subperiosteal implants
Noninvasive technique for mandibular subperiosteal implant: A preliminary report
Robert James, Phillip Boyne
Full text link : http://pubmed.ncbi.nlm.nih.gov/3514894/
Noninvasive Technique for Mandibular Subperiosteal Implant: A Preliminary Report
1. Scientific Reference
- Study Title: Noninvasive Technique for Mandibular Subperiosteal Implant: A Preliminary Report
Authors: Harold P. Truitt, D.D.S.; Robert James, D.D.S., M.S.; Philip Boyne, D.M.D., M.S.
Journal: The Journal of Prosthetic Dentistry
Year of Publication: 1986
DOI: Not specified in the available material.
2. Scientific Background
During the early development of implant dentistry, mandibular subperiosteal implants represented one of the few treatment options available for patients with severe mandibular bone resorption who were unsuitable for conventional endosseous implants. Although these custom-made frameworks demonstrated encouraging long-term clinical performance, their fabrication required a preliminary surgical procedure to expose the mandibular bone and obtain a direct impression of the osseous surface. This additional intervention increased surgical morbidity and prolonged treatment.
The present study explores an alternative approach based on computed tomography (CT) imaging and three-dimensional anatomical reconstruction. Rather than relying on direct surgical impressions, the authors investigated whether CT-derived models could accurately reproduce mandibular anatomy for the fabrication of patient-specific subperiosteal implants. At the time of publication, three-dimensional medical imaging was still in its infancy, making this work one of the earliest attempts to integrate digital imaging into implant treatment planning and custom implant manufacturing.
3. Study Objective
The primary objective of this preliminary investigation was to determine whether computed tomography could provide sufficiently accurate three-dimensional anatomical information to manufacture mandibular subperiosteal implants without performing a direct surgical impression of the bone.
The authors sought to evaluate the dimensional accuracy of CT-derived models and assess whether these models could serve as a reliable basis for fabricating implant frameworks with an acceptable anatomical fit.
4. Methodology
This publication is best classified as a technical feasibility study (preliminary technical report).
The investigation consisted of two experimental phases. Initially, a dry human skull specimen was scanned using computed tomography. Anatomical landmarks were identified, and multiple linear measurements obtained directly from the specimen were compared with corresponding measurements generated from CT images to evaluate dimensional accuracy.
In the second phase, CT data from a cadaveric mandible were used to construct a three-dimensional physical model. Based on this model, a custom mandibular subperiosteal implant was fabricated and subsequently evaluated for anatomical adaptation. Following the first prototype, technical modifications in image acquisition and model construction were implemented before producing a second implant with improved fit.
No living patients were included, and no clinical follow-up or patient outcomes were reported.
5. Principal Findings
The comparison between direct mechanical measurements and CT-derived measurements demonstrated a high degree of dimensional agreement across multiple anatomical landmarks. Differences between both measurement techniques remained minimal, suggesting that computed tomography could reproduce mandibular anatomy with a level of accuracy suitable for three-dimensional modeling.
The first implant fabricated from the reconstructed model exhibited satisfactory adaptation in several anatomical regions but revealed deficiencies, particularly in the anterior mandibular area. After optimizing both specimen positioning during scanning and the modeling process itself, the second implant demonstrated a substantially improved fit. The photographic documentation included in the publication illustrates this progressive refinement of the manufacturing technique.
Overall, the authors concluded that CT-generated three-dimensional datasets showed considerable promise for producing accurate anatomical models suitable for subperiosteal implant fabrication. However, they emphasized that the technique had not yet reached the level of accuracy required for immediate routine clinical application and required additional refinement.
6. Clinical Analysis
Although this investigation predates modern digital workflows by several decades, it represents an important milestone in the evolution of computer-assisted implant dentistry. The study demonstrates that volumetric CT imaging can provide anatomical information sufficiently accurate to support the fabrication of customized mandibular subperiosteal implants.
