Long-Term Outcomes of Fitted Subperiosteal Implants: A Report of Twelve Patient Cases

Stefan Zwerger, Mario Hakim Abu-Id, Thomas Kreusch

Full text link: https://pubmed.ncbi.nlm.nih.gov/17972118/

Long-Term Outcomes of Fitted Subperiosteal Implants: A Report of Twelve Patient Cases

1. Scientific Reference

• Study Title: Long-Term Results of Fitting Subperiosteal Implants: Report of Twelve Patient Cases
• Authors: Stefan Zwerger, Mario Hakim Abu-Id, Thomas Kreusch
• Journal: Mund-, Kiefer- und Gesichtschirurgie (not specified in the information provided, but identifiable through the DOI)
• Publication Year: 2007
• DOI: 10.1007/s10006-007-0081-5

2. Scientific Background

Subperiosteal implants represented one of the earliest treatment options developed for patients with severe jawbone atrophy before the widespread adoption of modern endosseous dental implants. Rather than being inserted into the bone, these custom-made frameworks rested directly on the bone surface beneath the periosteum. As implant dentistry evolved and osseointegration became the standard of care, subperiosteal implants gradually fell out of routine clinical use because of concerns regarding their long-term biological performance.

This publication examines patients who experienced complications after receiving subperiosteal implants, offering valuable insight into the long-term management of these historical devices. From an oral surgery and implant rehabilitation perspective, the study highlights the clinical challenges associated with treating late implant failures and planning subsequent reconstructive procedures when significant bone loss has occurred.

3. Study Objective

The purpose of this study was to document the clinical complications observed in patients treated with subperiosteal implants and to describe the consequences following implant removal. The authors also sought to evaluate the impact of these complications on future implant rehabilitation, particularly in cases where bone atrophy limited the placement of conventional osseointegrated dental implants.

4. Methodology

This publication is a case series involving twelve patients who developed complications related to previously placed subperiosteal implants.

The authors describe the clinical findings, the conditions observed after implant removal, and the subsequent possibilities for oral rehabilitation using osseointegrated implants.

The duration of follow-up, patient demographics, evaluation criteria, and detailed surgical protocols are not specified in the information provided.

5. Main Findings

The reported cases demonstrated that subperiosteal implants were associated with several clinically significant complications. The most frequently described conditions included implant exposure, inflammatory reactions, infection, fistula formation, and implant mobility.

Following removal of the implants, the clinicians consistently observed advanced alveolar bone atrophy. In many patients, the remaining bone volume was insufficient to support conventional osseointegrated implant placement without prior autogenous bone grafting.

Based on these observations, the authors emphasize the importance of regular clinical monitoring for patients carrying subperiosteal implants. They also indicate that implant removal should be considered when complications become persistent and note that complete oral rehabilitation often requires additional preprosthetic surgical procedures.

6. Clinical Analysis

Rather than evaluating the effectiveness of subperiosteal implants themselves, this study illustrates the long-term clinical consequences that may arise when complications develop around these historical implant systems. One of its most relevant observations is that implant failure may extend beyond local infection or mechanical instability, ultimately compromising the remaining bone available for future rehabilitation.

From a clinical perspective, these findings reinforce the importance of carefully assessing residual bone volume after explantation and anticipating the potential need for bone augmentation before implant-supported rehabilitation can be considered. The report is particularly relevant for clinicians who occasionally encounter patients treated decades ago with implant systems that are no longer routinely used.

Nevertheless, the conclusions should be interpreted cautiously. As a case series, the study provides descriptive clinical observations rather than comparative evidence. It cannot establish complication rates, identify predictive factors, or determine whether alternative treatment strategies would have produced different outcomes. Consequently, its findings should be viewed as valuable clinical experience rather than definitive evidence guiding contemporary implant therapy.

7. Clinical Applications

The observations reported in this study may be particularly relevant for:

• long-term follow-up of patients with historical subperiosteal implants;
• management of biological complications in implant dentistry;
• assessment of severe alveolar bone atrophy after implant removal;
• planning secondary implant rehabilitation in patients with limited residual bone;
• preprosthetic surgical procedures and autogenous bone grafting when reconstruction is required before placement of osseointegrated implants.

The information provided does not support extrapolating these findings to contemporary endosseous implant systems.

8. Level of Evidence, Limitations and Transparency

This publication represents a case series, corresponding to a low level of clinical evidence compared with controlled clinical trials or systematic reviews.

Although the study provides useful documentation of real-world complications, its design does not allow conclusions regarding incidence, causality, or comparative treatment outcomes.

The methodological limitations are not explicitly detailed in the information provided. No control group or comparative analysis is described.

No conflicts of interest or financial relationships involving the authors are reported in the available information.

9. Key Study Highlights

• Study design: Case series.
• Level of evidence: Low.
• Study population: Twelve patients.
• Number of patients: 12.
• Follow-up duration: Not specified in the information provided.
• Primary outcome assessed: Clinical complications associated with subperiosteal implants and findings after implant removal.
• Main result: Implant-related complications were frequently associated with severe residual bone atrophy, complicating subsequent implant rehabilitation.
• Scientific conclusion: Regular clinical surveillance is recommended for patients with subperiosteal implants, and implant removal should be considered when complications become persistent.
• Main limitations: Case series design; methodological limitations are not detailed in the available information.

10. Scientific Impact

This study contributes to the historical understanding of implant dentistry by documenting the long-term clinical challenges associated with subperiosteal implant therapy. Rather than evaluating an emerging technique, it provides practical evidence regarding the management of patients who received implant systems that predate contemporary osseointegrated protocols.

Its principal contribution lies in highlighting how chronic complications may compromise future reconstructive options through progressive bone loss. These observations remain relevant for oral surgeons and implant specialists involved in the management of legacy implant cases, where treatment planning frequently extends beyond implant removal to include bone reconstruction and staged rehabilitation. Although the study provides only descriptive evidence, it enriches the clinical literature concerning long-term implant complications and emphasizes the importance of continued surveillance in affected patients.

11. Editorial Conclusion

This twelve-patient case series offers valuable clinical insight into the long-term complications associated with subperiosteal implants. The reported observations suggest that persistent biological complications may result in substantial alveolar bone loss, making future implant rehabilitation considerably more complex. While the study’s low level of evidence limits the generalizability of its conclusions, it remains an important contribution to the understanding of historical implant systems and the surgical challenges encountered during their long-term management.