Clinical Behaviour and Complications of CAD-CAM Subperiosteal Implants Supporting Fixed Partial Restorations: A Scoping Review

Miguel Ruiz-Rincón, Luis Sánchez-Labrador, Tomás Beca-Campoy, Jorge Cortés-Bretón Brinkmann, Juan López-Quiles, José María Martínez-González.

Full text link: https://pubmed.ncbi.nlm.nih.gov/41688242/

Clinical Behaviour and Complications of CAD-CAM Subperiosteal Implants Supporting Fixed Partial Restorations: A Scoping Review

1. Scientific Reference

• Study title: Clinical Behaviour and Complications of CAD-CAM Subperiosteal Implants Supporting Fixed Partial Restorations: A Scoping Review.
• Authors: Miguel Ruiz-Rincón, Luis Sánchez-Labrador, Tomás Beca-Campoy, Jorge Cortés-Bretón Brinkmann, Juan López-Quiles, José María Martínez-González.
• Journal: British Journal of Oral and Maxillofacial Surgery
• Year of publication: 2026
• DOI: 10.1016/j.bjoms.2025.12.001

2. Scientific Background

Managing partially edentulous patients with severe alveolar bone atrophy remains one of the most demanding challenges in implant dentistry. Conventional endosseous implant placement frequently requires extensive bone augmentation procedures, including guided bone regeneration, sinus floor elevation, or other reconstructive techniques before implant rehabilitation can be achieved. Although these procedures are well established, they often increase surgical complexity, treatment duration, patient morbidity, and overall costs.

Recent advances in digital dentistry have renewed interest in patient-specific subperiosteal implants. Modern CAD-CAM workflows, combined with three-dimensional imaging and computer-assisted design, enable highly customized implant frameworks that conform closely to the patient’s residual bone anatomy. While these implants have been increasingly investigated for full-arch rehabilitation in severely atrophic jaws, evidence supporting their application in fixed partial restorations has remained limited. This scoping review addresses that knowledge gap by summarizing the available clinical evidence on the survival and complication profile of CAD-CAM subperiosteal implants used for partial implant-supported rehabilitation.

3. Study Objective

The purpose of this review was to evaluate the available clinical evidence regarding CAD-CAM subperiosteal implants supporting fixed partial restorations in partially edentulous patients. The authors specifically aimed to assess implant survival while documenting the biological and mechanical complications reported across the published clinical studies.

4. Methodology

This publication is a scoping review conducted in accordance with the PRISMA-ScR reporting guidelines, with its protocol registered on the Open Science Framework (OSF). The review was designed to identify and map the existing clinical evidence on CAD-CAM subperiosteal implants supporting fixed partial restorations in partially edentulous patients presenting with severe alveolar bone deficiency.

The literature search was performed across MEDLINE/PubMed, Web of Science, the Cochrane Library, and Scopus, supplemented by manual reference screening and a search of the grey literature. Eligible publications included prospective and retrospective cohort studies, controlled clinical studies, cross-sectional studies, case-control studies, and case series involving at least three patients and a minimum follow-up period of one year. Case reports, animal studies, laboratory investigations, and studies that did not separately report outcomes for partial restorations or that evaluated conventionally fabricated (non-CAD/CAM) subperiosteal implants were excluded.

Following the selection process, seven clinical studies met the inclusion criteria. Together, they included 96 patients who received 121 CAD-CAM subperiosteal implants. Implant survival served as the primary outcome measure, while biological and mechanical complications were evaluated as secondary outcomes. Reported follow-up periods ranged from one to four years, depending on the individual study.

5. Main Findings

The evidence collected across the seven studies indicates a weighted mean implant survival rate of 99.17%, with only one implant failure reported among the 121 implants evaluated. The single failure occurred in an anterior maxillary reconstruction performed in a heavy smoker, resulting in a reported survival rate of 98.77% in the maxilla and 100% in the mandible during the available follow-up periods.

Biological complications were relatively uncommon, with an overall incidence of 4.13%. Reported events included wound dehiscence, implant exposure, and isolated cases of bone loss. The only implant loss described in the review was associated with wound dehiscence that progressed to infection and implant mobility, ultimately requiring implant removal.

Mechanical complications were observed in 7.44% of implants. These consisted primarily of implant instability, fractures of provisional restorations during the provisionalization phase, and a small number of crown recementations during long-term follow-up. Importantly, postoperative discomfort such as mild pain and swelling was not classified as a complication by the authors, as these findings were considered part of the expected healing response following surgery.

6. Clinical Analysis

This scoping review provides one of the first focused evaluations of CAD-CAM subperiosteal implants used specifically for fixed partial restorations, an indication that has received considerably less attention than full-arch rehabilitation. By consolidating the available evidence, the review suggests that this patient-specific implant concept may offer predictable short- to medium-term clinical performance in carefully selected cases of severe alveolar bone atrophy.

From a clinical standpoint, the findings are particularly relevant for patients in whom conventional endosseous implant placement would require extensive bone augmentation procedures. The reviewed studies illustrate how digitally designed, custom-manufactured subperiosteal implants can be adapted to the residual bone anatomy, potentially reducing the need for complex reconstructive interventions. This reflects the growing role of digital planning, CAD-CAM manufacturing, and personalized implant design in contemporary implant dentistry.

However, the reported survival rates should be interpreted within the context of the available evidence. The included studies differed substantially in patient characteristics, anatomical indications, implant materials, prosthetic protocols, and follow-up duration. Furthermore, the review did not identify comparative clinical trials evaluating CAD-CAM subperiosteal implants against alternative treatment options such as guided bone regeneration, short implants, or conventional endosseous implant therapy. Consequently, the current evidence does not support conclusions regarding the superiority of one treatment strategy over another.

