INTRODUCTION
Today, an increasing number of dental practices are transitioning to a digital workflow. From digital radiographs and intraoral photographs to completely digital patient records inclusive of oral care history and insurance records, many digital processes are now commonplace throughout the dental office. However, to fully maximize the benefits of a digital dental workflow among all contributors to a patient’s care—including dentists, front office staff, collaborating specialists, and dental laboratory teams—other information should also be captured and transferred digitally. Among this information are impressions, models, restoration designs, and fabrication data, all of which can have their foundations in digital intraoral scanner images.
Digital intraoral scanners optically acquire images of tooth structure and soft-tissue morphology—similar to how a camera takes a photograph—through a wand-like scanning device. The scanning device tip emits either laser, structured light, or light-emitting diode light to enable the capture of information in regard to what’s being scanned, which is ultimately used to create digital 3-D images.1 Intraoral scanners can be used to capture images of a patient’s natural teeth, preparations, traditional impressions, or stone models.2
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| Figure 1. The preoperative view of the fractured mandibular right first molar (tooth No. 30). | Figure 2. The pre-op radiograph of tooth No. 30 also revealed recurrent caries beneath the existing amalgam restoration. |
Once the information is in a digital format, it can become a part of a patient’s records; used when submitting dental insurance claims; shared among treatment team members and the dental laboratory team; and, of course, used for fabricating restorations and other treatment components.3,4 In fact, stand-alone intraoral scanners are a cost-effective first step into the world of digital dentistry, as they provide dentists with the convenience and accuracy of digital impressions that can be quickly shared with laboratories for fabricating restorations.5,6 In such a digital workflow, dentists use an intraoral scanner in lieu of traditional impression trays and materials to capture the details of a patient’s preoperative condition and tooth preparation. Then, rather than sending physical impressions and models to the laboratory via a mail carrier or delivery service, the dentist can electronically transfer the intraoral scans to the laboratory of his or her choice.
By eliminating the time-consuming and tedious manual procedures historically associated with traditional physical impressions, digital intraoral scanners contribute to greater efficiency and comfort during restorative appointments.7 Additionally, greater accuracy can be achieved because intraoral scanners reduce the likelihood of errors caused by material deformation or by the operatory with impression techniques.5,6,8
What’s important to note, however, is that a dentist’s ability to easily use the scanner and then transfer intraoral scans to his or her laboratory team, and to have the laboratory be able to use the scans, is dependent upon the scanner’s architecture. Intraoral scanner architecture types include open, with the ability to send and receive information from different manufacturers’ systems; closed, with the ability to use only information from the same system and/or manufacturer; or semi-open, with the ability to use some information from another system or manufacturer.4,9 An open architecture intraoral scanner is ideal since it enables dentists to use the scans with any equipment (such as a CAD/CAM milling unit) from any manufacturer as well as easily share the scanned images with their laboratory teams and/or colleagues.
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| Figure 3. An accurate and detailed intraoral scan of the preparations was taken (Aadva IOS 100 Scanner [GC America]) in lieu of taking traditional impressions. | Figure 4. Intraoral photographs of the preparation of tooth No. 30 were also taken. |
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| Figure 5. Photographs of the buccal bite view of the preparation were taken to ensure the creation of a proper occlusion in the final restoration. | Figure 6. The same buccal bite perspective was also captured digitally via an intraoral scan using the Aadva IOS 100 Scanner. |
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| Figure 7. Intraoral photographs were taken of the opposing teeth in the maxillary arch. | Figure 8. The opposing teeth in the maxillary arch were also digitally scanned using the intraoral scanner. |
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| Figure 9. View of the completed bis-acryl provisional restoration (TEMPSMART [GC America]). | Figure 10. The retracted occlusal view of the provisional restoration on tooth No. 30. |
Consider a Digital Workflow Using a Stand-Alone Scanner
For dentists looking to embark on a journey to a more digital clinical workflow, a recently introduced, stand-alone intraoral scanner system (Aadva IOS 100 Scanner [GC America]) epitomizes digital dentistry made easy. With an ergonomic design, calibration-free handpiece, and accurate scans, the Aadva IOS scanner enables dentists to incorporate an intuitive digital workflow into their practices. Furthermore, its open architecture and STL format allows the clinician to maximize its use with other technologies, including in-office patient record systems.
Similar to traditional impressions, the innovative optical technology of the Aadva IOS scanner captures details of hard and soft tissues, but in a simpler, faster, and more precise manner. However, unlike with traditional physical impressions, Aadva IOS scans enable verification of the preparation, definition of margin lines, evaluation of the bite registration, and the creation of 3-D models. The simulated model can then be used to create indirect restorations, such as veneers, inlays, onlays, single crowns, and fixed partial dentures (bridges) of up to 4 units.
