subperiosteal implants
Full-arch rehabilitation of severely atrophic maxilla with additively manufactured custom-made subperiosteal implants: A multicenter retrospective study
Full text links: https://pubmed.ncbi.nlm.nih.gov/38871617/
Full-Arch Rehabilitation of Severely Atrophic Maxilla with Additively Manufactured Custom-Made Subperiosteal Implants: A Multicenter Retrospective Study
1. Scientific Reference
- Study Title: Full-arch rehabilitation of severely atrophic maxilla with additively manufactured custom-made subperiosteal implants: A multicenter retrospective study
- Authors: Luigi Angelo Vaira, Andrea Biglio, Marco Roy, Giovanni Salzano, Stefania Troise, Vincenzo Abbate, Miguel Mayo-Yanez, Jerome R. Lechien, Pasquale Piombino, Giacomo De Riu
- Journal: Journal of Cranio-Maxillo-Facial Surgery
- Year of Publication: 2024
- DOI: 10.1016/j.jcms.2024.06.016
2. Scientific Background
The rehabilitation of patients with severe maxillary atrophy remains one of the most demanding challenges in implant dentistry and oral and maxillofacial surgery. Advanced bone resorption frequently limits the use of conventional endosseous implants and often requires extensive bone augmentation procedures, prolonged treatment times, and multiple surgical interventions.
Over the past decade, increasing attention has been directed toward graftless rehabilitation protocols designed to reduce treatment complexity while restoring oral function more rapidly. Although zygomatic implants have become a well-established option for severely resorbed maxillae, their placement requires advanced surgical expertise and may be associated with significant anatomical and biological complications.
Recent advances in digital workflow technologies, CAD/CAM design, and additive manufacturing have enabled the development of patient-specific subperiosteal implants. These custom-made devices are designed to adapt precisely to the patient’s anatomy and may offer an alternative treatment pathway for individuals with extreme maxillary bone deficiency who would otherwise require complex reconstructive procedures.
3. Study Objective
The primary objective of this study was to evaluate the clinical outcomes of full-arch rehabilitation performed with additively manufactured custom-made subperiosteal implants in patients presenting with severe maxillary atrophy.
The investigators specifically assessed implant survival, implant success, biological and surgical complications, peri-implant soft tissue health, and radiographic changes occurring beneath the prosthetic abutments during follow-up.
4. Methodology
This investigation was designed as a multicenter retrospective observational study conducted between August 2018 and January 2023.
A total of 36 consecutive patients diagnosed with Cawood and Howell Class V or VI maxillary atrophy were included. The study analyzed 72 custom-made subperiosteal implants used for full-arch rehabilitation.
Treatment planning was based on a fully digital workflow integrating cone-beam computed tomography (CBCT), digital impressions, prosthetic planning, and CAD/CAM design. The implants were manufactured from Grade V titanium using additive laser melting technology.
All patients underwent immediate loading with a fixed provisional prosthesis. The mean follow-up period was 30.1 months, ranging from 12 to 64 months.
Clinical and radiographic assessments focused on implant survival, implant success, peri-implant bleeding on probing, implant exposure, screw-related complications, and bone remodeling beneath the abutments.
5. Main Findings
No implant failures occurred during the observation period, resulting in an implant survival rate of 100%.
Using the modified success criteria adopted by the authors, the overall implant success rate was 90.3%.
Limited Class 1 implant exposure, corresponding to exposure of the vertical abutment arm only, was identified in seven implants (9.7%). These exposures occurred within the first postoperative year and were not associated with inflammatory symptoms.
Bleeding on probing remained relatively low throughout follow-up. It was observed in 10.4% of abutments at six months, 7.9% at one year, 10% at two years, 7% at three years, and 11.4% at four years.
Radiographic analysis demonstrated no statistically significant bone resorption beneath the abutments throughout the observation period.
Complications were generally limited. One patient developed an infection associated with loosening of a fixation screw at the zygomatic buttress. The condition resolved following screw removal and antibiotic treatment. No implant losses were reported as a consequence of this complication.
6. Clinical Analysis
This study provides valuable clinical data regarding a treatment modality that remains relatively new within modern implant rehabilitation protocols.
One of the most noteworthy findings is the complete implant survival observed throughout the follow-up period. Considering the severity of the maxillary atrophy treated, these outcomes suggest that custom-made subperiosteal implants may represent a viable option for patients who present with limited bone availability and who may otherwise require extensive reconstructive surgery.
