Let's Get Digital by Dr. Robin Henderson

Let's Get Digital 

A fully digital workflow allows dentists to take control and exercise their creativity


by Dr. Robin Henderson


I became a dentist, likely for the same reason as many of you, by going down a path of enjoying math and science. I’ve been a dentist for more than 20 years and enjoy the creativity that I can express every day in my work—creativity that results in a better quality of life for my patients. In the past, this creativity was largely evident in direct restorative dentistry or in the planning stages, such as wax-ups, of larger indirect cases. As materials evolved and in-office CAD/CAM technology became incredibly efficient and accurate, I embraced Cerec restorations, specifically custom-designed and -stained IPS E.max. Where I once had to rely on my abilities to accurately communicate with a dental lab technician and, further, on the technician’s abilities for the final outcome, I could now add this to the list of things where creativity was more likely to triumph over disappointment.

Another thing that came with adoption of the Cerec intraoral scanner and in-office milling was the beginning of a new workflow. As this completely new digital workflow was evolving, suddenly my creativity was not just expressed in the restorations that I delivered but even more so in treatment planning. The digital workflow allows for so many opportunities to solve problems in new ways. It is not unusual to use several elements from the digital workflow to address unique patient needs. The following case shows how technology can be used to creatively drive solutions.

Case study

The hygienist detected an external invasive root resorption lesion on tooth #21 when the patient was in for periodontal maintenance (Figs. 1 and 2). A CBCT was taken after examination to determine the extent of the lesion to aid in treatment planning. Unfortunately, this particular lesion (Fig. 3) was too large to be treated and necessitated extraction.


Let's Get Digital Dental Technology
Fig. 1
Let's Get Digital Dental Technology
Fig. 2
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Fig. 3

Initially, we discussed the possibility of orthodontic treatment to close the space or an implant to replace the tooth. The patient had a good experience with an implant in the past, so she elected that option. We outlined a routine plan of extraction, time allowed for healing, implant placement, time allowed for osseointegration and then restoration of the implant.

Before the extraction of #21, we imaged the patient in Cerec Ortho, which allows for full-arch scanning and bite registration, so we could print a 3D model and use it to ultimately copy her existing tooth shape into the final implant restoration. We were not planning on a provisional; however, if this had been an anterior tooth, we would have used the 3D-printed model to make a positive pressure thermal plastic on the MiniStar for the extracted tooth to be placed into and worn as a provisional.

Having a digital impression not only makes this process more accurate than alginates, but it is also much easier and less stressful because you don’t have to worry about the stone model breaking when you take off the thermal plastic retainer. The 3D-printed models very rarely fracture, and if they do, you simply print another one. It is not unusual for patients to require more than one thermoplastic provisional during the time between the extraction and the final implant restoration, so having the ability to easily make this with no additional chair time is ideal. The digital impression and 3D-printed model are also useful in planning the implant placement and making the surgical guide.

For this patient, the extraction was straightforward. We had some concerns with her lack of keratinized tissue, but we continued to monitor it. The surprise came when preparing for implant placement and it was found that tooth #20 had moved mesially 1.5 mm, leaving a large open contact at #19–20 and not leaving enough space for an implant at #20 (Fig. 4).


Let's Get Digital Dental Technology
Fig. 4: Surprise finding of Tooth #20 moving mesial into the implant site position after the extraction of #21.


Clinical tip: Root resorption lesions
Root Resportion

We find and treat root resorption lesions frequently. Unlike caries, the patient doesn’t present with thermal or sweet sensitivity. These are asymptomatic, other than (rarely) bleeding when patients perform home care. Careful assessment of the gingival architecture is what usually leads to early detection. We are always on the lookout for an isolated area of erythematous tissue that is also frequently slightly hyperplastic in appearance and bleeds easily on provocation. In our experience, these occur almost exclusively in patients who show signs of gastric juices entering the oral cavity. When we catch these early, we have good success with removing the invaginated soft tissue and restoring with resin.

We previously used glass ionomer as a restorative material for these lesions; however, we found glass ionomer to wash out over time, necessitating replacement. With these always being in difficult locations to both access and isolate, it is not something you want to have to treat more than once! Also, in my experience, glass ionomer does not give the same smooth surface texture as resin and the tissues remain more inflamed around the GI restorations. There are new 2021 ADA CDT codes for surgical repair of root resorption lesions, depending on anterior, premolar or molar. They are D3471, D3472 or D3473, respectively.


