Giacomo De Riu, MD, FEBOMFS1, Andrea Biglio, MD, DDS1, Giovanni Spano, DDS2, Giuseppe Consorti, DDS3,4,
Jerome R Lechien, MD, PhD, FACS5,6 and Luigi Angelo Vaira, MD, PhD1
Abstract
Ectrodactyly-ectodermal dysplasia-cleft (EEC) syndrome is a rare genetic disorder presenting signi cant challenges for dental
rehabilitation due to severe maxillary atrophy and altered anatomy. This report describes a 23-year-old female with EEC syn-
drome successfully rehabilitated using a custom-made subperiosteal implant. Despite multiple grafting procedures, conventional
implants were not viable. A computer-aided design/computer-aided manufacturing-designed, laser-melted titanium subperiosteal
implant was planned based on the cone beam computed tomography imaging and digital scans, ensuring optimal adaptation. At 18
months postsurgery, the implant remained stable, with no complications. This case highlights the potential of modern subper-
iosteal implants as a viable alternative for complex craniofacial reconstructions.
Introduction
Ectrodactyly-ectodermal dysplasia-cleft (EEC) syndrome is a rare genetic disorder, with an estimated prevalence of approx-imately 1 in 90 000 live births, characterized by a triad of limb malformations, abnormalities in ectoderm-derived tissues, and orofacial clefting.
Dental manifestations often include hypodontia, conical-shaped teeth, and fragile enamel, leading to signi cant functional and esthetic impairments.
These dentalanomalies have profound implications on a young patient’s quality of life, impacting their ability to chew effectively, speak clearly, and develop normal psychosocial interactions.
Dental rehabilitation in patients with EEC syndrome is particularly challenging due to the compromised bone volume, altered maxillofacial anatomy, and unusual tooth con gurations that limit conventional treatment options.
The combination of congenital defects, early tooth loss, and the need for long-term prosthetic management demands a carefully tailored and interdisciplinary approach Given these complexities, standard
implant-supported restorations may be dif cult to achieve or maintain, requiring alternative solutions that can provide stable, functional, and esthetically acceptable outcomes. Subperiosteal implants wererst introduced in the 1940s by Dahl and later popularized by Goldberg and Gershkoff in 1949. Initially, they were considered a promising solution for edentulous patients with severe maxillary or mandibular Maxillofacial Surgery Operative Unit, Department of Medicine, Surgery and Pharmacy, University of Sassari, Sassari, Italy Dental School, University Hospital of Sassari, Sassari, Italy Division of Maxillofacial Surgery, Department of Neurological Sciences, Marche University Hospitals-Umberto I, Ancona, Italy Department of Biomedical Sciences and Public Health, Polytechnic University of Marche, Ancona, Italy Department of Surgery, Mons School of Medicine, UMONS, Research Institute for Health Sciences and Technology, University of Mons (UMons),Mons, Belgium Department of Otolaryngology-Head Neck Surgery, Elsan Polyclinic of Poitiers, Poitiers, France.
Subperiosteal implants were historically used to address severe jawbone atrophy when traditional bone grafting or endosseous implants were not viable options. Early designs featured cobalt-chromium frameworks custom-fitted to the bone and anchored beneath the periosteum. However, due to poor osseointegration, these early implants often led to complications such as infections, chronic inflammation, and bone resorption, resulting in survival rates of only 50–60% after 15 years. Many required early removal due to persistent issues.
With the rise of osseointegrated endosseous implants in the late 20th century—which offered superior long-term results—subperiosteal implants fell out of favor. However, recent advancements in CAD/CAM technology and 3D laser melting have revived their use for complex cases, including severely atrophic jaws and post-resection defects. Modern subperiosteal implants are now custom-designed using precise CT-based digital planning, ensuring better fit, stability, and long-term success.
Case Presentation: Successful Rehabilitation in EEC Syndrome
A young female patient with Ectrodactyly-Ectodermal Dysplasia-Clefting (EEC) syndrome presented with severe maxillary retrusion, transverse deficiency, and bilateral hard palate clefts. After multiple reconstructive surgeries (including bone grafting and maxillary expansion), she still lacked sufficient bone for traditional implants.
