Taking a Digital Approach
Confidently offer more conservative treatment with increased accuracy
Stephen D. Poss, DDS, Diplomate ACSDD
An otherwise healthy 68-year-old male patient presented with a loose bridge across teeth Nos. 5 through 12 (Figure 1). In particular, teeth Nos. 5 and 7 were causing him significant pain. The bridge was supported by abutments on teeth Nos. 5, 7, 10 and 12. After conducting a clinical examination, including radiographs, it was discovered that the abutments on teeth Nos. 5 and 7 had failed due to decay. This was the third time that the patient’s bridge had failed. Considering that teeth Nos. 5 and 7 would need to be extracted, possible treatment options included either a removable partial denture or dental implants. Teeth Nos. 10 through 12 were in good condition, and considering the financial concerns of the patient, it was determined that the best treatment plan would be to section the bridge between teeth Nos. 9 and 10, extract teeth Nos. 5 and 7, and place implants in the extraction sites of teeth Nos. 5, 6, 8, and 9 with bone augmentation around the extraction sites of Nos. 5 and 7. A partial denture would be placed immediately, followed by definitive restorations after 3 months of healing.
An initial digital impression of the existing bridge was captured with a CS 3600 intraoral scanner (Carestream Dental) and used to fabricate a temporary partial denture for teeth Nos. 5 through 9. To evaluate the bone and plan the angulation for the future implants, a cone-beam computed tomography (CBCT) scan was taken using the CS 9300 system (Carestream Dental). A collaborating periodontist, David Meister, DMD, Periodontal and Implant Associates of Middle Tennessee, was consulted for the fabrication of a surgical stent utilizing the 3-dimensional data from the digital impression and the CBCT scan (Figure 2). Once the stent was returned from the lab, the patient was scheduled for surgery.
After administration of a local anesthetic, the bridge was cut between tooth No. 9 and tooth No. 10. The decay associated with supporting teeth Nos. 5 and 7 was so great that they broke and fell out along with the bridge. However, their root tips remained and still required extraction (Figure 3). The stent was then used to punch out the tissue (Figure 4), allowing for a conservative, flapless approach, and the implant sites were scalloped out to accommodate the ovate pontics.
Once the stent was snapped back into position (Figure 5), the sites of teeth Nos. 5, 6, 8, and 9 were drilled in preparation for implants. The implants were placed with the stent and tightened to initial stability (Figure 6). Following this, bone was placed to augment the extraction sites of teeth Nos. 5 and 7, healing caps were placed (Figure 7), and the partial was seated (Figure 8). The definitive crowns will be placed in the future after the implants are allowed to heal.
Because this patient had already suffered through two failing bridges, he was discouraged to receive the diagnosis of a third failure. However, the choice of a surgical stent to place dental implants allowed for a conservative treatment plan that would be more accurate and require less healing time. In addition, the decision to replace only half of the bridge also made the procedure more affordable for the patient, which led him to accept the treatment plan with confidence. With the aid of the stent, four implants were placed in minutes (the entire surgery took less than an hour), without having to disturb the tissue through a more aggressive, traditional gingival flap. This process results in less patient discomfort and more rapid healing.
Utilizing the intraoral scanner and CBCT system when planning the case increased confidence in its success, as digital methods result in more accurate appliances and positioning of implants. The highly detailed 3D images captured by the CS 9300 confirmed the quantity and quality of the bone and, accordingly, allowed the case to be better planned. Furthermore, the digital impressions taken with the CS 3600 were not only more accurate, but also led to faster turnaround times with the lab for the fabrication of both the surgical stent and the temporary partial. Because it eliminates the need for traditional alginate and trays, the CS 3600 will also play a key role in the future when fabricating and placing the crowns.
The open architecture of the intraoral scanner’s .STL files and the CBCT system’s DICOM files made it easier to communicate with the collaborating periodontist and lab. By taking a digital approach, including the ease of acquiring impressions, the 3D views of the bone, and the increased accuracy of fabrication and placement, the patient received his partial and was on a path to healing that would only take a couple of weeks.
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About the Author
Stephen D. Poss, DDS, Diplomate ACSDD