subperiosteal implants
Radiographic Evaluation of Bone Remodeling after Additively Manufactured Subperiosteal Jaw Implantation (AMSJI) in the Maxilla: A One-Year Follow-Up Study
Full text links: https://pubmed.ncbi.nlm.nih.gov/34441837/
Radiographic Evaluation of Bone Remodeling after Additively Manufactured Subperiosteal Jaw Implantation (AMSJI) in the Maxilla: A One-Year Follow-Up Study
1. Scientific Reference
- Study Title: Radiographic Evaluation of Bone Remodeling after Additively Manufactured Subperiosteal Jaw Implantation (AMSJI) in the Maxilla: A One-Year Follow-Up Study
- Authors: Casper Van den Borre, Marco Rinaldi, Björn De Neef, Natalie A. J. Loomans, Erik Nout, Luc Van Doorne, Ignace Naert, Constantinus Politis, Hylke Schouten, Geert Klomp, Ludovic Beckers, Marshall M. Freilich, Maurice Y. Mommaerts
- Scientific Journal: Journal of Clinical Medicine
- Year of Publication: 2021
- DOI: 10.3390/jcm10163542
2. Scientific Background
The management of severe maxillary atrophy remains one of the most complex challenges in oral implantology. When the residual bone volume becomes insufficient to allow the placement of conventional endosseous implants, clinicians often need to consider bone reconstruction procedures, which may be extensive and performed in multiple stages.
The emergence of digital technologies, three-dimensional planning, and additive manufacturing has renewed interest in certain historical concepts, particularly subperiosteal implants. Custom-made subperiosteal implants manufactured by 3D printing represent an approach aimed at overcoming the limitations associated with extreme bone deficiency while enabling fixed implant-supported rehabilitation.
In this context, evaluating bone behavior around these devices represents a major issue. An important question concerns the potential impact of these structures on maxillary bone remodeling and the risk of secondary atrophy after prosthetic loading.
3. Study Objective
The primary objective of the authors was to evaluate the bone changes observed in the maxilla following rehabilitation with custom-made AMSJI (Additively Manufactured Subperiosteal Jaw Implant) subperiosteal implants.
More specifically, the study aimed to measure, through three-dimensional radiographic analysis, the phenomena of bone resorption or bone apposition at the alveolar ridge as well as at the implant support areas during the first year following functional loading.
4. Methodology
This was a prospective multicenter study conducted by the International Workgroup on AMSJI.
Fifteen patients presenting with severe maxillary atrophy classified as Cawood and Howell class V or higher were included.
Patients underwent computed tomography or CBCT examinations performed at one month (T1) and twelve months (T2) after definitive loading of the AMSJI implants. The DICOM data were segmented and subsequently superimposed using specialized software in order to compare bone volumes over time.
Predefined anatomical reference points were selected on the alveolar ridge, beneath the fixation wings, and beneath the basal framework of the implant in order to quantify bone variations.
The follow-up period analyzed was twelve months after functional rehabilitation.
5. Main Results
The fifteen included patients were followed for one year after loading of their implant-supported rehabilitation. No patient-reported discomfort or clinical complications reported by practitioners were observed between the evaluations performed at one month and twelve months.
Radiographic analysis demonstrated limited bone remodeling.
At the alveolar ridge level, the mean resorption observed across the six studied reference points was 0.26 mm (standard deviation 0.65 mm).
Beneath the fixation wings and the basal structure of the AMSJI, bone changes were even smaller, with a mean resorption of 0.088 mm (standard deviation 0.29 mm).
The authors also reported the observation of certain localized areas of bone apposition at the fixation wings, although they were unable to quantify them precisely because of titanium-related radiographic artifacts.
Overall, the results suggest substantial bone stability around the studied implants during the first year of function.
6. Clinical Analysis
This study provides interesting data regarding a therapeutic solution intended for patients presenting with advanced maxillary atrophy, a population for whom conventional implant options may be limited.
