An in vitro comparison of the computerized tomography/CAD-CAM and direct bone impression techniques for subperiosteal implant model generation

A new concept for implant-borne dental rehabilitation; how to overcome the biological weak-spot of conventional dental implants?

Background

Every endosseous dental implant is dependent on an adequate amount and quality of peri-implant hard and soft tissues and their fully functional interaction. The dental implant could fail in cases of insufficient bone and soft tissues or due to a violation of the soft to hard tissues to implant shoulder interface with arising of a secondary bone loss.

Method

To overcome this biological weak-spot, we designed a new implant that allows for multi vector endosseous anchorage around the individual underlying bone, which has to be scanned by computed tomography (CT) or Cone beam CT (CBCT) technique to allow for planning the implant. We developed a workflow to digitally engineer this customized implant made up of two planning steps. First, the implant posts are designed by prosthodontic-driven backward planning, and a wireframe-style framework is designed on the individual bony surface of the recipient site. Next, the two pieces are digitally fused and manufactured as a single piece implant using the SLM technique (selective laser melting) and titanium-alloy-powder.

Results

Preoperative FEM-stress-test of the individual implant is possible before it is inserted sterile in an out-patient procedure.

Conclusion

Unlike any other historical or current dental implant protocol, our newly developed “individual patient solutions dental” follows the principle of a fully functional and rigid osteosynthesis technology and offers a quick solution for an implant-borne dental rehabilitation in difficult conditions of soft and hard tissues.

The use of prefabricated titanium tissue abutments for the construction of a maxillary subperiosteal implant

This article presents a bimodal procedure for a patient with an implant-supported fixed partial denture (FP2 class of Misch) where endosteal implants (EOIs) and a subperiosteal implant (SPI) were indicated in different sections of the same arch. In edentulous patients, heterogeneous bone volume and density may be encountered in different regions of the same arch. When the available bone is favorable, the use of EOIs is simpler and less time consuming. An SPI is indicated when the available bone is severely resorbed, as in the type I division C, type II divisions C and D, and type III divisions C and D. The main advantage of the described combined technique is that it offers an alternative to invasive surgeries such as iliac crest bone grafts or various surgical augmentation procedures. The second advantage is the very brief healing period after insertion of the SPI before prosthetic loading. Planning, design, laboratory construction, surgical application, and prosthetic rehabilitation for bimodal implant treatment are described. Prefabricated titanium tissue abutments are used in the fabrication of the posts of the anterior titanium SPI. Titanium tissue abutments are placed in the waxup stage of the SPI before the casting of the titanium SPI. Posterior fixtures are EOIs. An anterior SPI with 4 posts and 4 posterior EOIs provides a combination of support for the screw-retained fixed maxillary denture of Misch's FP2.

A descriptive 18-year retrospective review of subperiosteal implants for patients with severely atrophied edentulous mandibles

STATEMENT OF PROBLEM

Fabricating dentures for the patient with severe mandibular atrophy can be a challenge for both the dentist and patient. Subperiosteal implants with a mandibular overdenture may be a solution for the atrophic mandible.

PURPOSE

The purpose of this retrospective study was to review the survival of mandibular subperiosteal implants placed at the University of Missouri Kansas City (UMKC) School of Dentistry Graduate Prosthodontics program between 1982 and 2000.

MATERIAL AND METHODS

Forty subperiosteal implants were placed in atrophic mandibles of 40 patients (33 women, 7 men) between 1982 and 2000. The age range of the patients was 47 to 80 years of age at time of placement (mean=62 years). Each patient was reviewed clinically by an author (DJM). Manual depression and lifting of the framework were used to evaluate the stability of the implant. Additionally, the implants were observed for any movement. Each patient was questioned for pain or discomfort. Each patient was examined for observable inflammation and intraoral exposure of the framework and questioned as to whether the implant had satisfied the patient and met the patient's expectations.

RESULTS

Thirty-nine of the 40 original patients were recalled in 2000. One patient had died. Fourteen patients had implants for over 10 years, 12 patients had implants between 5 and 10 years, and 12 patients had implants for less than 5 years (mean time of implant service=8 years). Thirty-eight patients had the implant in place with no sign of inflammation or mobility, 1 patient with diabetes had inflammation around one of the struts. All patients were wearing their prostheses, and there was no sign of exposed implant framework for any patient. All patients reported a high level of satisfaction with the implant.

CONCLUSIONS

Within the limitations of this study, the mandibular implants placed at UMKC were still functioning, and all patients denied any discomfort or pain from the prostheses. Patients reported they were comfortable and able to function with the implant-supported prosthesis.