The principal clinical implication lies in the possibility of eliminating the preliminary surgical procedure traditionally required to obtain a direct bone impression. Such an approach could potentially reduce surgical morbidity, shorten treatment, and minimize complications associated with extensive periosteal reflection, including nerve injury or retained impression materials, as highlighted by the authors.
Nevertheless, the findings should be interpreted cautiously. The investigation remains entirely preclinical and evaluates only anatomical accuracy and implant adaptation on cadaveric specimens. It does not provide evidence regarding implant survival, prosthetic performance, biological complications, patient satisfaction, or long-term clinical outcomes.
Consequently, this study should be viewed as a proof of technical feasibility rather than evidence supporting clinical effectiveness. Its greatest contribution is demonstrating the potential of three-dimensional imaging to replace conventional impression techniques during the fabrication of customized implant frameworks.
7. Clinical Applications
Based on the available evidence, the described technique may be applicable to the digital design and fabrication of customized mandibular subperiosteal implants while avoiding direct surgical bone impressions.
The study also highlights the potential role of computed tomography in anatomical reconstruction, digital implant planning, and patient-specific implant manufacturing. However, the publication does not evaluate clinical indications such as severe mandibular atrophy, full-arch rehabilitation, or treatment outcomes in edentulous patients. Therefore, its findings should not be interpreted as validation of any specific therapeutic protocol beyond the technical feasibility demonstrated in this experimental work.
8. Level of Evidence, Limitations, and Transparency
This publication represents a preliminary technical report, corresponding to a low level of scientific evidence.
Its conclusions are based exclusively on laboratory measurements and cadaveric specimens rather than clinical patient data. The authors acknowledge that the initial models did not achieve optimal adaptation in every anatomical region and that multiple technical refinements were necessary before satisfactory accuracy could be obtained.
No conflicts of interest, commercial sponsorship, or financial disclosures are reported in the available article. Likewise, no formal discussion of study limitations is provided beyond the authors’ recognition that additional investigations and future patient studies would be required before clinical implementation.
9. Key Study Highlights
- Study design: Preliminary technical feasibility report
- Level of evidence: Low (preclinical experimental investigation)
- Study material: Dry human skull and cadaveric mandibular specimens
- Number of patients: None
- Clinical follow-up: Not reported
- Primary outcome: Dimensional accuracy of CT-derived anatomical models and implant adaptation
- Main finding: Computed tomography produced highly accurate three-dimensional anatomical data suitable for customized mandibular modeling, with implant adaptation improving after technical refinements.
- Scientific conclusion: CT-based three-dimensional reconstruction demonstrates promising potential for the noninvasive fabrication of mandibular subperiosteal implants, although additional validation is required before clinical application.
- Main limitations: Preclinical design, absence of patient outcomes, no long-term evaluation, and no comparison with alternative fabrication techniques.
10. Scientific Impact
This publication represents one of the earliest demonstrations of three-dimensional computed tomography being used for customized implant fabrication in oral and maxillofacial surgery. Although contemporary digital technologies such as CAD/CAM systems, virtual surgical planning, and additive manufacturing were not yet available, the concepts presented in this study anticipated many of the principles that now underpin modern digital implantology.
Rather than establishing clinical superiority, the study provides proof that medical imaging can generate anatomically reliable datasets suitable for manufacturing individualized implant frameworks. In retrospect, this work can be regarded as an important technological milestone that helped lay the conceptual foundation for today’s fully digital workflows in implant planning, patient-specific implant design, and computer-assisted maxillofacial reconstruction.
Its historical significance lies primarily in introducing a new direction for implant manufacturing rather than demonstrating definitive clinical effectiveness.
11. Editorial Conclusion
This preliminary technical investigation demonstrates the feasibility of using computed tomography to generate accurate three-dimensional anatomical models for the fabrication of mandibular subperiosteal implants without requiring direct surgical bone impressions. Although the study provides no clinical outcome data and remains limited to experimental validation, it represents an important milestone in the early evolution of digital implantology. From a contemporary perspective, it illustrates the origins of patient-specific digital planning and customized implant manufacturing, concepts that have since become fundamental components of modern implant and reconstructive surgery.
