Long-Term Survival of Subperiosteal Implants: Meta-Analysis and Current Status of Subperiosteal Implants for Dental Rehabilitation

Nils-Claudius Gellrich, Philippe Korn, Michael Neuhaus, Fritjof Lentge, Philipp Jehn, Björn Rahlf

Full text link: https://pubmed.ncbi.nlm.nih.gov/39578012/ 

Long-Term Survival of Subperiosteal Implants: A Meta-Analysis and Contemporary Overview of Subperiosteal Implants for Dental Rehabilitation

1. Scientific Reference

• Study Title: Long-Term Survival of Subperiosteal Implants: A Meta-Analysis and Contemporary Overview of Subperiosteal Implants for Dental Rehabilitation
• Authors: Nils-Claudius Gellrich, Philippe Korn, Michael Neuhaus, Fritjof Lentge, Philipp Jehn, Björn Rahlf
• Journal: Oral and Maxillofacial Surgery Clinics of North America
• Year of Publication: 2025
• DOI: https://doi.org/10.1016/j.coms.2024.09.006

2. Scientific Background

The management of severe jaw atrophy remains one of the most challenging areas in implant dentistry and oral rehabilitation. While endosseous dental implants have become the standard treatment for edentulous patients, some clinical situations still present anatomical limitations that complicate conventional implant placement or require extensive reconstructive procedures.

Subperiosteal implants were originally developed as an alternative approach for patients with insufficient bone volume. Despite early clinical use, their popularity declined over time due to biological and mechanical complications associated with historical designs. Recent advances in digital workflows, three-dimensional imaging, CAD/CAM technologies, prosthetically driven planning, and additive manufacturing have renewed interest in patient-specific subperiosteal implants.

This publication examines how modern customized frameworks differ from their historical predecessors and explores the available evidence regarding their long-term clinical performance. The topic is particularly relevant for complex implant rehabilitation, maxillofacial reconstruction, and patients with advanced bone loss who may not be suitable candidates for extensive grafting procedures.

3. Study Objective

The primary objective of this study was to evaluate the long-term survival of subperiosteal implants through a review and meta-analytical assessment of the available literature.

The authors also sought to compare historical subperiosteal implant concepts with modern CAD/CAM-designed patient-specific implants and to identify technical and prosthetic factors that may influence clinical outcomes in contemporary dental rehabilitation.

4. Methodology

A comprehensive MEDLINE search was conducted using combinations of keywords related to subperiosteal implants, implant survival, long-term outcomes, CAD/CAM technology, customization, and patient-specific implant design.

Following screening and removal of duplicate publications, 57 studies were included in the final analysis. Among these:

• 12 publications provided information regarding the long-term success of historical subperiosteal implants.
• 1 publication reported longer-term clinical outcomes for screw-fixated CAD/CAM subperiosteal implants.
• 36 publications focused primarily on technical aspects such as implant design, manufacturing methods, fixation protocols, and prosthetic reconstruction concepts.

The review assessed survival outcomes as well as design characteristics, fixation strategies, prosthetic approaches, and manufacturing techniques associated with both historical and modern implant generations.

5. Main Findings

The review highlights substantial differences between traditional subperiosteal implants and modern digitally designed patient-specific systems.

Historical implants generally relied on adaptation of the framework to the bone surface without rigid fixation. Although several studies reported acceptable survival rates over time, complications including infections, implant instability, and progressive bone resorption were also documented.

In contrast, contemporary CAD/CAM subperiosteal implants incorporate rigid screw fixation, prosthetically driven digital planning, and customized framework design. According to the authors, these developments represent a fundamental shift rather than a simple evolution of historical concepts.

A major finding of the review is the current lack of robust long-term evidence for modern CAD/CAM implants. No validated 20-year follow-up studies are currently available, and the first 10-year clinical outcomes are expected in the near future.

The authors further emphasize the importance of implant fixation, framework geometry, screw distribution, soft-tissue management, and prosthetic design as critical factors influencing treatment success.

6. Clinical Analysis

One of the most valuable contributions of this article is its clear distinction between historical and contemporary subperiosteal implant concepts. These two approaches are frequently grouped together in the literature despite major differences in biomechanics, fixation principles, and digital planning workflows.