Using CBCT-guided 3D modeling, custom subperiosteal implants were designed with supporting arms along the nasomaxillary and zygomatic pillars for optimal stability. The implants featured multi-unit abutments (MUA) to minimize bone loss and were secured with screws in areas of maximum bone thickness (4.5–12 mm).This approach—supported by finite element analysis—allowed for successful prosthetic rehabilitation, demonstrating the potential of modern subperiosteal implants in complex craniofacial cases.
Figure 1. Preoperative Frontal (A) and Lateral (B) Views of the Patient Affected by EEC Syndrome, Illustrating Nasal Deformity, Cleft Lip, and
Maxillary Hypoplasia. The Lateral Perspective Highlights the Reduced Maxillary Projection and Altered Midfacial Morphology. Abbreviation:
EEC, ectrodactyly-ectodermal dysplasia-cleft.
minimizes maxillary periosteal elevation, avoids palatal mucosa detachment and nasopalatine nerve sacrifice, and enhances prosthetic fit by preventing cumulative discrepancies. Furthermore, in case of infection or complications affecting one side, treatment can be isolated without compromising the entire rehabilitation.
A cobalt-chrome surgical guide was fabricated to assist in preparing the alveolar crest slots accurately. The final 3D models of the bone, soft tissues, planned prostheses, and the implant itself were reviewed within the GS software. After the surgeon’s approval, the implant frameworks were manufactured from grade V titanium (Ti-6Al-4V) using a double laser melting process (MYSINT100, Sisma, Piovene Rocchette, Italy). The transmucosal portions of the titanium framework were polished to minimize soft tissue irritation and reduce plaque accumulation, thereby lowering the risk of peri-implant complications. Conversely, the subperiosteal portions of the framework featured a microtextured surface to enhance mechanical stability and promote better adaptation to the underlying bone.
The surgery was performed under local anesthesia supplemented with superficial intravenous sedation using diazepam. Local anesthesia was administered with articaine containing 1:100,000 adrenaline. Anesthesia for the upper anterior surgical area was achieved via an extraoral block of the infraorbital and zygomatic nerves. Intraoral anesthesia was applied to the upper vestibular fornix and, on the palatal side, by blocking the greater palatine and nasopalatine nerves.
A full-thickness mucosal incision was created along the alveolar crest with 2 releasing incisions, one on the midline and the other at least 5 mm away from the most distal abutment. The incision was made 2 to 3 mm palatally to ensure that an adequate amount of keratinized gingiva could be repositioned to the vestibular side of the abutments. A full-thickness flap was elevated on both the vestibular and palatal sides. Using the crestal template, slots for the abutment housings were prepared, extending to the basal bone as needed.
After preparing the alveolar crest, additional dissection exposed the upper maxilla, allowing for the identification and preservation of the infraorbital nerve and the full exposure of the nasomaxillary pillar and zygomatic buttress. The custom subperiosteal implant was then positioned, and its fit was verified. Rigid fixation was achieved using grade V titanium osteosynthesis screws (B&B Dental, San Pietro in Casale, Italy) with a 2 mm diameter (Figure 3A and B). Once the implant was fixed, it was covered with collagen membranes to thicken the soft tissue over the implant and prevent exposure (Figure 3C and D). In this case, the buccal fat pad was not utilized for soft tissue coverage due to the patient’s limited buccal fat volume and the already reduced buccal vestibule caused by severe maxillary atrophy. Using the buccal fat pad would have further compromised the prosthetic fit by decreasing the available space for the prosthesis. The mucosal flap was passivated using periosteal releases and carefully sutured.
Antibiotic therapy with amoxicillin and clavulanic acid (1 g twice daily for 6 days) was prescribed, along with medications for pain management. The patient underwent immediate.
Figure 2. (A) Preoperative CBCT Cross-Sectional Views of the Maxilla Illustrating Severely Reduced Bone Volume. (B) Three-Dimensional
Reconstruction Displaying the Custom-Designed Subperiosteal Implants, Adapted to the Patient’s Anatomy and Anchored Along the
Nasomaxillary and Maxillomalar Pillars. Abbreviation: CBCT, cone beam computed tomography.
