Digital dentistry encompasses a wide world of convenience and new treatment options for clinicians and patients alike. With new tools—such as in-office milling systems and intraoral scanners—at our disposal, we have the ability to offer patients high-quality treatments in a fraction of the time compared to traditional methods. In many cases, this can be the key to a successful outcome for the patient.
As digital techniques have become more widespread in the industry, clinicians are continually finding new cases that are ideally treated with the use of these advanced tools. The fact that digital methods allow us to provide patients with the same high-quality restorations that they would get via traditional lab-fabrication methods in a minimal amount of time makes this type of treatment the ideal solution for patients in need of immediate and convenient services.
The case below is a prime example of one in which digital treatment was not only the preferred treatment, it was the recommended course of action.
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| Figure 1. Preoperative view of the patient’s condition as presented. Recurrent decay and a fracture had led to the failure of the existing composite resin restoration on tooth No. 30, which had, in turn, compromised the distofacial and distolingual cusps surrounding it. The patient desired a long-lasting replacement that would be strong enough to withstand the occlusal demand caused by his occasional bruxing. |
CASE REPORT
Diagnosis and Treatment Planning
A male patient in his 50s presented with good periodontal health and a history that included a few previously placed restorations and bruxism. His job was in the transportation industry, so he was constantly on the road performing demanding tasks. For this patient, time was of the essence as his schedule was not really conducive to numerous dental visits. Upon examination, it was discovered that he had a failed composite resin restoration on tooth No. 30. Recurrent decay and a fracture in the current restoration had led to the failure of the restoration; the resultant damaged tooth structure was large enough that the distofacial and distolingual cusps were compromised (Figure 1). Per the patient, this was the third time this particular restoration had required replacement. It was time to explore some other options that could lead to a more favorable outcome.
The patient was offered the following treatment options:
1. Replace the failing composite resin restoration with another direct composite restoration. The downside of this type of approach would be the expected relatively lower longevity of the restoration as compared to other restorative material options. Per the patient’s own history, this type of simple direct restoration had already failed him twice in the past, so, consequently, this was not his first choice.
2. The affected portion of the tooth could be replaced with a partial coverage restoration. Although this is an option used frequently in our office, his bruxing habit would not be beneficial to the longevity of this restoration.
3. Replace the restoration with a full-coverage monolithic crown. Due to the location, occlusal stresses, and his bruxing habit, it was decided that this would be a beneficial option for the patient.
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| Figure 2. The patient’s tooth was first built up and then prepared in accordance with the standard preparation guidelines provided for BruxZir NOW (Glidewell Laboratories) restorations. |
The patient appreciated my assessment and chose to move forward with a full-coverage, monolithic restoration. In his words, he wanted a long-lasting restoration that he “would not have to worry about” for some time to come. In addition, he wanted it completed in as timely a manner as possible.
In terms of selecting a full-coverage restoration, it is my opinion that the newer monolithic material options are an ideal combination of aesthetics and strength for situations such as this one. In particular, the occlusal demands of this patient’s case made it ideally suited to the use of a BruxZir NOW (Glidewell Laboratories) solid zirconia restoration. The recent adoption of the glidewell.io In-Office Solution (Glidewell Laboratories) in our office has made it possible for us to offer our patients BruxZir restorations in a single visit. With glidewell.io, we are able to design, mill, and deliver fully sintered zirconia crowns within an hour, allowing our patients to receive the same high-quality restorations they would receive from the dental laboratory without the need for a second visit. In this case, with the limitations on the patient’s schedule as well as his need for a strong restoration due to bruxism, creating a BruxZir restoration and delivering it within the same appointment was the ideal solution.
Clinical Protocol
To begin the process, the patient was given anesthesia, and the failed composite resin restoration was removed along with all recurrent caries. A build-up (Filtek Supreme Bulk Fill [3M]) was placed to replace the void left by the previous restoration and caries. The built-up tooth was then prepped according to the recommended guidelines for BruxZir restorations (Figures 2 and 3).
