Rehabilitation of medically complex ectodermal dysplasia with novel surgical and prosthodontic protocols

Abstract

The functional and aesthetic needs of a 17-year-old patient afflicted with ectodermal dysplasia, chronic long-term immunosuppression, cleft palate, velopharyngeal insufficiency, hypernasality, maxillary hypoplasia, and oligodontia were met with a multidisciplinary team approach. Predictable functional and aesthetic outcomes were obtained with a combination of injection augmentation of the soft palate and nasopharynx and rigid fixation maxillary external distraction with immediate placement and immediate load protocols. No biological or prosthetic complications were noted after definitive rehabilitation with a mandibular implant-retained fixed prosthesis and a maxillary implant-retained detachable prosthesis.

Introduction

Implant survival rates of 91.3–97.6% have been reported in the mandibular rehabilitation of ectodermal dysplasia (ED) patients when a conventional, two-stage approach, implant-supported prosthesis is used.

Hypodontia and anodontia are considered to compromise bone growth, affecting the process of osseointegration. In a study of implants placed in children with ED, major risk factors to successful osseointegration were considered to be low quantity of bone, small dimensions of the mandible, dense cortical bone, and loose cancellous bone.

An evaluation of bone microarchitecture in the mandibles of ED patients demonstrated a greater trabecular bone connectedness in areas of congenital absence of all teeth compared to areas of up to six teeth missing, which may afford a better resistance to functional loading.

The hypoplastic maxilla poses a major functional and aesthetic challenge. This can be repaired by maxillary advancement through conventional surgical methods including Le Fort I–III, and often requires multiple subsequent surgeries. In cases requiring larger skeletal advancement (more than 10 mm) and soft tissue volume in multiple planes, craniomaxillofacial distraction osteogenesis is considered the primary treatment choice. External distraction provides better three-dimensional control of the distraction process, a shorter intraoperative time, and no major operation for device component removal, but has a higher demand with regard to patient compliance. Disadvantages include scarring and infection of the skin around the fixation pins, pin loosening, and intracranial pin migration.

Recently, hyaluronan-based compounds (Deflux; Q-Med, Uppsala, Sweden) have been considered for use as space fillers for posterior pharyngeal wall augmentation.

Multidisciplinary treatment of a medically complex ED case is presented. Based on recent research findings and careful treatment planning, external distraction osteogenesis was combined with immediate implant placement and immediate load protocols to provide predictable treatment.

Materials and methods

In 2010, a 17-year-old Caucasian male presented to the Division of Prosthetic and Aesthetic Dentistry and the Division of Oral and Maxillofacial Surgery for multidisciplinary care. The patient presented with an established diagnosis of ED; a cleft palate had been repaired at another medical centre when the patient was aged 18 months. The medical history was significant for a living donor right kidney transplant at 15 years of age for end-stage renal failure secondary to multicystic dysplasia. The patient was on immunosuppression therapy, which was very well controlled by the transplant team with target levels for immunosuppression with cyclosporine and prednisone. Additional diagnoses included severe maxillary hypoplasia, hypodontia, velopharyngeal insufficiency, non-restorable caries, and generalized moderate periodontitis ( Fig. 1 a). The patient’s medications included allopurinol, atorvastatin, calcium, vitamin D3, cyclosporine, gabapentin, prednisone, bupropion hydrochloride, and sertraline hydrochloride. The clinical presentation was consistent with a diagnosis of ED and cleft palate; it included sparse hair, intolerance to light, hypodontia, and maxillary hypoplasia.

Fig. 1
Patient from initial presentation to treatment and final rehabilitation.

Treatment planning included a staged approach. It started with the off-label use of a filler injection in the nasopharynx and soft palate to treat the velopharyngeal insufficiency and hypernasality. A paediatric distal chip scope was passed transnasally. A total of 6 ml of off-label filler (Deflux; Q-Med, Uppsala, Sweden) was injected into the soft palate and posterior pharyngeal wall.

Clinical and radiographic assessment of the maxilla revealed the need for a significant anterior and vertical advancement. Due to the magnitude of correction required, traditional orthognathic surgery was not performed, but rather a high Le Fort I osteotomy was coupled with the application of a RED device (KLS Martin, Jacksonville, FL) to allow for distraction osteogenesis ( Fig. 1 b). External distraction osteogenesis was initiated 5 days after device placement at two full revolutions of the anterior ports in a clockwise fashion and two full revolutions of the vertical port in a counterclockwise fashion for 30 days. This was followed by an additional 7 days of distraction with 1 mm distraction for the first 3 days and 0.5 mm distraction for the remaining 4 days. The distraction process was not associated with any complications. The consolidation phase lasted for 3 months. A total of 25 mm of anterior–posterior and 5 mm of vertical displacement were achieved.

Post distraction, the patient underwent prosthetic presurgical planning, which revealed the need for a mandibular alveoloplasty. This was completed at the time of dental implant placement to accommodate prosthetic and implant components. The intraoral distractor components were removed, and this was followed by full mouth edentulation, alveoloplasty of the mandible, and the placement of a total of eight dental implants (Mark III TiUnite; Nobel Biocare, Yorba Linda, CA, USA) in the maxilla and six implants in the mandible ( Fig. 1 c). Primary stability to greater than 35 N cm was achieved with all mandibular implants. A prefabricated mandibular complete denture was used as an implant positioning guide during implant placement and was subsequently converted to a fixed implant-supported prosthesis, which was immediately loaded on the same day as the surgery.

A two-stage approach was taken for the maxillary implants. The patient underwent uneventful healing for 6 months, uncovering of the maxillary implants, and definitive prosthetic rehabilitation ( Fig. 1 d). Fig. 2 a and b show preoperative and postoperative lateral cephalometric views, respectively. Facial skeletal and soft tissue changes in frontal and lateral views are shown in Fig. 2 c–f, respectively.

Fig. 2
Facial and radiographic changes before and after treatment.

Due to the limited inter-arch distance even after aggressive mandibular alveoloplasty, the mandibular arch was rehabilitated with a metal ceramic fixed prosthesis. The maxillary arch was rehabilitated with an implant-supported overdenture with a primary bar and a metal acrylic overdenture to replace missing dentition and provide lip support. The multidisciplinary approach to his care resulted in both his aesthetic and functional needs being met.

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Jan 21, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Rehabilitation of medically complex ectodermal dysplasia with novel surgical and prosthodontic protocols
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