The main interest lies in the direct evaluation of bone remodeling around a custom-made subperiosteal implant designed through a digital workflow integrating CBCT, computer-aided design, and additive manufacturing. The results show that the measured bone changes remained limited during the first year following rehabilitation.
From a clinical perspective, these observations may be interpreted as a favorable signal regarding the osseous tolerance of this approach. The authors particularly emphasize the absence of significant resorption beneath the implant support areas, which constitutes a relevant element in the historical debate surrounding subperiosteal implants.
However, these data do not allow definitive conclusions regarding the long-term durability of the system. Follow-up remains limited to twelve months, and the study does not include a comparative group with other rehabilitation strategies such as bone grafting, zygomatic implants, or conventional implant protocols.
The results should therefore be interpreted as preliminary data supporting the biological feasibility of this technology rather than as definitive evidence of clinical superiority.
7. Clinical Applications
The results of this study may be particularly relevant in the context of:
- severe maxillary atrophy (Cawood and Howell class V or higher);
- implant rehabilitation of completely edentulous patients;
- CBCT-based digital implant planning;
- CAD/CAM protocols and customized additive manufacturing;
- situations in which residual bone quantity limits the placement of conventional endosseous implants;
- maxillofacial reconstruction strategies based on individualized subperiosteal implants.
However, the study does not allow the definition of exclusive clinical indications nor direct comparison of this approach with bone grafting techniques or other implant alternatives.
8. Level of Evidence, Limitations and Transparency
This publication corresponds to a prospective multicenter observational study involving fifteen patients.
The level of evidence remains moderate because of the limited sample size and the absence of a control group. The follow-up duration is also relatively short, as it is limited to one year after loading.
The authors report good reproducibility of radiographic measurements through intra- and inter-observer reliability analyses.
Several methodological limitations are discussed, notably difficulties in CBCT segmentation related to titanium artifacts, sometimes poor bone quality, and constraints inherent to three-dimensional superimposition methods.
Regarding transparency, Maurice Y. Mommaerts declares being Head of Innovation at CADskills BV, a company associated with the AMSJI concept. The other authors report no conflicts of interest.
9. Key Points of the Study
- Study Type: Prospective multicenter study
- Level of Evidence: Prospective observational study
- Population Analyzed: Patients presenting with severe maxillary atrophy
- Number of Patients: 15
- Number of Implants: Bilateral AMSJI; total number of implants not specified in the provided information
- Follow-up Duration: 12 months after loading
- Primary Outcome Evaluated: Radiographic bone remodeling around AMSJI implants
- Main Result: Mean resorption of 0.26 mm at the ridge level and 0.088 mm beneath the support areas
- Scientific Conclusion: Limited bone remodeling during the first year of function
- Potential Limitations: Small sample size, absence of a control group, follow-up limited to one year, constraints related to radiographic analysis
10. Scientific Impact
This study contributes to the emerging literature dedicated to custom-made subperiosteal implants manufactured through 3D printing. While these devices are experiencing renewed interest thanks to digital technologies, objective clinical data remain relatively limited.
The principal contribution of this work is to provide a quantitative radiographic evaluation of bone remodeling following AMSJI rehabilitation. The reported observations suggest that this approach is not associated with significant bone resorption during the first year of function.
These results reinforce the scientific interest of the AMSJI concept as a potential alternative in certain situations of advanced maxillary atrophy. They also contribute to documenting the biological interactions between the maxillary bone and next-generation custom-made subperiosteal implants.
Nevertheless, studies involving a larger number of patients and longer follow-up periods will be necessary to confirm the observed stability and clarify the role of this approach within the therapeutic armamentarium of advanced implantology.
11. Editorial Conclusion
This prospective study provides favorable preliminary clinical data regarding bone behavior around custom-made AMSJI subperiosteal implants used in patients presenting with severe maxillary atrophy. The bone changes observed after one year appear limited, both at the alveolar ridge and at the implant support areas. Despite these encouraging results, the limited sample size and restricted clinical follow-up require cautious interpretation. Longer-term follow-up studies will be necessary to confirm the biological stability of this implant rehabilitation solution.