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| Figure 3. The prep design includes drafted sides, smooth surfaces, a chamfer margin, and axial and occlusal reductions of 1.5 mm. | Figure 4. Once the intraoral scan is completed, the iTero Element 2 Scanner (Align Technology) automatically transfers the data to the fastdesign.io Software (Glidewell Laboratories), which presents the clinician with an automated crown proposal based on data from millions of past cases on file at Glidewell Laboratories. Created with artificial intelligence algorithms, these automated proposals typically require little adjustment, but the clinician is free to revise the proposal as he or she sees fit. In this case, minor adjustments were made to the margin of the restoration to ensure it met the parameters that would provide the best fit. |
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| Figure 5. Other tools provided in fast-design.io allow the clinician to adjust the contacts of the proposed restoration. In this case, adjustment was not necessary, and the automatically generated contacts were simply confirmed before finalizing the crown design. | Figure 6. Occlusal view of the finalized restoration proposal, which was examined from all angles prior to milling. I was pleased with the preview provided and felt assured that the final milled restoration would be successful. |
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| Figure 7. Buccal view of the proposed restoration in place. This side view provided by the fastdesign.io Software was useful in determining that the contacts of the crown were properly set and would meet the patient’s occlusal requirements. | Figure 8. Prior to sending the crown proposal to the fastmill.io In-Office Mill (Glidewell Laboratories) for milling, its placement on the milling sprue was confirmed via the preview provided in fastdesign.io. |
Following preparation and retraction (achieved with a No. 1 braided cord with a hemostatic agent), the preparation, the working quadrant, and the opposing quadrant were scanned using the iTero Element 2 intraoral scanner (Align Technology). The prescription for the restoration was filled on the scanner and sent directly to the fastdesign.io Software and Design Station (Glidewell Laboratories) (Figures 4 to 7). Within a matter of minutes, the restoration was received and processed by the design software. Creating the proposal design itself was as simple as marking the margins, accepting the proposal generated by the software, and sending the completed proposal to the fastmill.io In-Office Mill (Glidewell Laboratories) for in-office milling.
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| Figure 9. For this case, a BruxZir NOW milling block in shade A2 was chosen to provide a close match to the patient’s existing dentition. These views illustrate the milling block inserted on the spindle before and after milling. The process took approximately 38 minutes, from sending the file from fastdesign.io to the mill through completion of the milling process. |
Prior to sending the crown proposal to the fastmill.io for milling, its placement on the milling sprue was verified via the preview provided in fastdesign.io. (Figure 8).
To complete the milling process, the appropriate milling block (in this case, an A2 BruxZir NOW block) was selected and placed into the mill. The milling process was started and completed within 38 minutes. Following the milling process, the restoration was detached from the mandrel. While polishing is not required for BruxZir NOW restorations, it was decided that, for this restoration, it would help ensure a better match to the patient’s existing dentition. The author prefers the ASAP+ Indirect Polishers (CLINICIAN’S CHOICE Dental Products) because a high luster polish can be easily achieved within a matter of minutes (Figure 9).
Delivery of the completed restoration was the final step. Cementation is a matter of preference and a matter of the retentiveness of the prep. If the prep is retentive (< 5° to 6° of taper and with 3.0 to 4.0 mm of axial wall height), a resin-modified glass ionomer cement may be used. If the prep is not deemed retentive, the use of a resin cement is advised to aid in a higher bond strength. Regardless, all chairside fabricated (in-office) zirconia restorations should be air abraded on their intaglio surfaces (25 to 50 µm aluminum oxide at 1.5 to 2 bar). (Note: For lab-fabricated restorations, this step is done in the dental lab prior to delivery to the dental office and need not be repeated at the chair.) The use of a universal primer (such as Monobond Plus [Ivoclar Vivadent]) or zirconia primer (such as Z-Prime Plus [BISCO Dental Products]) is beneficial when luting zirconia restorations with a resin cement. In this case, the restoration was abraded with 50 µm aluminum oxide at approximately 2 bar, Monobond Plus was used to prime the intaglio surface, and then the restoration was seated using a self-adhesive resin cement (RelyX Unicem 2 [3M]) (Figure 10).
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| Figure 10. The final restoration shown in place. Cementation was achieved in this case using a self-adhesive resin cement (RelyX Unicem 2 [3M]). Both the patient and I were pleased with the final outcome in terms of fit, aesthetics, and strength. As the clinician, I was comfortable in assuring the patient that the restoration would last for a long time to come. |
An evaluation of the fit, occlusion, and aesthetics was done. The patient was very happy that he was able to leave the office with a completed restoration in place and that no follow-up appointments would be required. It was a great feeling to have been able to provide this patient with the same high-quality restoration that he would have received with a traditional lab-fabricated technique in a fraction of the time and with the help of the latest digital dentistry tools.
CLOSING COMMENTS
Digital technologies are proving to be a tremendous asset to our profession. The explosive growth of the various technologies being introduced and implemented in dentistry has also made treatment more predictable and consistent. In turn, the attributes allow us, as clinicians, to provide quality care in an efficient manner. The results satisfy the needs of our most demanding patients.
Dr. Duplantis is a graduate of the University of Texas Health Science Center at San Antonio School of Dentistry. He is also a Fellow in the AGD. He serves as a key opinion leader for Glidewell Laboratories and various other dental manufacturers. In addition, he is a member of the Catapult Education Speaker’s Bureau. He has written several articles regarding digital dentistry, restorative implant dentistry, and cementation and bonding. Dr. Duplantis maintains a private practice in Fort Worth, Texas, and lectures internationally on various topics pertaining to clinical dentistry. He can be reached at drduplantis@gmail.com.
Disclosure: Dr. Duplantis is a key opinion leader for Glidewell Laboratories and CLINICIAN’S CHOICE. No honorarium was received for this article.
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