Five-Year Comparative Study of Zygomatic and Subperiosteal Implants: Clinical Outcomes, Complications, and Treatment Strategies for Severe Maxillary Atrophy

Five-Year Comparative Study of Zygomatic and Subperiosteal Implants: Clinical Outcomes, Complications, and Treatment Strategies for Severe Maxillary Atrophy

1. Scientific Reference

• Full Title: Five-Year Comparative Study of Zygomatic and Subperiosteal Implants: Clinical Outcomes, Complications, and Treatment Strategies for Severe Maxillary Atrophy
• Authors: Rafal Zielinski and colleagues
• Journal: Journal of Clinical Medicine
• Year: 2025
• Volume: 14
• Article: 661
• DOI: 10.3390/jcm14030661

2. Scientific Background

The management of severe maxillary atrophy remains one of the major challenges in implant rehabilitation. Conventional protocols based on bone grafting, sinus elevation procedures, or guided bone regeneration can achieve predictable outcomes, but at the cost of increased treatment duration, surgical morbidity, and therapeutic expenses.

In this context, two alternatives have experienced significant development:

• zygomatic implants, anchored in the zygomatic bone;
• next-generation customized subperiosteal implants, designed using digital technologies and metal 3D printing.

Although both approaches are currently used in cases of extreme maxillary atrophy, few studies have directly compared them over an extended follow-up period.

3. Study Objective

The objective of this study was to compare the clinical performance of zygomatic implants and customized subperiosteal implants over a five-year period in the rehabilitation of severely atrophic maxillae.

The authors analyzed:

• implant survival rates;
• biological and surgical complications;
• soft tissue stability;
• postoperative sinus lesions;
• functional and prosthetic outcomes;
• therapeutic implications of each treatment strategy.

4. Methodology

The study was a single-center retrospective cohort conducted between 2010 and 2023, with a minimum follow-up period of five years for all patients.

Study Population

The cohort included 170 patients divided into:

• 89 patients treated with customized subperiosteal implants;
• 81 patients treated with zygomatic implants.

All patients presented severe maxillary atrophy classified as Cawood Class V or VI.

Evaluated Criteria

The authors evaluated:

• implant survival;
• prosthetic success;
• postoperative complications;
• sinus lesions;
• soft tissue recession;
• peri-implant inflammation;
• implant mobility;
• surgical duration.

Statistical analysis was based on Mann–Whitney, Kruskal–Wallis, Fisher, and ANOVA tests, with the significance threshold set at p < 0.05.

5. Main Results

Implant Survival

Both solutions demonstrated very high five-year survival rates:

• zygomatic implants: 96.3%;
• subperiosteal implants: 97.1%.

No statistically significant difference was observed between the two groups (p = 0.278).

Complications

Zygomatic implants showed a greater number of anatomical complications:

• sinus complications: 12.4%;
• risk of orbital perforation;
• more frequent postoperative sinusitis;
• a higher number of tissue dehiscences.
• Subperiosteal implants presented:
• fewer sinus lesions;
• fewer soft tissue recessions;
• less peri-implant inflammation;
• better long-term soft tissue stability.

Surgical Time

Zygomatic implants required a shorter surgical duration.

Subperiosteal implants required more operative time due to:

• device customization;
• bone adaptation;
• soft tissue management;
• possible use of bone chips and the buccal fat pad.

Immediate Loading

Both techniques allowed immediate loading with delivery of screw-retained provisional prostheses within 24 hours after surgery.

6. Clinical Analysis

The main value of this study lies in the fact that it does not focus solely on implant survival rates. The authors demonstrate that two techniques may achieve similar success rates while exposing patients to very different complication profiles.

Zygomatic implants appear particularly effective when immediate fixed rehabilitation is sought in patients with extreme maxillary atrophy. Their principal advantage remains the absence of prior bone grafting and the speed of the therapeutic protocol. However, their proximity to the maxillary sinus and orbit requires a high level of surgical expertise.

Conversely, modern subperiosteal implants benefit from advances in digital planning, CBCT imaging, and additive manufacturing. Their customized design appears to promote better soft tissue integration and reduce sinus-related complications.

A particularly interesting aspect concerns failure management. According to the authors, removal of a zygomatic implant may complicate future reimplantation due to resorption of the zygomatic site. In contrast, a subperiosteal implant can be redesigned and reinserted after healing, providing greater therapeutic flexibility.

7. Clinical Applications

The results of this study directly concern:

• severely atrophic completely edentulous maxillae;
• patients refusing major bone grafting procedures;
• situations requiring immediate loading;
• complex cases with limited residual bone volume;
• indications for digitally planned implant surgery.

The study suggests that the choice between zygomatic implants and subperiosteal implants should be guided primarily by the patient’s anatomy and the expertise level of the surgical team.

8. Level of Evidence and Limitations

This publication corresponds to a retrospective comparative study.

Although the five-year follow-up represents a major strength, several limitations should be highlighted:

• absence of randomization;
• single-center study;
• non-random allocation of patients;
• risk of selection bias;
• inability to establish a formal causal relationship.

The authors themselves recommend randomized controlled trials to confirm these findings.

9. Key Points

• 170 patients followed for 5 years.
• High implant survival in both groups (>96%).
• No significant difference in survival between the techniques.
• More sinus-related complications with zygomatic implants.
• Better soft tissue stability with subperiosteal implants.
• Immediate rehabilitation possible with both approaches.
• Shorter surgical time for zygomatic implants.
• More favorable reintervention possibilities with subperiosteal implants.
• Major importance of digital planning and CBCT.

10. Scientific Impact

This study illustrates the recent evolution of customized subperiosteal implants, long considered historical devices that had become obsolete. Thanks to 3D printing and CAD/CAM technologies, these implants are now re-emerging as a credible option for patients with severe maxillary atrophy.

The results suggest that improved peri-implant soft tissue conditions may represent a major clinical advantage of modern subperiosteal implants. Conversely, zygomatic implants retain their value in rapid immediate-loading protocols, although at the cost of greater anatomical complexity.

This publication therefore contributes to the ongoing debate regarding rehabilitation strategies for extreme maxillary atrophy and highlights the growing importance of digital customization in implant treatment planning.

11. Editorial Conclusion

This five-year comparative study demonstrates that both zygomatic implants and customized subperiosteal implants can achieve very high survival rates in patients with severe maxillary atrophy. However, behind this apparent clinical equivalence lie distinct biological profiles. Zygomatic implants stand out for their rapid implementation and their ability to support immediate loading, whereas subperiosteal implants appear to offer better soft tissue stability and a reduction in sinus-related complications. These findings reinforce the concept that therapeutic success depends less on the selection of a universal technique than on individualized treatment planning based on patient anatomy, prosthetic objectives, and the available surgical expertise.