Another important consideration is the limited volume of clinical evidence. Only seven studies met the inclusion criteria, with relatively small patient cohorts and follow-up periods of up to four years. In addition, several potentially relevant prognostic factors—including opposing dentition and gingival biotype—were poorly documented across the available literature. The authors therefore emphasize the need for larger comparative studies with standardized outcome measures and greater incorporation of patient-reported outcome measures (PROMs) to better define the long-term role of CAD-CAM subperiosteal implants in implant-supported rehabilitation.

7. Clinical Applications

The findings of this review are primarily applicable to the rehabilitation of partially edentulous patients with severe alveolar bone atrophy, particularly in situations where conventional implant placement would require extensive bone grafting procedures. Within the limitations of the available evidence, CAD-CAM subperiosteal implants appear to represent a customized treatment option that combines digital planning with patient-specific implant fabrication to address challenging anatomical conditions.

The reviewed studies also describe the use of these implants in selected maxillofacial reconstructive cases following oncologic surgery, illustrating their potential role when conventional implant placement is compromised by substantial bone loss. Nevertheless, the authors stress that the current evidence remains limited and does not yet establish clear clinical indications relative to other reconstructive or implant-based treatment modalities. Future comparative investigations will be required before definitive treatment recommendations can be made.

8. Level of Evidence, Limitations and Transparency

As a scoping review, this publication is intended to map the available evidence rather than provide a quantitative synthesis or establish definitive clinical recommendations. Consequently, its level of evidence is lower than that of a systematic review with meta-analysis or a randomized controlled trial. Nevertheless, it offers a valuable overview of the current literature and highlights important gaps in knowledge regarding the use of CAD-CAM subperiosteal implants for fixed partial restorations.

The strength of the conclusions is limited by several methodological factors acknowledged by the authors. Only seven clinical studies met the inclusion criteria, representing 96 patients and 121 implants. Considerable heterogeneity existed across the included studies with respect to patient selection, surgical protocols, implant materials, prosthetic designs, and follow-up duration. Furthermore, no direct comparisons with conventional bone augmentation procedures or endosseous implant therapy were available, making it impossible to determine the relative effectiveness of these treatment approaches. Important clinical variables, including opposing dentition and gingival biotype, were also inconsistently reported.

Regarding transparency, the authors state that no conflicts of interest were identified. They also report that the study received no specific external funding. In addition, the manuscript discloses that ChatGPT was used exclusively to improve readability and language, while the authors retained full responsibility for the scientific content of the publication.

9. Key Study Highlights

• Study design: Scoping Review conducted according to the PRISMA-ScR guidelines.
• Level of evidence: Evidence mapping based on observational clinical studies; lower than a systematic review or meta-analysis.
• Studies included: 7 clinical studies.
• Patient population: 96 partially edentulous patients.
• Number of implants: 121 CAD-CAM subperiosteal implants.
• Follow-up period: Between 1 and 4 years.
• Primary outcome: Implant survival.
• Secondary outcomes: Biological and mechanical complications.
• Main finding: Weighted mean implant survival rate of 99.17%, with a single implant failure reported among 121 implants.
• Biological complications: 4.13% overall incidence.
• Mechanical complications: 7.44% overall incidence.
• Scientific conclusion: CAD-CAM subperiosteal implants may represent a reliable treatment option for selected cases of severe alveolar bone atrophy requiring fixed partial rehabilitation, although the current evidence remains limited and further comparative research is needed.
• Major limitations: Small number of available studies, limited sample size, heterogeneous clinical protocols, and lack of comparative trials.

10. Scientific Impact

This review represents one of the first publications to specifically examine CAD-CAM subperiosteal implants used for fixed partial implant-supported restorations, providing a focused assessment of an emerging indication that has received relatively little attention in the scientific literature. Whereas previous reviews have largely concentrated on full-arch rehabilitation of severely atrophic jaws, this work expands the evidence base by addressing partial edentulism as a distinct clinical scenario.

The review also reflects the ongoing evolution of digital implant dentistry. Advances in three-dimensional imaging, virtual surgical planning, and CAD-CAM manufacturing have transformed the concept of subperiosteal implants from a historical treatment modality into a modern patient-specific reconstructive solution. Although the available evidence suggests encouraging clinical outcomes, the authors appropriately refrain from presenting these findings as definitive proof of clinical superiority.

Perhaps the most significant contribution of this publication lies in identifying priorities for future research. The authors emphasize the need for prospective comparative studies evaluating CAD-CAM subperiosteal implants against conventional reconstructive approaches, including bone augmentation techniques and endosseous implant therapy. They also advocate for standardized outcome measures, longer follow-up periods, and greater incorporation of patient-reported outcome measures (PROMs) to better define the long-term clinical value of this personalized treatment approach.

11. Editorial Conclusion

This scoping review provides an important overview of the current evidence supporting the use of CAD-CAM subperiosteal implants for fixed partial rehabilitation in patients with severe alveolar bone atrophy. The available clinical studies report encouraging implant survival and relatively low complication rates over follow-up periods of up to four years. However, these findings should be interpreted with appropriate caution because they are based on a limited number of heterogeneous observational studies. As digital workflows continue to expand the possibilities of personalized implant therapy, well-designed comparative clinical trials will be essential to establish the long-term role of CAD-CAM subperiosteal implants within contemporary implant dentistry.