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| Figure 11. The intraoral scans for the case were reviewed prior to being sent electronically to the laboratory team. | Figure 12. The preparation margins for tooth No. 30 were clearly identified and marked, which would be essential for the laboratory team when milling the zirconia full-coverage restoration. |
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| Figure 13. A digital work order for a full-coverage zirconia crown for tooth No. 30 was completed, and the presence of attached intraoral scans was indicated. | Figure 14. With the Aadva IOS system, the work order could be exported for digital/electronic transfer to the laboratory team in a variety of ways, such as via the cloud using the Aadva Data Service Platform. |
Additionally, unlike with other intraoral scanners, the Aadva IOS scanner technology can identify existing restorations, interproximal regions, and undercuts without the need or extra time required to apply a powder spray. The elimination of contrast powder spray—combined with the compact, small, and patient-friendly handpiece—translates to greater patient comfort during impression scanning procedures.
Once the Aadva IOS scanner has captured the intraoral impression, the system’s 19-in touchscreen provides clear graphics for diagnostic acuity, while its adjustable arm accommodates a range of positions to ensure maximal clinician and patient visualization and comfort. Because the handpiece cradle is heated, an automatic anti-fog feature ensures clear scans.
The system has a small mobile-cart footprint, enabling it to be moved easily from operatory to operatory, thus eliminating the need for multiple scanners. The locking lever and brake pad ensure safety and stability while in use, and the system’s round and smooth surfaces facilitate the ease of cleaning of all its touch surfaces and component parts for optimal infection control.
The following case presentation describes the use of Aadva IOS 100 scanner in the treatment of a patient who required a posterior full-coverage zirconia restoration.
CASE REPORT
Diagnosis and Treatment Planning
A patient presented with a fracture and recurrent decay beneath an existing amalgam restoration in the mandibular right first molar (tooth No. 30) (Figures 1 and 2). Pre-op photographs were taken as part of a thorough examination and shown to the patient to help explain the condition and potential treatment options.
The treatment options discussed with the patient included removing the existing amalgam and decay, followed by either placing a zirconia full-coverage crown restoration, or a large direct composite restoration. It was explained to the patient that the latter option was not considered a long-lasting alternative based upon the position of the tooth in the arch and the amount of natural tooth structure missing. Therefore, the patient consented to a full-coverage zirconia crown.
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| Figure 15. At the dental lab, a digital model was created based upon the intraoral scans for use in designing the full-coverage crown. | Figure 16. The digitally designed restoration was then virtually articulated on a digital model against the opposing arch to verify the occlusal scheme. |
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| Figure 17. A view of the crown after milling and before sintering the zirconia. | Figure 18. A view of the zirconia crown restoration, after sintering. |
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| Figure 19. The postoperative view of the definitive zirconia crown (Ottawa Zirconia Translucent [Ottawa Dental Laboratory]) immediately following cementation. |
Preparation and Provisionalization
In anticipation of creating a chairside bis-acryl provisional restoration, a pre-op vinyl polysiloxane (VPS) impression (Silginat [Kettenbach LP]) was made of the arch with the tooth to be restored. The tooth was then prepared, and the Aadva IOS intraoral scanner was used to scan the preparations in lieu of taking traditional physical impressions (Figure 3). An intraoral occlusal-view photograph of the preparation was taken (Figure 4), as well as a buccal-view photo (Figure 5) and an intraoral scan of the bite (Figure 6). Additionally, the opposing teeth in the maxillary arch were photographed (Figure 7) and also digitally scanned (Figure 8) to ensure that proper occlusion could be replicated in the definitive restoration.
A waxup was then made using the pre-op physical impression, and, from that, a silicone matrix (Sil-Tech [Ivoclar Vivadent]) was made for use in creating a direct provisional restoration. The silicone matrix was loaded with a dual-cured bis-acryl provisional material (TEMPSMART [GC America]) (Figure 9) and seated over the prepared tooth. The material was allowed to set, after which the matrix and provisional were removed from the mouth. The provisional (Figure 10) was trimmed and polished and then temporarily cemented into place using a zinc-oxide (non-eugenol) provisional cement (GC TEMP ADVANTAGE [GC America]).
Digital Workflow and Communication With the Dental Lab Team
After the patient was dismissed, the intraoral scans for the case that would be sent electronically to the laboratory team were reviewed (Figure 11). Additionally, the preparation scan of tooth No. 30 was inspected, and care was taken to identitify and mark the margins of the preparation (Figure 12). Clearly identified margins would be essential for the laboratory team when designing and milling the full-coverage zirconia restoration.
The digital workflow continued by completing a digital work order that stated the request for a full-coverage anatomic zirconia crown on tooth No. 30 (Figure 13). The work order also indicated that the intraoral scans were attached.
The work order was then exported for digital/electronic transfer to the laboratory team at Ottawa Dental Lab (Ottawa, Ill) (Figure 14). With the Aadva IOS system, a variety of transfer methods are possible: network (ie, internal private network), USB, and GC Aadva DSP (Data Services Platform). The latter transfer method allows dentists to securely transfer their prescription files to their dental laboratory team via the cloud.
