Additively Manufactured Titanium Subperiosteal Implants: A Long-Term Retrospective Clinical Evaluation of 10 Patients with Severe Mandibular Atrophy

Jan Łoginoff, Agata Majos, Marcin Elgalal

Full text link: https://pubmed.ncbi.nlm.nih.gov/41109674/

Additively Manufactured Titanium Subperiosteal Implants: A Long-Term Retrospective Clinical Evaluation of 10 Patients with Severe Mandibular Atrophy

1. Scientific Reference

• Study Title: Additively Manufactured Titanium Subperiosteal Implants: A Long-Term Retrospective Clinical Evaluation of 10 Patients with Severe Mandibular Atrophy
• Authors: Jan Łoginoff, Agata Majos, Marcin Elgalal
• Journal: Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology
• Year of Publication: 2025
• DOI: 10.1016/j.jormas.2025.102621

2. Scientific Background

Advanced mandibular atrophy remains one of the greatest challenges in implant dentistry and oral rehabilitation. In patients with extensive alveolar bone loss, conventional endosseous dental implants may no longer be feasible without extensive bone augmentation procedures. Consequently, alternative treatment strategies continue to attract increasing clinical interest.

The combination of three-dimensional imaging, CAD/CAM digital planning, and additive manufacturing has renewed attention toward patient-specific subperiosteal implants. By producing implants that closely match the individual’s mandibular anatomy, these digital workflows aim to improve surgical precision while offering a reconstructive option for patients with limited therapeutic alternatives. This study contributes to the growing body of evidence evaluating the long-term clinical performance of custom-made titanium subperiosteal implants manufactured using direct metal laser sintering (DMLS), with particular emphasis on implant survival, biological complications, and long-term stability in severely atrophic mandibles.

3. Study Objective

The purpose of this retrospective investigation was to assess the long-term clinical and radiographic performance of patient-specific titanium subperiosteal implants manufactured by direct metal laser sintering (DMLS) in individuals presenting with severe mandibular atrophy. The authors specifically evaluated implant survival, postoperative complications, and long-term bone stability following treatment.

4. Methodology

This retrospective clinical study included 10 patients diagnosed with Cawood and Howell Class IV–VI mandibular atrophy. Each patient received a custom-designed titanium subperiosteal implant developed from computed tomography (CT) imaging and manufactured using DMLS technology.

Postoperative clinical and radiographic follow-up was performed to evaluate implant survival, biological complications, and the stability of the supporting bone over time. The maximum reported follow-up period reached 12 years. The available abstract does not provide additional information regarding surgical protocols, prosthetic rehabilitation, radiographic assessment methods, or statistical analyses.

5. Main Findings

At the end of the observation period, 7 of the 10 implants remained functional and clinically stable, corresponding to an overall implant survival rate of 70%.

All patients experienced early postoperative edema and pain, which were successfully managed with conservative treatment. According to the authors, these early postoperative events did not compromise implant function.

Late biological complications developed in three patients, ultimately requiring implant removal. The reported causes included bone resorption and granulation tissue formation. Despite these failures, the majority of implants maintained long-term clinical stability throughout the follow-up period, suggesting that patient-specific DMLS-manufactured subperiosteal implants can provide durable rehabilitation in selected cases of severe mandibular atrophy.

6. Clinical Analysis

This study provides valuable long-term clinical observations regarding a treatment option intended for one of the most demanding situations in implant dentistry: rehabilitation of patients with severe mandibular atrophy who cannot receive conventional endosseous implants.

Rather than evaluating a new implant design alone, the investigation reflects the clinical application of a fully digital workflow combining CT-based planning, CAD/CAM engineering, and additive titanium manufacturing. Such an approach enables individualized implant fabrication that conforms closely to each patient’s anatomy, potentially expanding treatment possibilities in highly compromised cases.

The reported outcomes indicate that long-term implant function can be achieved in a majority of treated patients. Nevertheless, the occurrence of late biological complications leading to implant removal demonstrates that this treatment is not free from long-term risk. Bone resorption and soft tissue complications remain important considerations during prolonged follow-up.

Because of its retrospective design and limited sample size, the study should be interpreted cautiously. It does not establish superiority over alternative reconstructive techniques, nor does it define optimal patient selection criteria. Instead, it contributes meaningful long-term clinical evidence supporting the feasibility of customized subperiosteal implants in carefully selected patients while highlighting the importance of continuous postoperative monitoring.

7. Clinical Applications

The findings are particularly relevant for patients with severe mandibular atrophy (Cawood and Howell Classes IV–VI) who are unsuitable candidates for conventional endosseous implant placement.

The study illustrates the potential role of patient-specific subperiosteal implants within a fully digital workflow incorporating CT imaging, CAD/CAM design, and additive titanium manufacturing. These implants may represent a reconstructive option in complex implant rehabilitation when conventional approaches are contraindicated. The reported outcomes also emphasize the need for long-term clinical and radiographic surveillance to identify biological complications that may develop years after treatment. The available data do not include comparisons with bone grafting procedures or other advanced rehabilitation techniques.

8. Level of Evidence, Limitations, and Transparency

This publication represents a retrospective clinical study, providing a moderate-to-low level of clinical evidence compared with prospective controlled clinical trials.

Several methodological limitations should be considered, including the small sample size (10 patients), the retrospective design, and the absence of a control group. These factors restrict the generalizability of the findings and preclude direct comparisons with alternative treatment modalities.

The abstract does not report detailed statistical analyses, nor does it mention funding sources or conflicts of interest. Therefore, no conclusions can be drawn regarding potential author affiliations or financial relationships based on the information provided.

9. Key Study Highlights

• Study design: Retrospective clinical study
• Level of evidence: Moderate to low
• Study population: 10 patients with Cawood and Howell Class IV–VI mandibular atrophy
• Number of implants: 10 patient-specific titanium subperiosteal implants
• Maximum follow-up: Up to 12 years
• Primary outcome: Implant survival, clinical stability, biological complications, and bone stability
• Main result: Overall implant survival rate of 70%, with seven implants remaining functional throughout follow-up
• Scientific conclusion: DMLS-manufactured patient-specific titanium subperiosteal implants appear to be a promising treatment option for selected patients with severe mandibular atrophy when conventional implant therapy is contraindicated.
• Limitations: Small sample size, retrospective design, no control group, and no comparison with alternative rehabilitation techniques.

10. Scientific Impact

This study adds meaningful long-term clinical data to the evolving literature on digitally manufactured patient-specific subperiosteal implants. While additive manufacturing has substantially improved the precision and customization of implant fabrication, long-term clinical evidence remains relatively limited.

The extended follow-up presented in this investigation provides valuable insight into the durability of these implants in a highly challenging patient population. Rather than establishing definitive clinical recommendations, the findings support the feasibility of integrating digital planning and additive manufacturing into the management of severe mandibular atrophy while acknowledging that biological complications may still occur over time.

The study also underscores the need for larger prospective investigations with comparative designs to better define indications, long-term success predictors, and the relative performance of customized subperiosteal implants compared with other reconstructive implant rehabilitation strategies.

11. Editorial Conclusion

This retrospective clinical evaluation provides encouraging long-term evidence regarding the use of additively manufactured, patient-specific titanium subperiosteal implants for the rehabilitation of severely atrophic mandibles. Although biological complications requiring implant removal occurred in a subset of patients, most implants remained clinically functional during prolonged follow-up. Given the limited sample size and observational design, these findings should be interpreted cautiously. Nevertheless, the study contributes valuable clinical evidence supporting the continued investigation of digitally designed subperiosteal implants as a potential treatment option for carefully selected patients with advanced mandibular atrophy.