The challenge of global rehabilitation in cases of ectodermal dysplasia

Ectodermal dysplasia (ED) presents the practitioner with major anatomical complexities: severe oligodontia, hypoplastic alveolar ridges, and collapse of the vertical dimension of occlusion (VDO). This case report describes the multidisciplinary management of a 21-year-old patient presenting with multiple agenesis (notably 12, 13, 14, 22, 23, 24 in the maxilla and 31, 32, 33, 34, 36, 41, 42, 43, 44 in the mandible) associated with "peg-shaped" central incisors.

L’objectif de cette étude est de démontrer l’efficacité d’un flux de travail numérique — intégrant l’analyse CBCT et des guides chirurgicaux imprimés en 3D — pour sécuriser la pose d'implants dans une mandibule aux volumes osseux réduits, tout en restaurant la fonction par une approche prothétique pilotée par le résultat final.

The strategy is based on the hypothesis that a hybrid rehabilitation, combining a tooth-supported telescopic overdenture in the maxilla and an implant-supported prosthesis in the mandible, allows for the compensation of ridge atrophy and the stabilization of occlusion at a VDO increased by 4 mm. This protocol aims to validate the predictability of CAD/CAM and DMLS technologies in the management of complex congenital anomalies.

Methodology of the clinical case

This case report documents the global rehabilitation of a 21-year-old female patient diagnosed with ectodermal dysplasia. The diagnostic protocol was based on clinical evaluation and a positive family history. Intra-oral examination revealed severe oligodontia, with the congenital absence of teeth 12, 13, 14, 22, 23, and 24 in the maxilla, as well as teeth 31, 32, 33, 34, 36, 41, 42, 43, and 44 in the mandible. The maxillary central incisors (11 and 21) exhibited a characteristic conical shape.

• Digital planning and imaging: A cone beam computed tomography (CBCT) analysis was performed to evaluate the mandibular bone morphology. The measurements recorded in the interforaminal region indicated a height/width of 17.4/5.6 mm (site 44), 19.6/5.8 mm (site 42), 16.4/5.6 mm (site 34) and 18.5/4.7 mm (site 32).
• Surgical protocol: A 3D-printed surgical guide was designed from a radiographic stent. After reflection of a full-thickness mucoperiosteal flap, 5 endosseous implants (Osstem TSIII, diameter 3.5 mm, length 10 mm) were placed under digital guidance. Primary stability was achieved by manual application of a torque wrench.
• Rehabilitation strategy: The treatment plan integrated a 4 mm increase in the vertical dimension of occlusion (VDO), validated by a provisional phase. The final restoration included a tooth-supported telescopic overdenture in the maxilla (using the remaining natural teeth as abutments) and an implant-supported hybrid prosthesis in the mandible covering the 44-34 area.

Results of prosthetic and implant rehabilitation

The initial clinical evaluation of this 21-year-old patient revealed severe oligodontia and conoid maxillary central incisors (11 and 21), characteristic of ectodermal dysplasia. The examination showed a reduced vertical dimension of occlusion (VDO) and underdeveloped alveolar ridges. A 4 mm increase in VDO was planned and successfully tested using a diagnostic removable prosthesis and provisional crowns to validate aesthetics and function.

Bone morphometric analysis

Cone beam computed tomography (CBCT) imaging has allowed for the precise quantification of bone availability in the mandibular interforaminal region. The measurements recorded at the four planned implant sites are as follows:

Surgical implementation and stability

Digital planning resulted in the placement of four implants (Osstem TSIII) with a diameter of 3.5 mm and a length of 10 mm. The use of a 3D-printed surgical guide ensured the precise transfer of the planned position to the surgical field. Primary stability was manually confirmed during implant placement with a torque wrench.

The multidisciplinary approach allowed for the restoration of facial aesthetics, lip support, and occlusal balance. The shortened dental arch concept was applied to optimize functional efficiency while respecting the patient's anatomical constraints. Qualitative results show a significant improvement in masticatory performance and overall patient satisfaction.