Once the laboratory team received the digital impression and bite scans, a digital model and wax-up of the proposed full-coverage zirconia restoration was rendered (Figure 15). This enabled digital design and articulation of the restoration prior to milling (Figure 16). The laboratory team also printed a 3-D model of the preparation for use after milling to try on the restoration and to confirm accurate fit, contacts, contour, etc (Figures 17 and 18).
Cementation Appointment
At the cementation appointment, the bis-acryl provisional restoration was removed and the preparation was cleaned with a chlorhexidine paste (Consepsis Scrub [Ultradent Products]) and then rinsed with water. Next, the zirconia crown (Ottawa Zirconia Translucent [Ottawa Dental Laboratory]) was tried in to confirm the integrity of the margins. The inside of the zirconia crown restoration was then washed with a generic bleach solution, rinsed, and dried. The internal aspect of the crown was primed (G-Multi PRIMER [GC America]) and then set aside.
The preparation was etched for 3 seconds using 35% phosphoric acid (Selective HV Etch W/BAC [BISCO Dental Products]), then rinsed thoroughly with water. A universal, eighth-generation adhesive bonding agent with a dual-cure activator (G-Premio BOND [GC America]) was then applied to the preparation and light cured (SmartLite [Dentsply Sirona]) for 20 seconds. A dual-cure adhesive resin cement (G-CEM LinkForce [GC America]) was placed into the crown, and then the restoration was seated completely onto the preparation. Next, the restoration was tack cured for 5 seconds using the curing light from the buccal aspect and then 5 seconds from the lingual aspect. A curette was then used to easily remove any excess cement from the margins. The occlusion was verified and adjusted as required, and the patient was dismissed (Figure 19).
Among the benefits realized in the course of treating this patient by using this stand-alone intraoral scanner technology were accuracy, reduced chair time, and greater patient comfort.
CLOSING COMMENTS
When dentists are ready to embrace the promises of a digital workflow, incorporating a stand-alone intraoral scanner to replace the time-consuming and tedious manual procedures associated with traditional physical impressions can be a great way to start. For many restorative procedures, intraoral scanners contribute to greater efficiency, accuracy, and precision, as well as improved comfort for the patient.10 Although there are many intraoral scanner options to choose from, it behooves dentists to select an open-architecture technology capable of connecting and operating with other equipment and systems in their practices, as well as connecting with their laboratories, and colleagues. In the author’s opinion and experience, the Aadva IOS system represents an easy-to-use, ergonomic, and hassle-free innovation for introducing a digital workflow into any practice.
Acknowledgment
The author wishes to acknowledge and thank the team at Ottawa Dental Laboratory in Ottawa, Ill.
References
- Birnbaum NS, Aaronson HB. Digital dental impression systems. Inside Dentistry. 2011;7:84-90.
- Stein JM. Stand-alone scanning systems simplify intraoral digital impressioning. Inside Dentistry. 2012;8:66-68.
- Zandparsa R. Digital imaging and fabrication. Dent Clin North Am. 2014;58:135-158.
- Att W, Girard M. Digital workflow in reconstructive dentistry. In: Ferencz JL, Silva N, Navarro JM, eds. High-Strength Ceramics: Interdisciplinary Perspectives. Chicago, IL: Quintessence Publishing; 2014:260-277.
- Burgess JO, Lawson NC, Robles A. Comparing digital and conventional impressions: assessing the accuracy, efficiency, and value of today’s systems. Inside Dentistry. 2013;9:68-74.
- Seelbach P, Brueckel C, Wöstmann B. Accuracy of digital and conventional impression techniques and workflow. Clin Oral Investig. 2013;17:1759-1764.
- Patzelt SB, Lamprinos C, Stampf S, et al. The time efficiency of intraoral scanners: an in vitro comparative study. J Am Dent Assoc. 2014;145:542-551.
- Patzelt SB, Bishti S, Stampf S, et al. Accuracy of computer-aided design/computer-aided manufacturing-generated dental casts based on intraoral scanner data. J Am Dent Assoc. 2014;145:1133-1140.
- Bunek SS, Brown C, Yakas ME. The evolving impressions of digital dentistry: how CAD/CAM technology continues to drive innovation. Inside Dentistry. 2014;10:35-39.
- Takeuchi Y, Koizumi H, Furuchi M, et al. Use of digital impression systems with intraoral scanners for fabricating restorations and fixed dental prostheses. J Oral Sci. 2018;60:1-7.
Dr. Simos received his DDS degree at Chicago’s Loyola University. He maintains private practices in Bolingbrook and Ottawa, Ill. He is the founder and president of the Allstar Smiles Learning Center and client facility in Bolingbrook, where he teaches postgraduate courses on a variety of clinical topics, including cosmetic dentistry, occlusion, and comprehensive restorative dentistry. Dr. Simos is an internationally recognized lecturer and leader in cosmetic and restorative dentistry and is listed as one of Dentistry Today’s Leaders in Continuing Education. He can be reached via email at cmesmile50@gmail.com, via the website allstarsmiles.com, or via the Twitter handle @allstarlc1.
Disclosure: Dr. Simos reports no disclosures.
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