Clinical context and challenges of severe alveolar atrophy

Alveolar bone atrophy, whether resulting from long-standing dental loss or advanced periodontal diseases, severely compromises prosthetic stability and implantation possibilities. In the presence of marked resorption (Classes V-VI), the use of conventional endosseous implants is often precluded by the lack of volume required to accommodate standard dimensions (diameter ≥ 3.3 mm and length ≥ 8 mm) and anatomical safety distances. While solutions such as sinus lift exist in the maxilla, mandibular atrophy offers fewer regional anchorage options, making vertical bone augmentations technically complex and unpredictable.

The objective of this cohort study is to evaluate the changes in oral health-related quality of life and patient satisfaction following rehabilitation with customised subperiosteal implants. These titanium devices, designed via a CAD/CAM digital workflow based on CBCT models, are directly adapted to the patient's external cortical anatomy to bypass the limitations of endosseous anchorage.

The authors test the hypothesis that reconstruction with custom-made subperiosteal implants results in a clinically significant improvement in quality of life twelve months after surgery, accompanied by a high level of postoperative satisfaction in these patients facing a conventional therapeutic impasse.

A methodology rooted in the digital workflow

This prospective cohort study, conducted at the "Evangelismos" General Hospital of Athens in 2025, included 9 adult patients (5 men) presenting with severe localised alveolar atrophy in the maxilla. The objective was to evaluate the efficacy of custom-made subperiosteal implants for clinical cases where conventional endosseous implants were technically unfeasible.

The protocol is based on rigorous digital engineering:

• CAD/CAM design: Based on CBCT scans, custom titanium frameworks were modelled to precisely fit the external cortical bone of each patient.
• Surgical procedure: The standardised protocol included flap elevation, subperiosteal dissection to expose the recipient bone, and stabilisation of the titanium frame with fixation screws prior to tension-free mucosal closure.
• Follow-up and evaluation: Data were collected preoperatively and during a final evaluation at 12 months of follow-up after the placement of the fixed prosthesis.

The primary outcome was the change in quality of life, measured by the OHIP-14 questionnaire. Overall satisfaction was quantified using a numeric rating scale (NRS). Secondary outcomes included implant stability, complications (infections, dehiscences, exposures) and the need for reintervention. Statistical analysis used the Wilcoxon signed-rank test to compare baseline scores with the results obtained at one year.

Drastic improvement in quality of life and implant stability at 12 months

The study involved a cohort of 9 patients (5 males and 4 females) presenting with severe alveolar atrophy (Cawood and Howell classes V–VI). In all cases, the custom-made implants were positioned in the maxilla. The 12-month results show a major improvement in oral health indicators and overall satisfaction.

Impact on quality of life (OHIP-14) and satisfaction (NRS)

The improvement in oral health-related quality of life is statistically significant according to the Wilcoxon test. The median OHIP-14 score dropped sharply, shifting from a state of severe disability to a near absence of functional or psychosocial complaints.

Indicator (Median values)	Preoperative	12 months postoperative	Significance
Total OHIP-14 score	41	1	p < 0.05 (significant)
Total satisfaction (NRS)	17	58	p < 0.05 (significant)

This positive trend is consistent across all domains of the OHIP-14 and all items of the NRS scale, confirming that the prosthetic stability achieved by the subperiosteal implant effectively compensates for the initial anatomical limitations.

Clinical follow-up and complications

In terms of surgical safety, no major adverse events were reported. Clinical and radiographic observations at 12 months confirm the viability of the technique:

• Implant stability: 100% of the implants remained clinically and radiographically stable at the end of the follow-up.
• Minor complications: One case of early wound dehiscence was observed, as well as a localised implant exposure in the anterior palate in another patient.
• Reintervention: No major reoperation was required for the study cohort.

The authors emphasise that despite these promising results, the small sample size (n=9) requires cautious interpretation of these short-term preliminary data.

Clinical analysis and limitations of the approach

The results of this study demonstrate a radical transformation in the patients' experience. The sharp drop in the OHIP-14 score (from 41 to 1) indicates that the customised subperiosteal implant does not merely restore function; it almost completely eliminates the social and functional disability associated with total edentulism in situations of extreme atrophy. For the practitioner, the 100% stability at 12 months validates the precision of the passive fit enabled by the CAD/CAM digital workflow.

However, caution is still advised. With a small sample size of 9 patients and a limited follow-up of 12 months, these data remain preliminary. The study focuses exclusively on the maxilla, where bone density and sinus pneumatisation make the alternative of zygomatic implants possible but invasive. Although two minor complications (dehiscence and exposure) were managed, they serve as a reminder that soft tissue management remains the critical point of this technique.

Compared to massive bone grafts, this approach reduces invasiveness and treatment time, while providing immediate prosthetic stability. These results suggest that the modern subperiosteal implant is a solid fallback option for cases where conventional implantology fails due to a lack of sufficient bone support.

Summary of results

This cohort study of 9 patients reports a dramatic improvement in quality of life (OHIP-14 score dropping from 41 to 1 in 12 months) and satisfaction (NRS rising from 17 to 58 out of 60). At one year, implant stability reaches 100%, despite two minor complications (dehiscence and local exposure) managed without implant failure.

In practical terms, for the practitioner:

• Alternative to grafts: For severe atrophy (Cawood V-VI), the CAD/CAM titanium framework enables fixed rehabilitation without resorting to extensive bone augmentation or zygomatic implants.
• Digital reliability: The individualised design on CBCT ensures precise adaptation to the patient's cortical anatomy, secured by osteosynthesis screws for immediate primary stability.
• Mucosal monitoring: The long-term success of the treatment relies on tension-free flap closure; closely monitor healing to prevent any exposure of the metal framework.

Faced with insufficient bone volumes to meet minimum safety dimensions (notably 3.3 mm in diameter and 8 mm in length), the practitioner must often turn to extensive augmentation procedures or complex regional anchorages. Customised subperiosteal implants offer an alternative by resting directly on the outer cortex, beneath the periosteum. This prospective study followed 9 patients (including 5 men) who benefited from this technology in the maxilla. The surgical protocol was based on a crestal approach, exposure of the recipient bone and the fixation of a titanium framework stabilised by osteosynthesis screws, all designed via a digital workflow (CBCT and CAD/CAM). The results after 12 months of follow-up show a dramatic improvement in oral health-related quality of life. The median OHIP-14 score decreased from 41 preoperatively to just 1 at the final follow-up. Patient satisfaction, assessed via a numeric rating scale (NRS), followed a similar progression, increasing from a median score of 17 to 58. Clinically, radiographic and clinical stability was maintained for all implants at 12 months. Although two minor complications were reported — early wound dehiscence and implant exposure in the anterior palate — no major complication required extensive reoperation. This study highlights that the restoration of prosthetic stability remains the key determinant of patient satisfaction, regardless of the type of device used.

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