As a result of severe bone resorption, subperiosteal implants have been used to provide support for prostheses in edentulous patients, however with unpredictable outcomes1,2. The introduction of root form and Zygoma implants to treat edentulous severely resorbed maxillary arches have been reported with high success3-5. This modality has been considered an alternative option for extensive grafting procedures in the to compensate for the severe bone resorption negating implant placement. The aim of this report is to present a case of a failed subperiosteal maxillary implant managed with a fixed profile prosthesis supported by zygoma and root form implants using a graftless approach.
A 51 year old female presented complaining of pain and prosthesis mobility related to her maxilla. Radiographic exam revealed a failing maxillary subperiosteal implant placed to support the prosthesis associated with severe bone resorption.
A decision was made to remove the subperiosteal implant and provide a fixed profile prosthesis supported by Zygoma implants bilaterally and two axial implants placed in the premaxilla using a graftless approach due to the severe bone resorption negating conventional implant placements.
Surgery was performed under local anesthesia with intravenous sedation.A full mucoperiosteal flap was reflected and dissection was performed to expose the subperiosteal implant. After careful manipulation, the subperiosteal implant was removed completely with minimal bone removal. After further dissection, two Zygoma implants were placed on each zygoma according to the manufacture’s recommendation to provide posterior support. Then, two axial implants were placed in the premaxilla to provide anterior support.
A decision was made to immediately load the implants after achieving favorable insertion torques. Multi-unit abutments were connected to the implants and holes in the dentures were then created accordingly. The denture was connected to the implants using temporary multi-unit copings and quickset® acrylic. Palatal coverage and buccal flange was also removed. Post op panorex revealing complete seating of the multi-unit abutments and temporary cylinders.
An abutment level closed-tray impression was made using heavy and low body PVS. To verify the implant positions in the cast, a verification jig was fabricated and tried in. Next, jaw relation records were made, which replicated the previous vertical dimension of occlusion the patient had during the provisional prosthesis. The lab was then instructed to fabricate a try-in teeth setup (stage 1 try-in) using the jaw relations provided. The setup was then tried in the patient’s mouth. Extra- and intra-oral features were then evaluated. After patient approval of the teeth setup, a matrix was fabricated of the mounted setup and sent to the lab for framework fabrication. The lab then used the matrix, teeth setup, and verification jig provided to scan the cast and mill a titanium framework using CAD/CAM technology. The framework was then tried in the patient’s mouth using a one-screw test.. The final (stage 2) try-in consisted of adding the previous teeth setup (approved in the stage 1 try-in visit) on the framework (that was confirmed for passive seating earlier). After final approval, the setup and framework were sent back to the lab for processing and finishing. The lab was instructed to fabricate an ovate surface on the intaglio aspect of the prosthesis. This allows better oral hygiene measures by minimizing food accumulation underneath the dentures. After the lab processed and polished the profile prostheses, the prostheses was delivered to the patients. All screws were torqued using 15Ncm force. The access holes of the cylinders were covered using cotton pellets and temporary filling material.
Authors in this case report present a patient with severe maxillary bone resorption as a result of a failed subperiosteal implant that was managed with a fixed profile prosthesis supported by zygoma and root-form implants, immediately loaded, using a graftless approach.
1. Yanase, R. T., and R. L. Bodine. "Management of mandibular subperiosteal implant denture problems." Int. Symp. on Preprosthetic Surgery, Palm Springs, CA. 1985.
2. Albrektsson, T., et al. "The long-term efficacy of currently used dental implants: a review and proposed criteria of success." Int J Oral Maxillofac Implants 1.1 (1986): 11-25.
3. Bedrossian, Edmond, and Lambert J. Stumpel III. "Immediate stabilization at stage II of zygomatic implants: rationale and technique." The Journal of prosthetic dentistry 86.1 (2001): 10-14.
4. Bedrossian E, Stumpel III L, Beckely M, Indersano T. The zygomatic implant: preliminary data on treatment of severely resorbed maxillae. A clinical report. International Journal of Oral & Maxillofacial Implants. 2002 Nov 1;17(6).
5. Malevez, C., Abarca, M., Durdu, F., & Daelemans, P. (2004). Clinical outcome of 103 consecutive zygomatic implants: A 6-48 months follow-up study. Clinical Oral Implants Research, 15(1), 18-22.