The review suggests that many of the complications historically associated with subperiosteal implants may have been linked to inadequate fixation and design limitations rather than to the concept itself. Modern patient-specific implants are engineered through a fully digital workflow and are rigidly anchored using multiple fixation screws, creating a substantially different biomechanical environment.

The study also highlights the often-underestimated role of soft-tissue management. The authors argue that successful rehabilitation depends not only on available bone volume but also on the ability to establish stable and functional soft-tissue compartments around implant posts and prosthetic components.

From a clinical perspective, these findings support consideration of customized subperiosteal implants as a potential treatment option in highly challenging cases involving severe maxillary atrophy, post-ablative defects, or situations where extensive reconstructive surgery is not feasible.

Nevertheless, clinicians should remain cautious. The available evidence remains limited, particularly regarding long-term outcomes, and most modern reports involve relatively short follow-up periods and case-based evidence.

7. Clinical Applications

The findings may be particularly relevant in the following situations:

• Severe maxillary or mandibular atrophy.
• Full-arch implant rehabilitation in edentulous patients.
• Complex maxillofacial reconstruction cases.
• Post-oncologic rehabilitation following ablative surgery.
• Patients unwilling or unable to undergo microvascular bone reconstruction.
• Digital implant planning and CAD/CAM-based workflows.
• Customized implant-supported prosthetic rehabilitation.
• Anatomical situations where conventional implant placement is difficult or unpredictable.

The article emphasizes that successful implementation requires integration of surgical planning, digital design, fixation strategy, prosthetic engineering, and soft-tissue management.

8. Level of Evidence, Limitations, and Transparency

This publication is best categorized as a literature review with meta-analytical evaluation and technical analysis of available evidence.

The overall level of evidence should be interpreted cautiously. While historical implants have longer follow-up data available, contemporary CAD/CAM subperiosteal implants are currently supported mainly by case series, retrospective reports, and observational studies.

An important limitation identified by the authors is the absence of long-term clinical studies evaluating modern patient-specific designs beyond approximately one decade.

Regarding transparency, the authors state that no financial support was received for preparation of the article. They disclose receiving speaker honoraria from DePuy Synthes, Brainlab AG, and KLS Martin Group.

9. Key Study Highlights

• Study Type: Literature review with meta-analytical assessment.
• Level of Evidence: Moderate to low for contemporary CAD/CAM implants.
• Studies Included: 57 publications.
• Patient/Implant Numbers: Variable across included studies.
• Follow-up Duration: Variable according to publication.
• Primary Outcome: Long-term survival of subperiosteal implants.
• Main Finding: Modern CAD/CAM subperiosteal implants should not be considered equivalent to historical designs.
• Scientific Conclusion: Rigid fixation and patient-specific digital planning appear to be key determinants of successful rehabilitation.
• Potential Limitations: Limited long-term evidence and heterogeneity among available studies.

10. Scientific Impact

This review provides an important reassessment of subperiosteal implant therapy within the context of modern digital implantology. Rather than presenting contemporary systems as a continuation of historical designs, the authors argue that they represent a fundamentally different treatment category supported by advances in imaging, engineering, and manufacturing technologies.

The article contributes to the growing body of literature exploring alternatives to extensive bone grafting and complex reconstructive procedures in patients with severe anatomical deficiencies. It also highlights the need for greater standardization in implant design principles and fixation protocols.

Perhaps most importantly, the review identifies a significant evidence gap. While early and medium-term outcomes appear encouraging in selected clinical situations, long-term validation remains necessary before definitive conclusions regarding durability and predictability can be drawn.

As such, this publication serves both as a summary of current knowledge and as a roadmap for future research in customized implant rehabilitation.

11. Editorial Conclusion

This review demonstrates that modern CAD/CAM subperiosteal implants have evolved far beyond their historical predecessors through the integration of digital planning, patient-specific engineering, and rigid fixation strategies. The available evidence suggests potential value in managing severe atrophy and complex rehabilitation scenarios where conventional implant approaches may be limited. However, the current literature remains constrained by a lack of long-term clinical data. Further prospective studies with extended follow-up are needed to determine the true durability and clinical predictability of these emerging implant solutions.