Polyetheretherketone subperiosteal implant retaining a maxillary fixed prosthesis: A case series

Polyetheretherketone Subperiosteal Implant Retaining a Maxillary Fixed Prosthesis: A Case Series

1. Scientific Reference

• Study Title: Polyetheretherketone Subperiosteal Implant Retaining a Maxillary Fixed Prosthesis: A Case Series
• Authors: Mohammed A. El-Sawy, Mohamed E. ELgamal, Wael M. Ahmed, Medhat A. EL-daker, Salah A. Hegazy
• Journal: The Journal of Prosthetic Dentistry
• Year of Publication: 2024
• DOI: 10.1016/j.prosdent.2022.08.027

2. Scientific Background

The rehabilitation of completely edentulous patients with advanced maxillary bone resorption remains one of the most challenging situations in implant dentistry. Conventional treatment approaches for severe maxillary atrophy often involve bone augmentation procedures, sinus floor elevation, or zygomatic implants. While these techniques can provide predictable outcomes, they frequently require extensive surgery, multiple treatment stages, and prolonged rehabilitation periods.

Recent advances in digital dentistry, computer-aided design and manufacturing (CAD/CAM), and biomaterials have created opportunities for alternative treatment strategies. Patient-specific subperiosteal implants have re-emerged as a potential solution for individuals who are unwilling or unsuitable to undergo complex reconstructive procedures. Polyetheretherketone (PEEK), a high-performance polymer with favorable mechanical and biological properties, has attracted increasing attention for implant-supported prosthetic applications. This study explores the clinical feasibility of combining digital workflows with customized PEEK subperiosteal implants for the management of severely resorbed edentulous maxillae.

3. Study Objective

The primary objective of this investigation was to evaluate the preliminary clinical performance of CAD/CAM-manufactured PEEK subperiosteal implants used to support fixed maxillary prostheses in patients with severe maxillary ridge resorption.

The authors specifically aimed to assess whether this single-stage surgical approach could provide a viable treatment option for completely edentulous individuals who declined bone grafting procedures, sinus augmentation, or other multi-stage surgical protocols.

4. Methodology

This publication is an observational case series conducted at the Faculty of Dentistry, Mansoura University, Egypt.

Four completely edentulous patients presenting with severe maxillary ridge atrophy classified as Cawood and Howell Class IV or V were included. All participants sought fixed prosthetic rehabilitation and declined conventional augmentation procedures.

A fully digital workflow was employed. Computed tomography imaging, digital prosthetic planning, virtual implant design, and CAD/CAM manufacturing were used to create individualized PEEK subperiosteal frameworks. The implants were surgically placed during a single procedure and secured with fixation screws.

Following soft-tissue healing, definitive maxillary prostheses were fabricated and delivered. Patients were monitored for implant stability, soft-tissue health, infection, prosthetic complications, implant exposure, and overall clinical performance. The primary follow-up period was 12 months, while two patients were observed for up to 24 months.

5. Main Findings

All four patients completed treatment and follow-up evaluations.

During the early postoperative period, healing was uneventful in most cases. One patient experienced partial framework exposure near a maxillary canine abutment. This complication was managed surgically through flap release and resuturing.

At the 12-month assessment, all implants remained clinically stable and functional. No prosthetic fractures, infections, purulent discharge, or implant mobility were reported. The peri-implant soft tissues appeared healthy throughout the observation period.

Two participants reached a 24-month follow-up stage. Radiographic evaluation revealed no radiolucent areas surrounding the fixation screws, suggesting continued stability of the implant-supported reconstruction.

Overall, the clinical outcomes reported in this series indicate favorable short-term performance of the customized PEEK subperiosteal implant system within the limitations of the study design.

6. Clinical Analysis

This study provides preliminary evidence regarding a relatively novel approach to the rehabilitation of severely atrophic maxillae. Rather than relying on conventional endosseous implants combined with bone reconstruction procedures, the authors explored the use of patient-specific subperiosteal implants manufactured from PEEK.

