Mechanical evaluation of a patient-specific additively manufactured subperiosteal jaw implant (AMSJI) using finite-element analysis

Additively manufactured custom-made subperiosteal implant rehabilitation for severely atrophic maxillary molar area: A technical note

Implant-prosthetic rehabilitations of severely atrophic posterior maxillary sectors currently is challenging, often requiring multiple surgeries and long rehabilitation times. Recently, graftless techniques (e.g. zygomatic, pterygoid and nasal implants) have gained popularity as they offer a reduction in rehabilitation time, aligning more closely with patient preferences but may not be feasible for sectorial rehabilitations. Subperiosteal implants, suggested for full-arch rehabilitations of atrophic maxilla, haven't been explored for sectorial rehabilitations. In this report we present the case of a patient with maxillary molar edentulism, rehabilitated with a subperiosteal implant.

Full-arch rehabilitation of severely atrophic maxilla with additively manufactured custom-made subperiosteal implants: A multicenter retrospective study

The aim of this retrospective study was to analyze a series of patients who underwent full-arch rehabilitation of the atrophic maxilla using additively manufactured subperiosteal implants, between August 2018 and January 2023, at the Universities of Sassari and Poznan. In total, 36 patients and 72 implants were included, with no implants lost during follow-up, and a success rate of 90.3%. Seven (9.7%) of the implants showed class 1 exposure. Bleeding on probing was detected in 10.4% of the abutments at 6 months, 7.9% at 1 year, 10% at 2 years, 7% at 3 years, and 11.4% at 4 years. No significant bone resorption under the abutments was detected during the whole observation period. Based on the findings from this study, additively manufactured subperiosteal implants could represent a safe and reliable technique for full-arch rehabilitation in patients with severe maxillary atrophy.

Evaluation of Clinical Success of the 3D-Printed Custom-Made Subperiosteal Implants

OBJECTIVE

The authors aim to share their experiences in subperiosteal implant applications in atrophic jaws, which have been practiced in their clinic for about 2 years, and evaluate the complications and clinical success of the implants.

MATERIAL AND METHOD

Clinical and radiologic data of 32 patients who underwent subperiosteal implantation for advanced alveolar bone loss were evaluated, but 1 patient was excluded as they smoked. Of the 31 patients included in the study, 27 were operated with the diagnosis of total tooth loss, 3 for maxillectomy and 1 for partial tooth loss. A total of 60 subperiosteal implants were placed in them. The mean follow-up period was 15 months.

RESULTS

During the operation, implant-bone adaptation problems were encountered in 11 patients, implant skeletal fracture in 1 patient, and loss of primary stabilization during mini-screw fixation in 2. Although there were no complications in the early postoperative period, biological and prosthetic complications occurred in the late postoperative period. Soft tissue retraction at various levels in 12 patients (only keratinized tissue retraction in 6 and mucosal retraction exceeding keratinized tissue in 6), soft tissue infection in 5 and oroantral fistula development in 1, mini-screw loosening in 3 were the biological complications that occurred.

CONCLUSIONS

Various complications may occur during or after the application of custom-made subperiosteal implants. However, these are manageable and can be reapplied in case of a possible implant loss, making it an important alternative, especially in atrophic jaws where endosseous dental implants cannot be applied.

Implant-prosthetic rehabilitation of the atrophic posterior mandible with additively manufactured custom-made subperiosteal implants: a cohort study

The aim of this study was to retrospectively analyse a series of patients with posterior mandibular atrophy rehabilitated with custom-made subperiosteal implants. The study included patients with severe posterior mandibular atrophy who had undergone rehabilitation with subperiosteal implants between September 2018 and August 2022 in the Maxillofacial Surgery Operative Unit of the University Hospital of Sassari. Complications and the success rate were reviewed. Data from 30 implants placed in 17 patients were included and analysed. There were no major complications during the surgeries. The main postoperative sequela was oedema, which was reported as moderate by most patients and had completely regressed within 10 days of surgery. No partial or complete exposures, infections, or loss of the implants were detected during follow-up (average follow-up 22.5 months). Control computed tomography scans, performed at 6 months and then annually in all cases, did not show significant bone loss below the abutments, displacement of the implants, or loss or loosening of the osteosynthesis screws. Subperiosteal implants may represent a safe and reliable technique for the rehabilitation of severe atrophy of the posterior mandible. Prospective studies with a long follow-up will be needed to establish the long-term results of this type of implant-prosthetic rehabilitation.

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.