Loading with a xed provisional prosthesis secured to the MUA. The provisional prosthesis consisted of a resin-based structure supported by a bar. The screw-retained de nitive prosthesis, consisting in a milled titanium bar with layered composite framework was delivered 6 months later, after adequate soft tissue healing and conditioning (Figure 4). A xed prosthetic solution was selected over a removable alternative to maximize stability and function, particularly in light of the patient’s reduced vestibular depth and retrognathic maxilla. A rigorous hygiene protocol was followed, including professional cleaning every 3 months with prosthesis removal every 6 months for decontamination. The patient was instructed to maintain meticulous oral hygiene using an oral irrigator and interdental brushes to prevent bio lm accumulation and soft tissue in ammation. At 18 months postsurgery, the subperiosteal implant remains stable, with no signs of exposure, no bleeding on probing or other soft tissue complications, or issues related to the prosthetic rehabilitation (Figure 5).
Discussion
EEC syndrome presents a particularly challenging scenario for dental rehabilitation due to the complex interplay of congenital craniofacial anomalies, compromised bone volume, and altered dental anatomies.1,2 Conventional implant-based solutions often prove inadequate, as limited bone stock and abnormal maxillary morphology can hamper the placement and long-term stability of standard endosseous implants.3,4 Moreover, multiple surgical interventions performed during growth to correct cleft-related deformities, as in this case, may further reduce bone availability and complicate subsequent prosthetic rehabilitation.22 Recent advancements in technology have led to the reintroduction of subperiosteal implants as an effective treatment alternative for severely atrophic jaws or complex craniofacial defects.8-13 In contrast to traditional implant systems, subperiosteal implants rest directly on the bone surface, eliminating the need for extensive bone grafting or sinus elevations. With the incorporation of CAD/CAM work ows, high-resolution CBCT imaging, and precision manufacturing methods such as laser melting, additively manufactured custom-made subperiosteal implants are more predictable, better adapted to patient-speci c anatomies, and offer improved biomechanical characteristics.17-20,23 It should be noted, however, that while clinical outcomes appear favorable, there is currently no evidence that custom-made subperiosteal implants achieve osseointegration.
Figure 3. (A) and (B) Intraoperative View of the Custom-Made Subperiosteal Implant Positioned and Stabilized with Titanium Screws,
Featuring Integrated Multiunit Abutments (MUA). (C) and (D) Placement of Collagen Membranes Over the Implant Framework to Enhance Soft
Tissue Thickness and Minimize the Risk of Exposure Before Flap Closure.
Figure 4. Intraoral View at 16 Months Postsurgery Showing the De nitive Fixed Prosthesis Supported by the Subperiosteal Implant.
In this patient with EEC syndrome, the use of a custom subperiosteal implant represented a tailored solution to overcome the limitations imposed by a severely atrophic and previously grafted maxilla. By integrating digital scans, CBCT data, and a diagnostic wax-up, the implant could be designed and fabricated with precise 3D accuracy. The resulting framework was
Figure 5. Postoperative Frontal (A) and Lateral (B) Views at 16 Months, Demonstrating Improved Facial Esthetics, Stable Occlusion, and
Satisfactory Soft Tissue Contour Following Maxillary Rehabilitation with Custom-Made Subperiosteal Implants.
well adapted to the bony contours, provided adequate support for immediate loading, and facilitated a favorable esthetic and functional outcome. The addition of collagen membranes and careful soft tissue management helped ensure stable soft tissue coverage, minimizing the risk of exposure—a complication historically associated with subperiosteal implants.
Conclusions
This report present a patient with EEC syndrome rehabilitated using modern custom-made subperiosteal implants. The stability observed at 18 months postsurgery, with no soft tissue or prosthetic complications, underscores the potential of this approach for similarly complex craniofacial conditions.
Further research and long-term follow up are needed to establish standardized protocols, understand the factors in uencing long-term survival, and fully delineate the role of subperiosteal implants in the rehabilitation of patients with EEC syndrome and other complex congenital anomalies. As technology continues to advance, it is likely that custom-designed implant solutions will become more accessible, ultimately improving treatment outcomes and quality of life for patients facing severe craniofacial challenges.