subperiosteal implants
Osseointegration of subperiosteal implant via guided tissue regeneration. A pilot study.
Full text link : https://pubmed.ncbi.nlm.nih.gov/7578790/
Osseointegration of subperiosteal implant via guided tissue regeneration. A pilot study
1. Scientific Reference
- Study Title: Osseointegration of subperiosteal implant via guided tissue regeneration. A pilot study
- Authors: E. Hjorting-Hansen, M. Helbo, M. Aaboe, K. Gotfredsen, E.M. Pinholt
- Scientific Journal: Clinical Oral Implants Research
- Year of Publication: 1995
- DOI: 10.1034/j.1600-0501.1995.060303.x
2. Scientific Background
Subperiosteal implants have historically represented a solution intended for the stabilization of removable prostheses in patients presenting significant bone resorption. However, their development has been limited by difficulties related to their biological integration and long-term stability. The authors recall that the clinical outcomes observed with these devices have often been affected by insufficient integration between the implant structure and the underlying bone.
At the same time, advances in Guided Tissue Regeneration (GTR) techniques have opened new perspectives for promoting bone formation in various surgical situations. In this context, the idea of combining a subperiosteal implant with a regenerative membrane in order to stimulate new bone formation around the implant represents an experimental approach aimed at improving its biological anchorage.
This preclinical study is therefore part of an exploratory approach seeking to determine whether guided bone regeneration can contribute to the osseointegration of an implant structure positioned on the surface of the bone.
3. Study Objective
The primary objective of this study was to evaluate the possibility of obtaining osseointegration of a titanium subperiosteal implant through the use of a guided tissue regeneration membrane.
The researchers sought to create favorable conditions for bone formation between the bone surface and a customized implant framework placed in a subperiosteal position, in order to observe whether this newly formed bone could lead to biological integration of the implant.
4. Methodology
This study is presented as a preclinical pilot study conducted on an animal model.
Four adult Copenhagen White rabbits were included. Bone impressions were taken from the tibia to individually manufacture cast titanium implant frameworks. Each animal received a subperiosteal implant on both tibiae.
One side served as a control with direct fixation of the implant to the bone. On the experimental side, an expanded polytetrafluoroethylene (e-PTFE) membrane was positioned above the implant to create a space intended for bone regeneration.
The observation period was 12 weeks. Evaluations included radiographic examination and histological analysis after sacrifice of the animals.
5. Main Results
Healing was described as favorable in all animals throughout the study period.
Radiographic analysis of the experimental sites revealed the presence of a thin radiopaque zone beneath the membranes, compatible with bone formation around the implant structure. In contrast, the control sites did not show comparable radiographic signs of new bone formation.
Histological observations demonstrated important differences between the two experimental conditions. In the control sites, bone integration appeared limited to certain peripheral areas, while a considerable proportion of the structure remained surrounded by connective tissue.
In the membrane-treated sites, the implants appeared to be much more extensively surrounded by bone tissue. The authors describe variable but present osseointegration throughout all sections examined. No histological section demonstrated an implant completely surrounded by connective tissue. The implant was frequently in direct contact with newly formed bone.
The authors nevertheless report that the spaces generated beneath the membrane also contained substantial marrow cavities and that the amount of newly formed bone tissue remained limited.
6. Clinical Analysis
This study represents an early attempt to combine the principles of guided bone regeneration with the design of subperiosteal implants. At a time when osseointegrated endosseous implants were progressively becoming the therapeutic reference, the authors sought to solve one of the main challenges of subperiosteal implants: their durable integration with bone.
The obtained results suggest that a regenerative membrane can modify the biological environment around an implant positioned on the bone surface and promote a certain degree of bone formation in contact with it. The value of the work lies less in the quantity of bone produced than in the experimental demonstration of the possibility of obtaining bone-implant contact on a subperiosteal structure.
However, several factors require cautious interpretation. The observations concern an animal model limited to four subjects and a relatively short observation period. Furthermore, the authors themselves emphasize that the generated bone exhibited a delicate architecture and that the space created beneath the membrane was largely occupied by marrow spaces.
Thus, this study does not demonstrate the clinical efficacy of an osseointegrated subperiosteal implant in humans, but provides an interesting experimental proof of concept regarding the use of guided tissue regeneration in the field of implant reconstruction.
7. Clinical Applications
The results of this study may be of interest in the fields of bone reconstruction and complex implant rehabilitation, particularly when it is necessary to improve the interface between an implant structure and bone tissue.
The authors consider the possibility of eventually combining concepts derived from endosseous implants and subperiosteal implants in order to develop devices with improved biological integration.
However, the study provides no human clinical data allowing this approach to be recommended in routine practice. Its principal value lies in understanding the biological mechanisms of osseointegration and in exploring new implant reconstruction strategies using guided bone regeneration.
8. Level of Evidence, Limitations and Transparency
This publication corresponds to a preclinical pilot study conducted in animals.
The level of evidence should be considered low within the hierarchy of clinical evidence, since the results concern neither human patients nor a large-scale comparative study.
Among the main methodological limitations are:
- the small sample size (four rabbits);
- the experimental nature of the model;
- a follow-up duration limited to 12 weeks;
- the absence of human clinical data;
- the absence of long-term evaluation.
No conflicts of interest are explicitly declared in the information provided. The authors nevertheless mention that certain membranes and fixation systems were supplied by manufacturers, without it being possible to conclude that a conflict of interest existed on the basis of the available information.
9. Key Points of the Study
- Study Type: Preclinical animal pilot study.
- Level of Evidence: Low level of evidence.
- Population or Number of Studies Analyzed: 4 rabbits.
- Number of Patients or Implants: Not precisely specified in the provided information.
- Follow-up Duration: 12 weeks.
- Primary Outcome Evaluated: Bone formation and osseointegration of a subperiosteal implant associated with a regenerative membrane.
- Main Result: Greater osseointegration was observed in membrane-covered sites than in control sites.
- Scientific Conclusion: Bone formation around a customized subperiosteal implant appears possible through guided tissue regeneration.
- Potential Limitations: Animal model, small sample size and limited follow-up.
10. Scientific Impact
This publication occupies a distinctive place in the history of implantology by exploring an alternative approach aimed at improving the biological integration of subperiosteal implants.
Its principal contribution lies in the experimental demonstration that an environment created through guided tissue regeneration can promote a closer interaction between a titanium implant framework and the underlying bone. At the time of its publication, this approach represented an original extension of bone regeneration concepts already being investigated for the repair of bone defects.
Although the available data remain limited and do not support a direct clinical application, the study contributes to the ongoing discussion regarding bone reconstruction strategies and the evolution of customized implants. It also illustrates the potential value of approaches combining patient-specific design with biological control of bone healing.
11. Editorial Conclusion
This 1995 pilot study provides early experimental evidence suggesting that guided tissue regeneration may promote the osseointegration of customized subperiosteal implant structures. The results observed in rabbits demonstrated greater bone formation in contact with the implant than that observed at control sites.
Given the preclinical nature of the study and its small sample size, these findings should be interpreted as a demonstration of biological feasibility rather than as a clinical validation of the technique. Nevertheless, the work represents an important milestone in the exploration of biologically enhanced subperiosteal implant concepts and contributes to the scientific foundations underlying modern approaches to customized implant reconstruction.
