Replacement of a mandibular subperiosteal implant

Custom-made 3D printed subperiosteal titanium implants for the prosthetic restoration of the atrophic posterior mandible of elderly patients: a case series

Purpose

To present the application of custom-made 3D-printed subperiosteal implants for fixed prosthetic restoration of the atrophic posterior mandible of elderly patients.

Methods

Between January 2017 and June 2018, all partially edentulous patients aged over 65 years, with two or more missing teeth in the posterior atrophic mandible, and who did not want to undergo bone regenerative procedures, were included in this study. These patients were rehabilitated with custom-made subperiosteal implants, designed from cone beam computed tomography (CBCT) and fabricated in titanium by means of direct metal laser sintering (DMLS). The outcome measures were fit and stability of the implants at placement, duration of the intervention, implant survival, and early and late complications. All patients were followed for 1 year after surgery.

Results

Ten patients (four males, six females; mean age 69.6, SD ± 2.8, median 69, 95% CI 67.9–71.6) were included in the study. The fit of the implants was satisfactory, with a mean rating of 7 out of 10 (SD ± 1.6, median 7, 95% CI 6–8). Only two implants had insufficient fit, because of the presence of scattering in the CBCT; however, they were adapted to the sites during the interventions. The mean duration of the intervention was 44.3 min (SD ± 19.4, median 37, 95% CI 32.3–56.3). At the one-year follow-up, no implants were lost (survival rate 100%). One implant presented immediate postoperative complications with pain, discomfort and swelling, and two patients experienced late complications, having their provisional restorations fractured during the temporisation phase. All these complications were minor in nature, but the final complication rate amounted to 30% (three of ten patients).

Conclusions

Although this study has limits (small patient sample and short follow-up), DMLS has proven to be an effective method for fabricating accurate subperiosteal implants, with high survival rates. This may represent an alternative treatment procedure in elderly patients with a severely atrophic posterior mandible, since it allows avoidance of regenerative bone therapies. Further studies are needed to confirm these outcomes.

Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants: A Retrospective Clinical Study on 70 Patients

Purpose

To present a digital technique for the fabrication of custom-made subperiosteal implants and to report on the survival and complication rates encountered when using these fixtures.

Methods

The data used for this retrospective clinical study were derived from the medical records of five different private dental practices. Inclusion criteria were patients over the age of 60, treated with custom-made direct metal laser sintering (DMLS) titanium subperiosteal implants (Eagle-Grid®, BTK, Dueville, Vicenza) during a two-year period (2014-2015) and restored with fixed restorations; all enrolled patients needed to have complete pre- and postoperative clinical and radiographic documentation, with at least 2 years of follow-up. Exclusion criteria were smoking and bruxism. The main outcomes looked at were implant survival and complications.

Results

Seventy patients (39 males and 31 females, aged 62-79 years) who had been treated with custom-made DMLS titanium subperiosteal implants were enrolled in this study. After 2 years of follow-up, three implants were lost due to recurrent, untreatable infections; the survival rate was therefore 95.8% (67/70 implants). Four patients reported pain/discomfort/swelling after implant placement; the incidence of immediate postoperative complications was therefore 5.7% (4/70 implants). During the follow-up period, one patient suffered from recurrent infections classified as a biologic complication; the incidence of biologic complications was therefore 1.4% (1/67 surviving implants). Finally, four patients experienced prosthetic problems with their implant-supported restorations during the provisional phase (fracture of the acrylic restoration) and two patients had ceramic chipping of the definitive restoration; the incidence of prosthetic complications was therefore 8.9% (6/67 surviving implants).

Conclusions

Within the limits of the present study (limited follow-up time and low number of patients treated, retrospective design), the application of custom-made DMLS titanium subperiosteal implants showed satisfactory implant survival (95.8%) and low complication rates. Further studies are needed to confirm the positive outcomes found in this research.

Implants placed in sites of previously failed implants: a systematic review

PURPOSE

The aim of this study was to systematically review the literature on implant placement in sites of previously failed implants and to assess survival and success rates of the replacement implants to investigate the effectiveness of the procedure.

MATERIALS AND METHODS

MEDLINE and Cochrane Oral Health Group databases were used to identify articles published between 1985 and 2011. Six articles were selected for a total of 334 patients (338 implants).

RESULTS

The survival rate ranged from 71% to 100%. The survival rate for implants placed for the second time (third attempt) in the sites of previously failed implants was 83.75%. No studies included in this review reported the cumulative success rate except for the prospective one, which reported a 93.7% success rate. The main limitations of the present systematic review have been the scarce number of patients and implants in the analyzed studies and the lack of large well-designed case-control long-term trials.

CONCLUSIONS

Survival rates of implants placed in the areas of previously failed implants are low, although they should not discourage clinicians from a second or even a third attempt.

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.