CAD/CAM subperiosteal implants in Australia. Case report

1. Scientific Reference

• Study Title: CAD/CAM Subperiosteal Implants in Australia. Case Report
• Author: James Edward Fischer
• Scientific Journal: Australian Dental Journal
• Year of Publication: 1993
• DOI: Not specified in the provided materials.

2. Scientific Background

Managing fully edentulous patients with severe mandibular bone resorption remains one of the most challenging situations in implant dentistry. In cases where residual bone volume is limited, conventional implant-supported rehabilitation may not always be feasible, prompting consideration of alternative treatment approaches.

Subperiosteal implants have historically been used as a treatment option for patients with advanced jaw atrophy. Traditional fabrication techniques required an initial surgical procedure to expose the underlying bone and obtain a direct bone impression before manufacturing the implant framework. This process increased treatment complexity and surgical burden.

The development of computed tomography (CT) imaging and computer-aided design/computer-aided manufacturing (CAD/CAM) technologies introduced new possibilities for creating patient-specific implant frameworks based on three-dimensional anatomical data. The present case report explores the application of these digital technologies to subperiosteal implant fabrication, with the aim of eliminating the preliminary surgical stage traditionally required for implant construction.

3. Study Objective

The purpose of this case report was to describe the use of a CAD/CAM-generated subperiosteal implant fabricated from CT-derived anatomical data in a fully edentulous patient with a severely resorbed mandible.

More specifically, the author sought to demonstrate a treatment workflow capable of avoiding the initial surgical procedure traditionally required to obtain a direct mandibular bone impression for subperiosteal implant fabrication.

4. Methodology

This publication is a single-patient case report.

The patient was a 50-year-old Caucasian woman who had been completely edentulous for more than twenty years and presented with significant mandibular bone resorption. Because of difficulties associated with lower denture stability, treatment with a CAD/CAM-designed subperiosteal implant was planned.

A CT scan of the mandible was performed using a dedicated stabilization device to minimize movement during image acquisition. Thirty-one tomographic slices were obtained at intervals of 1.5 mm.

The imaging data were transferred to a computer system capable of reconstructing a three-dimensional model of the mandible. A robotic milling process was subsequently used to generate a physical replica of the mandibular anatomy. The implant framework was then designed on a duplicate model, manufactured, and prepared for surgical insertion.

The duration of postoperative follow-up was not specified in the information provided.

5. Main Results

The CAD/CAM workflow successfully enabled fabrication of a customized subperiosteal implant before surgery, based entirely on CT-derived anatomical information.

During the surgical procedure, the mandibular bone was exposed and the implant framework was positioned. According to the author, the fit of the framework was carefully assessed, and particulate hydroxyapatite was used in areas where augmentation was considered necessary.

Following wound closure and healing, a provisional snap-on denture was delivered. The postoperative recovery period was reported to be uneventful.

The principal finding of this report is the technical feasibility of producing a patient-specific subperiosteal implant from CT imaging and CAD/CAM manufacturing techniques, thereby eliminating the need for the traditional first-stage surgical bone impression procedure.

6. Clinical Analysis

This publication represents an early example of digital workflow integration within implant dentistry and oral rehabilitation. Although commonplace today, three-dimensional imaging, virtual planning, and patient-specific implant manufacturing were still emerging concepts at the time this report was published.

The most clinically relevant aspect of the study is the replacement of a surgical bone impression procedure with a CT-based digital reconstruction process. From a treatment perspective, this approach aimed to reduce the number of surgical interventions required for fabrication of a subperiosteal implant.

For patients presenting with severe mandibular atrophy and long-term difficulties with conventional dentures, the described workflow illustrates a potential method for creating a custom implant framework while avoiding one surgical stage.

However, caution is required when interpreting the findings. The report involves only a single patient and provides no long-term data regarding implant survival, prosthetic performance, biological complications, mechanical complications, or patient-reported outcomes.

Consequently, the study should be viewed primarily as a proof of technical feasibility rather than evidence of clinical superiority. Its value lies in demonstrating the practical application of CT-guided CAD/CAM manufacturing within the field of implant-supported rehabilitation.

7. Clinical Applications

The findings described in this report may be relevant in several clinical situations.

The primary application concerns fully edentulous patients with severe mandibular resorption for whom conventional prosthetic solutions provide inadequate function or stability.

The study also highlights the potential role of digital technologies in implant planning and custom implant fabrication. By utilizing CT-derived anatomical information, clinicians may be able to develop individualized treatment solutions tailored to complex anatomical conditions.

Nevertheless, the available data do not allow conclusions regarding long-term clinical effectiveness, predictability, or applicability to broader patient populations. Further research would be required to evaluate these aspects.

8. Level of Evidence, Limitations and Transparency

This publication represents a case report, which corresponds to a low level of clinical evidence.

Its principal limitation is the inclusion of a single patient without a control group or comparison with alternative treatment methods. The report is descriptive in nature and does not provide statistical analysis.

No long-term follow-up outcomes are reported in the available material, preventing assessment of implant longevity, biological behavior, or prosthetic success over time.

The provided article does not mention conflicts of interest, financial disclosures, or manufacturer affiliations.

The results should therefore be interpreted as a demonstration of technical feasibility rather than definitive evidence supporting routine clinical implementation.

9. Key Study Points

• Study type: Case report.
• Level of evidence: Low.
• Population analyzed: One patient.
• Number of patients or implants: One patient; exact implant count not specified in the provided materials.
• Follow-up duration: Not specified in the provided materials.
• Primary outcome evaluated: Feasibility of CAD/CAM-designed subperiosteal implant fabrication and placement.
• Main result: Successful production and placement of a customized subperiosteal implant based on CT-derived anatomical data.
• Scientific conclusion: The described workflow demonstrates the possibility of eliminating the traditional first-stage surgical bone impression procedure.
• Potential limitations: Single case, absence of comparative analysis, and lack of long-term clinical outcomes.

10. Scientific Impact

This report occupies an important position in the historical development of digital implant dentistry. Rather than focusing on long-term clinical outcomes, it documents an early application of CT imaging and CAD/CAM technology for the design and manufacture of a patient-specific subperiosteal implant.

Its scientific contribution lies in demonstrating how digital reconstruction of skeletal anatomy can be used to replace a conventional surgical impression procedure. This concept anticipated many principles that later became central to modern digital workflows, including three-dimensional planning, customized implant manufacturing, and anatomy-driven treatment design.

Although the study does not provide evidence regarding long-term success, it illustrates a significant technological transition in implant dentistry and contributes to the evolution of personalized approaches for managing complex edentulous patients with severe jaw atrophy.

11. Editorial Conclusion

This case report describes an early application of CAD/CAM technology for the fabrication of a customized mandibular subperiosteal implant in a fully edentulous patient. While the evidence remains limited because it involves a single clinical case and lacks long-term follow-up data, the publication highlights the feasibility of integrating CT-based three-dimensional modeling into implant treatment planning. Its historical relevance lies in demonstrating how digital technologies could simplify traditional subperiosteal implant workflows and pave the way for future developments in personalized implant rehabilitation.