Another clinically relevant observation concerns the stability of the supporting bone beneath the prosthetic abutments. Historically, bone resorption was one of the major limitations associated with earlier generations of subperiosteal implants. The absence of significant bone loss reported in this study suggests that contemporary implant design, digital planning, and optimized load distribution may have addressed some of the shortcomings previously associated with this treatment concept.
Soft tissue management also appears to play a critical role in treatment success. Although implant exposure occurred in a minority of cases, these events remained limited and asymptomatic. This highlights the importance of careful surgical planning and long-term maintenance of peri-implant soft tissues.
Despite these encouraging findings, caution remains necessary. The study design does not allow direct comparison with alternative approaches such as zygomatic implants or graft-based rehabilitation protocols. Therefore, the reported outcomes should be interpreted as observational evidence rather than definitive proof of superiority.
7. Clinical Applications
The findings of this study may be relevant in several clinical scenarios, including:
- Full-arch rehabilitation of severely atrophic maxillae.
- Treatment of edentulous patients with insufficient bone volume for conventional implant placement.
- Cases where extensive bone grafting procedures may not be desirable or feasible.
- Digitally planned implant rehabilitation using CAD/CAM workflows.
- Immediate-loading protocols supported by custom-made implant frameworks.
- Complex oral and maxillofacial rehabilitation requiring patient-specific implant solutions.
The study exclusively evaluated severely atrophic maxillae and does not provide evidence for other anatomical indications.
8. Level of Evidence, Limitations, and Transparency
This publication is a retrospective multicenter observational study. Consequently, its level of evidence is lower than that of prospective randomized controlled trials or comparative clinical studies.
Several limitations were acknowledged by the authors, including the retrospective design, the relatively small sample size, the absence of a control group, and the limited duration of follow-up for assessing long-term outcomes.
The authors also noted that universally accepted success criteria for modern subperiosteal implants are currently lacking, which may complicate comparisons across studies.
Regarding transparency, the investigators reported no conflicts of interest. The research was funded by the University of Sassari through its institutional research program.
9. Key Study Highlights
- Study Type: Multicenter retrospective observational study
- Level of Evidence: Retrospective clinical study
- Patient Population: Patients with severe maxillary atrophy (Cawood and Howell Class V–VI)
- Number of Patients: 36
- Number of Implants: 72
- Mean Follow-Up: 30.1 months
- Primary Outcome: Survival and success of custom-made subperiosteal implants
- Implant Survival Rate: 100%
- Implant Success Rate: 90.3%
- Bone Remodeling Outcome: No significant bone resorption detected beneath the abutments
- Main Conclusion: Custom-made additively manufactured subperiosteal implants demonstrated favorable short- to medium-term outcomes for full-arch rehabilitation of severely atrophic maxillae
- Key Limitations: Retrospective design, absence of control group, limited sample size, and lack of long-term follow-up data
10. Scientific Impact
This study contributes meaningful clinical evidence to a field where available data remain relatively limited. Modern subperiosteal implants manufactured through additive technologies represent a significant evolution from historical designs, benefiting from advances in digital planning, biomechanical optimization, and personalized implant fabrication.
The investigation provides one of the larger clinical series focused exclusively on full-arch rehabilitation of severely atrophic maxillae using patient-specific subperiosteal implants. Its findings support the growing body of evidence suggesting that contemporary subperiosteal implant systems may offer predictable outcomes when carefully planned and executed.
Beyond reporting survival and complication rates, the study contributes important information regarding soft tissue behavior and peri-abutment bone stability. These observations may help refine future implant designs and surgical protocols.
At the same time, the study highlights the need for prospective investigations with longer follow-up periods and comparative study designs to better define the role of custom-made subperiosteal implants within the broader spectrum of advanced implant rehabilitation strategies.
11. Editorial Conclusion
This multicenter retrospective study provides encouraging evidence supporting the use of additively manufactured custom-made subperiosteal implants for the rehabilitation of severely atrophic maxillae. High survival rates, stable peri-abutment bone conditions, and manageable complication rates suggest that this technology may represent a valuable treatment option in carefully selected patients. Nevertheless, the observational nature of the study and the current lack of long-term evidence warrant cautious interpretation, emphasizing the need for further prospective research before definitive clinical recommendations can be established.
