The Role of Custom-made Subperiosteal Implants for Rehabilitation of Atrophic Jaws - A Case Report

Subperiosteal implants constructed with digital technology: A systematic review

STATEMENT OF PROBLEM

Atrophied jaw is a condition where there is insufficient bone quantity and quality. Several treatment plans are available for treating atrophied jaws, including subperiosteal implants.

PURPOSE

To evaluate the spectrum of subperiosteal implants for severely atrophied jaws using digital technology.

MATERIALS AND METHODS

An electronic and manual search was conducted in the PubMed, Scopus, and Google Scholar databases. Publications of cohort studies, case series, and case reports written in English without data restrictions that reported on subperiosteal implant management of patients with severely atrophied jaws in a completely and partially edentulous population.

RESULTS

A total of 26 articles, comprising 302 cases, were analyzed. In patients with severely atrophied jaws. The success rate was 87.7%, the surviving rate was 95.3%. The most common complications were biological, such as dehiscence and framework exposure. The rates of biologic complications were 11.5%, and the rates of prosthetic problems were 5.9%.

CONCLUSIONS

Subperiosteal implants designed and constructed using digital technology are a promising treatment in the short term. Attention should be directed to decrease the biological complication. Correct designing, implanting, fixing, and patient selection and maintenance are critical for the success of the treatment. Longer prospective studies with larger population are needed to view the effect on hard and soft tissue.

Fabrication of a mandibular implant-retained overdenture using an existing subperiosteal implant: A clinical report

A 64-year-old edentulous woman with a mandibular fracture received a subperiosteal implant for fracture fixation and dental rehabilitation. However, the ball abutments were submerged by the soft tissue because they were too short. Therefore, we designed a connector to lengthen the attachment and achieve adequate stability and retention for the overdenture.

Custom-made Subperiosteal Implants: A Finite Element Analysis on Monoblock and Dual Implant Systems in Atrophic Maxilla

This study aims to investigate and compare the stress distribution, displacement, and bone loading of monoblock and dual custom-made subperiosteal implant systems in atrophic maxilla using finite element analysis (FEA). A total of 11 patients with insufficient bone tissue for conventional implant treatment were included in the study. Customized subperiosteal implant designs were generated using the 3D average models obtained from patients' computed tomography (CT) scans. Two different models were produced: a monoblock that covered the entire maxillary bone and a dual implant system where two mirror-imaged implants covered the left and right halves of the maxillary bone separately. We have calculated residual stress values formed on the implant models and jaw bone models separately. In addition, the highest displacement values formed on the implants and the highest stress values formed on abutment parts have also been observed in this study. Results showed that the stresses formed on implants that are under the mastication forces were significantly lower than the yield strength of the selected material, indicating that plastic deformation would not occur under static load. The dual implant geometry demonstrated a substantial reduction in stress compared to the monoblock structure. The highest von Mises stress values for the monoblock implants ranged from 131 MPa to 206 MPa, while those for the dual structure ranged from 124 MPa to 178 MPa. The highest residual stress values on the upper jawbone were observed in the M6 implant model, and the lowest was seen in the M1 and M3 models at 12 MPa. Displacement values under static load showed that loads on the implant would be below 0.21 mm. In conclusion, custom subperiosteal implants are a viable treatment option for patients with insufficient bone tissue for conventional implants. Dual implant systems were found to have lower stress and displacement values compared to monoblock structures, indicating a potential advantage in clinical use. However, mono implants may have benefits in cases of immediate teeth loading due to their ability to absorb and distribute occlusal forces better.

The atrophic edentulous alveolus. A preliminary study on a new generation of subperiosteal implants

The aim of this cohort case series is to present a new subperiosteal implant device that uses CAD-CAM technologies together with 3D metal printing capabilities to produce direct bone-anchored dental prosthetic solutions for the management of atrophic edentulous alveolus and jaws. The clinical experience of 21 subperiosteal devices implanted over a 4-year period is presented. The results of this study showed 14 of the 21 cases were successful (66.7%), while 7 cases had complications including exposure of the metal frame (5 cases), mobility of the device (1 case) and 1 case failed for reasons unrelated to the device. Four of the 7 cases were successfully salvaged resulting in an overall success rate of 85.7% (18 /21 cases). This study supports the use of fully customized subperiosteal jaw implants as a simple and reliable alternative for dental rehabilitation of atrophic edentulous cases which would otherwise require bone grafts for conventional fixed dental implant solutions. With more research, the clinical potential for this device is significant as it not only avoids the need for complex and lengthy reconstructive jaw surgery but also allows for the placement of immediate prosthetic teeth at the time of implantation.

Submodelling approach to screw-to-bone interaction in additively manufactured subperiosteal implant structures

Thanks to new digital technologies, complex cases of severe maxillary atrophy may now be treated with additively manufactured subperiosteal implant structures (AMSISs). However, there are few studies addressing this topic and most of them focus on the mechanical behaviour of the AMSIS itself without considering its interaction with the maxilla bone. The aim of this study is to provide a methodology based on finite element analysis (FEA) to evaluate the effect of interaction between the maxilla bone and the screws fixing the AMSIS. The mechanical performance of an AMSIS was examined via a FEA based on submodelling. Significant differences were encountered in displacements and reaction forces when bone-screw interaction was considered. Stress in the cortical layer was found to be close to the maximum strength while the trabecular layer seems to have no effect on the results; stresses in the AMSIS are lower than the fatigue stress limit. Finally, the comparison of stresses between models with and without osseointegration shows how stresses drop once osseointegration is complete. The proposed submodelling approach considerably reduces the computational effort and enables both a detailed model of the interaction between the thread of the screws and the bone and an accurate evaluation of displacement and stress fields on the interface. The results have shown that stresses in the cortical bone are highly affected by the initial geometry of the thread inside the bone, which demonstrates the importance of modelling the effect of the thread.

Virtual Surgical Planning and Customized Subperiosteal Titanium Maxillary Implant (CSTMI) for Three Dimensional Reconstruction and Dental Implants of Maxillary Defects after Oncological Resection: Case Series

Maxillectomies cause malocclusion, masticatory disorders, swallowing disorders and poor nasolabial projection, with consequent esthetic and functional sequelae. Reconstruction can be achieved with conventional approaches, such as closure of the maxillary defect by microvascular free flap surgery or prosthetic obturation. Four patients with segmental maxillary defects that had been reconstructed with customized subperiosteal titanium maxillary implants (CSTMI) through virtual surgical planning (VSP), STL models and CAD/CAM titanium mesh were included. The smallest maxillary defect was 4.1 cm and the largest defect was 9.6 cm, with an average of 7.1 cm. The reconstructed maxillary vertical dimension ranged from 9.3 mm to 17.4 mm, with a mean of 13.17 mm. The transverse dimension of the maxilla at the crestal level was attempted to be reconstructed based on the pre-excision CT scan, and these measurements ranged from 6.5 mm in the premaxilla area to 14.6 mm at the posterior level. All patients were rehabilitated with a fixed prosthesis on subperiosteal implants with good esthetic and functional results. In conclusion, we believe that customized subperiosteal titanium maxillary implants (CSTMI) are a safe alternative for maxillary defects reconstruction, allowing for simultaneous dental rehabilitation while restoring midface projection. Nonetheless, prospective and randomized trials are required with long-term follow-up, to assess its long-term performance and safety.