The contribution of digital workflow and telescopic prosthetics

The success of this rehabilitation is based on rigorous management of the vertical dimension of occlusion (VDO), increased here by 4 mm to restore facial harmony and masticatory efficiency. The use of a telescopic prosthesis in the maxilla is a major strategic choice: it allows for the preservation of the remaining permanent teeth, including the conoid incisors 11 and 21, by transforming them into support pillars. This approach preserves the bone capital and optimizes proprioception, an undeniable clinical advantage compared to the systematic extraction often considered in cases of ectodermal dysplasia (ED).

Technically, mandibular implant planning illustrates the precision of the digital workflow. Although the source contains a textual inaccuracy mentioning "five sites" while only four are documented and measured (34, 32, 42, and 44), the use of a 3D-printed surgical guide allowed for secure placement despite alveolar ridge atrophy. The use of porcelain-fused-to-metal (PFM) crowns and a cobalt-chrome framework produced via direct metal laser sintering (DMLS) ensures robust prosthetic stability.

However, one limitation deserves to be highlighted: the lack of long-term clinical follow-up in this report. While the immediate results show a significant improvement in quality of life, the durability of telescopic abutments on malformed teeth remains a point of vigilance for the practitioner. This case nevertheless confirms that a multidisciplinary approach — combining sophisticated removable prosthetics and guided implantology — is the key to success for these young patients with complex anatomical challenges.

Summary of results

This multidisciplinary rehabilitation in a 21-year-old patient validated a 4 mm increase in the vertical dimension of occlusion (VDO) via a full digital workflow. The mandibular implantation of four 3.5 mm diameter abutments on narrow ridges (up to 4.7 mm wide) allowed for a stable hybrid restoration, confirmed after 4 months of healing.

In concrete terms, for the practitioner:

• Master ridge-to-implant ratios: On undersized ridges (4.7 mm), the use of 3.5 mm diameter implants is viable, provided a 3D surgical guide is used to ensure ultra-precise positioning and avoid fenestrations.
• Adopt the SDA (Shortened Dental Arch) concept: For these complex cases, prioritize a functional shortened dental arch that simplifies prosthetic biomechanics while ensuring occlusal stability and satisfactory masticatory efficiency.
• Leverage telescopic anchors: In the presence of dysplastic teeth (peg-shaped incisors), the maxillary telescopic overdenture is a solution of choice for managing aesthetics and access to hygiene, compared to a conventional fixed prosthesis.

Technical lexicon of rehabilitation

Ectodermal dysplasia (ED): Hereditary pathology characterized by developmental anomalies of ectodermal structures. In this clinical case, it manifests as severe oligodontia, conical teeth, and marked hypoplasia of the alveolar ridges.

Peg-shaped teeth: Morphological anomaly (microdontia) making the teeth conical. The study identifies the maxillary central incisors (11 and 21) as such, subsequently using them as prosthetic abutments.

Vertical Dimension of Occlusion (VDO): Facial height measured during occlusal contact. Strategic choice to increase it by 4 mm in this protocol to restore the patient's facial aesthetics and occlusal balance.

Reduced dental arch concept: Therapeutic approach focused on functional efficiency and occlusal stability with a limited number of teeth, applied here to simplify rehabilitation while ensuring masticatory comfort.

Telescopic overdenture: Tooth-supported removable prosthesis using a double crown system (primary and secondary copings) on the remaining teeth (11, 21, 15, 16, 25, 26). This system optimizes support and hygienic maintenance.

CAD/CAM: Digital workflow including computer-aided design and manufacturing. These technologies have been mobilised to improve the predictability of prosthetic results and the precision of surgical devices.

3D-printed surgical guide: Precision device designed from CBCT analysis and virtual prosthetic planning, allowing for rigorous implant positioning in the mandibular interforaminal region.

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