Case #4

By: Romali Kamat, D.D.S.

An 87-year-old female presented with a chief concern of “I have a bridge that has lasted 40 years, but it needs to be replaced. I moved from McKinney, TX, and the doctor there suggested I get implants.” Her concern was a PFM FPD 8-X-10-X-12 with non-restorable decay at 10 and 12. The patient had existing implant restorations at 3-X-5, 13, 14, 18, 19, 20, 22 and 29-X-31 (Figure 1 and 2).

The patient refused any type of removable prosthesis. Two fixed treatment options were presented to her: (1) an implant-supported FPD from 8-X-10-X-12, or (2) a full-arch implant-supported fixed detachable denture (a.k.a. “hybrid”). She was primarily concerned with esthetics and the remaining lifespan of her three remaining natural maxillary teeth 6, 7, and 15 (which were endodontically treated and crowned). The patient chose the hybrid option, which included retaining her existing implants, and adding two anterior immediate implants. The challenge of retaining and utilizing her existing maxillary implants while achieving adequate prosthetic space for the prosthesis was able to be addressed as implant crowns 13 and 14 were already 12mm in height. Implant crown #3 was only 8mm in height, so a #4 implant was planned in the surgical guide if prototypes failed. The advantages of keeping her existing implants included reduced cost to the patient, reduced load on newly placed implants, and more comfort during the first 3 months of healing post-surgery.

Each appointment thereafter consisted of identifying the existing implants. For the practitioner, this work is often difficult - drilling through implant crowns and abutments of unknown years hoping not to damage a screw; for the patient this requires a lot of patience in the chair and losing teeth without plans for temporary replacement due to her finances. Implant #3 was identified as 3i external hex 5.0mm platform, #5 was a Nobel external hex 4.0mm platform, #13 Astra EV 4.2mm, and #14 Astra EV 4.2mm. Due to the original placement of the implant and subsequent years of bone loss, the platform of 5 was too coronal in the patient’s smile line, and thus, was planned for removal.

The beauty of retaining implants is also appreciated during prosthetically-guided surgical planning. With support from prosthodontic faculty, Dr. Roberta Wright, the idea to create a surgical guide supported by her existing implants blossomed. Tony Walker from Express Dental Lab and Dr. Sara Amin from ITX Pros worked with me to design and fabricate the guide. The intraoral pre-op scan was obtained via iTero5D scanner with Dess scanbodies placed on each implant, making sure to capture the existing dentition and the hard palate. The guide design started with a tissue and tooth-supported guide with Astra drilling sleeves at 4, 7 and 10 for the placement of implants after extraction. At the lab, the hard palate was removed, and temporary copings were luted to the guide from a printed model after digital model trimming representing where bone reduction was needed for adequate prosthetic space (Figure 3). Therefore, an additional bone reduction guide was not needed as the implant-supported surgical guide would seat fully only when adequate bone was removed.

On the day of surgery, teeth 6, 7, 9, 10, 12 and 15 were extracted, implant #5 was removed, and roughly 5mm of ostectomy was completed in the anterior to implants 3 and 13. The guide was seated to engage into implants at 3, 13, and 14 and was secured in place with prosthetic screws. Then, using a fully-guided surgical approach, Astra PrimeTaper implants 4.2 x 11mm and 3.6 x 11mm were placed at sites 7 and 10 respectively. Once primary stability was achieved, multi-unit abutments were placed using 1.5mm gingival height abutments with a 0⁰ at 7 and 17⁰ at 10 (Figure 4).

Another advantage of retaining some of her existing implants was the ease of immediate conversion and loading. A full-arch acrylic prototype was printed to seat at existing implants 3, 13, and 14 with pre-planned windows left in the prosthesis to conventionally pick-up implants at 7 and 10 chairside. The conversion prosthesis was finished and polished with a convex intaglio surface, and placed intraorally. Radiography was made to ensure complete seating of the prosthesis. Access holes were temporarily sealed, and occlusion was controlled.

Post-operative instructions included a list of liquid/soft foods the patient may eat for the next 3 months, hygiene instructions on using a water flosser, and management of swelling and discomfort. The patient was pleased with the outcome both functionally and esthetically. (Figure 5).

About The Author

Dr. Romali Kamat is originally from the small town of Alice, Texas. She received her bachelor’s degree in Integrative Biology at the University of California, Berkeley. She then attended the University of Texas Health Science Center at San Antonio College of Dentistry where she received her doctorate. After completing the AEGD residency at University of Oklahoma College of Dentistry, she will be an associate general dentist with her partner, Dr. Cristobal Urrutia, at 7 to 7 Dental & Orthodontics in San Antonio, Texas. In the future, she hopes to open her own private practice, but for now enjoys spending weekends walking with Cristobal and her miniature schnauzer, Kiki.