental office are digital impressions only or digital chairside CAD/CAM systems.
Digital impression systems — such as Cadent iTero, 3M ESPE Lava Chairside Oral Scanner (C.O.S.) and Sirona CEREC Connect — digitally record the tooth preparations and adjacent teeth in the arch or quadrant, as well as the opposing teeth and bite registration. The data is transmitted electronically to the dental laboratory for use in restoration fabrication.
Digital chairside systems — such as D4D Technologies E4D Dentist System and Cirona CEREC Acquisition Center (AC) — also record digital impressions, but the recorded data is used within the dental office to design, mill and deliver the final restoration in one appointment for same day dentistry.
The iTero and Lava Cos are the only digital system that can be used for all types of dental restorations, including bridges, crowns, inlays and onlays, and veneers. The other digital impression systems are designed for use with select types of ceramic and composite systems.