We again revisited the option of comprehensive orthodontics, but we also discussed trying to move #20 distal with limited orthodontic movement before implant placement, which the patient elected for. To accomplish this, we imaged in Cerec Ortho (Fig. 5), made a 3D-printed model (Fig. 6) and used Ultradent Block-Out Resin in the space distal of #20 where we wanted to move the tooth into. We also disced the mesial of #20 to apply a force with an aligner (Fig. 7). We then used the Biostar Mini to fabricate an aligner over the model and had the patient wear the aligner for 10 days. When the patient was back in for evaluation of movement, the space was nearly closed (Fig. 8). Another Cerec Ortho scan was taken and the previous steps were completed to fabricate a second aligner to finish the space closure.

Let's Get Digital Dental Technology
Fig. 5: Image in Cerec Ortho of mesial movement of Tooth #20 after the extraction of #21.
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Fig. 6: Removing models from the 3D printer.
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Fig. 7: 3D-printed model blocked out and ready for aligner fabrication.
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Fig. 8: Tooth movement from fabrication of in-office aligner.


Fortunately, this was accomplished in-office very efficiently and did not delay implant treatment. We worked with a local general dentist, whose practice is focused on implants, and treatment proceeded with implant placement as planned. The patient continued to wear the aligner (Fig. 9) during osseointegration to prevent any movement of #20.

Let's Get Digital Dental Technology
Fig. 9: Aligner fabricated to prevent movement during osseointegration.


Once integrated, the implant was restored with Cerec providing same-day dentistry. My favorite aspect of Cerec digital imaging/design is how it allows for the soft-tissue emergence to be captured accurately and supported by the restoration (Figs. 10 and 11). When designing the implant restoration, Cerec software allows the user to select “gingival mask” and outline the parameters for the final restoration using the actual contours of the soft tissue (Fig. 12). This differs from the analog workflow, where it is difficult to capture the soft-tissue emergence profile and copy it into the final restoration. Cerec also allows for the design of a screw-retained hybrid abutment final restoration (Fig. 13). This is very quick to insert and eliminates the possibility of cement sepsis/implantitis while also allowing for easy retrieval. Ivoclar’s E.max is a beautiful material that is easy to work with, and the screw-access opening is nearly invisible when filled with the same shade of Ivoclar’s Tetric EvoCeram resin (Figs. 14 and 15).

Let's Get Digital Dental Technology
Fig. 10: Soft-tissue emergence.
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Fig. 11: Cerec image of soft tissue.
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Fig. 12: Capturing the soft tissue during design.
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Fig. 13: Designed E.max hybrid abutment restoration sent to the Sirona MCX mill.
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Figs. 14 and 15: Final restoration at insertion.
Let's Get Digital Dental Technology
                                                                                                    Figs. 14 and 15: Final restoration at insertion.
Conclusion

Digital dentistry allows me to take much more control over the final outcomes with greatly improved accuracy. I know that almost 50% of dentists are now using intraoral scanners, and I would encourage them to take advantage of those images. For me, although it is still demanding to get the results that I am envisioning, I find it much more fulfilling to move the whole process, from start to finish, under my control. I have found this gives the best patient experience and is least disruptive to the flow of treatment. This reduces stress, because you aren’t having to think about, “Will the restoration be back in time for an insertion appointment?” “Will the patient and I approve of the restoration/ appliance shape, shade and fit?” “Will the patient be able to return for the insertion appointment?”

The materials and technologies are ready to give predictable and excellent outcomes. I fully encourage dentists to jump in with both CAD/CAM and 3D printing. Hopefully, you will not only enjoy the improved outcomes, but you will find joy in the process of taking control and exercising your creativity in dentistry differently. For me, it has been a true experience in art and science.


Thanks to Dr. Greg Bengtson for the surgical aspects of this case.


Author Bio
Robin Henderson Dr. Robin Henderson graduated from the University of Michigan School of Dentistry and has practiced dentistry in her small hometown in the southeastern corner of the state of Washington for more than 20 years. She is active in local and state leadership in dentistry and enjoys the relationships she makes with other dentists.

Henderson has received many awards and distinctions, including Editor of the Year from the American College of Dentists in 2020 and Sedation Safety Dentist of the Year from the Dental Organization of Conscious Sedation in 2015. She was also the ADA Design Innovation Award recipient for her office remodel in 2019. Earlier in her career, Henderson was awarded the Impact Award as Outstanding Young Dentist of Washington State from the Washington Oral Health Foundation in 2008, and the Outstanding Young Dentist Award by the American College of Dentists, Washington Section, in 2006. She is a fellow of the American College of Dentists, the International College of Dentists and the Pierre Fauchard Academy

 

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