Survival and complications of zygomatic implants: a systematic review

Survival and Complications of Zygomatic Implants: A Systematic Review

1. Scientific Reference

• Study Title: Survival and Complications of Zygomatic Implants: A Systematic Review
• Authors: Bruno Ramos Chrcanovic, Mauro Henrique Nogueira Guimarães Abreu
• Scientific Journal: Oral and Maxillofacial Surgery
• Year of Publication: 2013
• DOI: 10.1007/s10006-012-0331-z

2. Scientific Background

The management of severely atrophic maxillae represents a major challenge in dental implantology and oral surgery. When the residual bone volume is insufficient to allow the placement of conventional implants, several therapeutic strategies may be considered, including bone grafting procedures, sinus augmentation techniques, or the use of implants anchored in more distant osseous structures.

Zygomatic implants were developed to provide an alternative to complex bone reconstruction procedures in patients presenting with advanced maxillary resorption. This approach is also used in certain maxillofacial reconstruction contexts following tumor resection.

Despite growing clinical interest in this technique, the literature available at the time of this review consisted primarily of case series and observational studies. The authors therefore undertook a critical synthesis of the available evidence in order to evaluate the survival of zygomatic implants as well as the complications associated with their use.

3. Study Objective

The primary objective of this systematic review was to answer two essential clinical questions:

• What is the survival rate of zygomatic implants?
• What are the most frequently reported complications following their placement?

The authors also sought to better understand the timing of implant failures and the evolution of implant survival over a long follow-up period.

4. Methodology

This research was conducted according to the principles of the PRISMA protocol. An electronic search was performed in PubMed without restrictions regarding language or publication date.

The inclusion criteria concerned clinical studies reporting the use of zygomatic implants in patients presenting with severe maxillary atrophy or certain complex maxillary reconstruction situations.

A total of 42 studies were retained for analysis following publication screening and additional manual searches of reference lists. Extracted data included:

• number of patients;
• number of zygomatic implants placed;
• implant failures;
• postoperative complications;
• follow-up periods.

The authors also performed a survival analysis to estimate cumulative survival rates up to twelve years after implant placement.

5. Main Results

The 42 included studies comprised 1,145 patients and 2,402 zygomatic implants. Among these implants, 56 were reported as failures during follow-up.

Analysis of the data demonstrated that the majority of failures occurred early, primarily before prosthetic loading or at the time of abutment connection, within the first six months following surgery.

The cumulative survival rate calculated over twelve years reached 96.7%, indicating high implant survival within the analyzed studies.

Regarding the reported biological complications, the authors identified:

• 70 cases of sinusitis;
• 48 cases of soft tissue infection;
• 15 cases of paresthesia;
• 17 oroantral fistulas.

The authors emphasize, however, that these figures may be underestimated because many studies did not systematically report either the presence or absence of complications.

Immediate loading protocols demonstrated favorable outcomes with high survival rates in the analyzed series. Conversely, studies involving patients who underwent maxillary resection for tumor treatment presented lower success rates.

6. Clinical Analysis

This review provides an overall perspective on the clinical performance of zygomatic implants in situations where conventional therapeutic options are often limited.

The main finding lies in the high level of implant survival observed despite the anatomical complexity of the treated cases. These results suggest that zygomatic implants represent a credible implant rehabilitation option for certain patients affected by severe maxillary atrophy.

Nevertheless, the data must be interpreted with caution. The methodological quality of the available studies appears heterogeneous and is based mainly on case series. The absence of control groups limits the ability to compare this approach with other solutions such as bone reconstruction procedures or conventional implant protocols.

The review also highlights an important point for clinical practice: the majority of failures occur early. This observation underlines the importance of implant planning, primary stability, and postoperative follow-up during the first months.

From a surgical standpoint, the authors remind readers that this technique involves proximity to sensitive anatomical structures such as the maxillary sinus, the orbit, and certain neurological structures. Complications remain relatively infrequent in the reported data, but their potential impact justifies careful patient selection and advanced surgical expertise.

7. Clinical Applications

The results of this review may be particularly relevant in the following situations:

• severe maxillary atrophy limiting the placement of conventional implants;
• implant rehabilitation of completely edentulous patients;
• situations where bone grafting procedures are difficult or undesirable;
• maxillofacial reconstruction following certain maxillary resections;
• implant rehabilitation protocols requiring a reduction in treatment time.

The presented data suggest that zygomatic implants may constitute a useful therapeutic solution in these contexts, while still requiring individualized assessment of surgical and prosthetic risk.

8. Level of Evidence, Limitations and Transparency

This publication is a systematic review, which represents a higher level of evidence than that provided by an isolated clinical study. However, the robustness of the conclusions depends directly on the quality of the included studies.

The authors indicate that no randomized clinical trial or controlled clinical study was identified in the analyzed literature. The majority of the available data originate from case series or observational studies.

Among the limitations highlighted:

• absence of randomized controlled trials;
• heterogeneity of the included studies;
• limited number of studies with long-term follow-up;
• possible underreporting of complications;
• difficulty in accurately assessing very long-term survival.

No specific conflicts of interest are mentioned in the provided information.

9. Key Points of the Study

• Study Type: Systematic review
• Level of Evidence: Systematic review based primarily on observational studies
• Population or Number of Studies Analyzed: 42 studies
• Number of Patients: 1,145 patients
• Number of Implants: 2,402 zygomatic implants
• Follow-up Duration: Up to 12 years for cumulative survival analysis
• Primary Outcome Evaluated: Implant survival and postoperative complications
• Main Result: Cumulative survival rate of 96.7%
• Main Complications: Sinusitis, soft tissue infections, paresthesia, and oroantral fistulas
• Scientific Conclusion: Zygomatic implants demonstrate high survival rates but require additional high-quality controlled studies.
• Potential Limitations: Absence of randomized trials and limited long-term data.

10. Scientific Impact

This review helped structure the available knowledge regarding zygomatic implants at a time when clinical data remained fragmented.

Its principal value lies in placing into perspective the results derived from a large number of publications and treated patients. The authors demonstrate that implant survival is generally favorable despite the complexity of the clinical indications involved.

The study also draws attention to an aspect that is often less emphasized: the need for monitoring sinus-related complications and peri-implant soft tissue complications.

From a scientific perspective, this publication does not definitively validate the superiority of a specific technique but highlights the potential of zygomatic implants in the rehabilitation of severely atrophic maxillae. Above all, it underscores the need for comparative prospective studies and randomized trials to better define the role of this approach within the therapeutic armamentarium of modern implantology.

11. Editorial Conclusion

This systematic review represents an important synthesis of the literature dedicated to zygomatic implants. The analyzed data suggest high implant survival in patients treated for severe maxillary atrophy or complex reconstructive situations. However, the methodological quality of the available studies remains limited and requires cautious interpretation of the results. For practitioners involved in oral surgery, maxillofacial reconstruction, and implant rehabilitation, this publication confirms the interest of zygomatic implants while emphasizing the need for advanced surgical expertise and rigorous clinical follow-up.