The clinical relevance of this concept lies in its potential to reduce treatment complexity for selected patients. By adapting the implant framework directly to the residual bone anatomy, extensive grafting procedures may potentially be avoided. For individuals who reject multi-stage surgeries or present anatomical limitations, such an approach could represent an alternative pathway toward fixed prosthetic rehabilitation.

Another notable aspect is the apparent short-term soft-tissue compatibility observed in this series. The authors discuss previous evidence suggesting favorable epithelial responses to PEEK, which may contribute to peri-implant tissue stability. However, the present study was not designed to directly compare biological performance with titanium or other implant materials.

Interpretation of the findings must remain cautious. The study includes only four patients, lacks a control group, and provides limited long-term follow-up data. Consequently, the results should be viewed as proof of clinical feasibility rather than definitive evidence supporting widespread adoption. Larger prospective investigations are necessary before drawing conclusions regarding long-term survival, complication rates, or comparative effectiveness.

7. Clinical Applications

The findings may be relevant in selected clinical scenarios involving:

• Severe maxillary ridge atrophy.
• Complete maxillary edentulism.
• Patients refusing bone grafting procedures.
• Patients seeking fixed implant-supported rehabilitation through a single-stage surgical approach.
• Digitally planned implant rehabilitation using CAD/CAM workflows.
• Customized implant-supported prosthetic treatment in anatomically challenging cases.

The study also illustrates the integration of advanced digital planning, patient-specific implant design, and modern biomaterials within contemporary oral and implant surgery protocols. However, these applications should currently be considered exploratory due to the limited evidence available.

8. Level of Evidence, Limitations, and Transparency

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

Several methodological limitations are acknowledged by the authors. The study involved only four patients, lacked a comparison group, and provided a relatively short observation period. These factors limit the generalizability of the findings and prevent robust conclusions regarding long-term outcomes.

The authors explicitly recommend future prospective studies involving larger patient populations and longer follow-up periods to better evaluate the clinical performance of PEEK subperiosteal implants.

No specific conflicts of interest were reported within the provided material. The acknowledgments section notes contributions from collaborators involved in CAD/CAM implant design and prosthetic laboratory procedures.

9. Key Study Points

• Study type: Observational case series
• Level of evidence: Low
• Population: Completely edentulous patients with severe maxillary atrophy
• Number of patients: 4
• Number of implants: 4 customized PEEK subperiosteal implants
• Primary follow-up duration: 12 months
• Maximum reported follow-up: 24 months in 2 patients
• Primary outcome assessed: Clinical stability and complication profile
• Main finding: Stable implant-supported rehabilitation without infection, prosthetic fracture, or implant failure during the reported follow-up period
• Scientific conclusion: Customized PEEK subperiosteal implants may represent a promising treatment option for severely atrophic maxillary ridges
• Main limitations: Small sample size, absence of a control group, and limited follow-up duration

10. Scientific Impact

This study contributes to the growing body of literature investigating digitally manufactured patient-specific subperiosteal implants. Its significance lies not in providing definitive clinical evidence, but in demonstrating the practical feasibility of combining CAD/CAM technology with PEEK-based implant frameworks for complex maxillary rehabilitation.

The work expands current knowledge regarding alternative treatment options for severe maxillary atrophy, particularly in patients who decline extensive reconstructive surgery. It also highlights the potential role of advanced polymers in implant-supported prosthodontics and oral rehabilitation.

From a research perspective, the study serves as an early clinical report that may support the development of future prospective trials. The findings help identify areas requiring further investigation, including long-term implant survival, biological complications, prosthetic maintenance requirements, and comparisons with titanium-based subperiosteal implant systems and other advanced rehabilitation techniques.

11. Editorial Conclusion

This case series presents an innovative digital workflow for the rehabilitation of severely atrophic edentulous maxillae using customized PEEK subperiosteal implants. The short-term outcomes reported by the authors suggest satisfactory implant stability and favorable soft-tissue health, with limited complications during follow-up. Nevertheless, the evidence remains preliminary due to the small number of patients and restricted observation period. Larger, well-designed clinical studies are required to determine the long-term role of this approach within contemporary implant dentistry and oral rehabilitation.