Case Study On The Ongoing Management Of A Patient Diagnosed With Hypohidrotic Ectodermal Dysplasia

Introduction

Ectodermal dysplasia (ED) is defined by National Foundation for Ectodermal Dysplasia as a large heterogeneous group of inherited disorder that is defined by primary defect in the development of two or more tissues derived from embryonic ectoderm. Freire Maia defined ED as any syndrome that exhibits at least two of the following features: Trichodysplasia (abnormal hairs), abnormal dentition, onchodysplasia (abnormal nails) and dyshidrosis (abnormal or missing sweat glands). Other orofacial characteristic of this syndrome includes anodontia or hypodontia, hypoplastic conical teeth, hypotrichosis, and protuberant lips. Combinations of features were first reported by Danz in 1792. It was also found its mention in Wedderburn’s letter to Charles Darwin in 1838. It was Thurnam who reported hypohidrotic form of ED in 1848. Thadani assigned the X chromosome to have the causative association to ED in 1921. The term hereditary ectodermal dysplasia was coined by Weech in 1929. Felsher suggested the term hypohidrotic in 1944.

Mutations in the ectodysplasin-A and ectodysplasin-A receptor genes are responsible for X-linked and autosomal HED. ED is inherited by autosomal dominant, autosomal-recessive or X-linked genetic transmission. The most frequently reported manifestations of ED are hypohidrotic ectodermal dysplasia (HED) (Christ-Siemens-Touraine syndrome). Hypodontia is known as one of the major factors of ED and is almost always present. These disorders are relatively rare and occur in 1 in 10, 000 to 1 in 100, 000 births.

Dental treatment is often necessary in patients with ectodermal dysplasia and children may need dentures in the early childhood. The remaining teeth should be preserved and modifications should be made in the treatment plan to include them in the intended form of prosthesis. Prosthetic options for management of ED can include fixed, removable or implant supported prosthesis, that may be employed individually or in combination to provide an optimal result.

This case report describes the ongoing management of a 8 year old child diagnosed with hypohidrotic ectodermal dysplasia, who has recently been rehabilitated with Cu Sil denture in maxillary arch and conventional complete denture in mandibular arch.

Case report

A 5 years old male child diagnosed with hypohidrotic ectodermal dysplasia was referred to the Department of Prosthodontics and Crown & Bridge four years ago with the chief complaint of lack of teeth and difficulty in chewing. According to parents, upper arch contained few deciduous teeth initially but exfoliated spontaneously leaving only 55 and 65. The lower arch never contained any tooth. The child was fearful and anxious when he reported to the department but he was conscious, alert. He was moderately built and nourished and his vitals were within normal range. However his parents complained about his intolerability to heat. On physical examination it was found that he had low nasal bridge, pronounced chin, sunken cheeks, prominent and everted cracked lips, circum oral and periorbital hyper pigmentation, sparse, hypopigmented hairs, sparse eyebrows and eye lashes and his skin was dry and scaly. He also had defective fingernails. Intraoral examination revealed absence of all mandibular teeth, presence of teeth numbers 55 and 65 in the maxilla. 55 was carious and exposed. The panoramic radiograph confirmed the absence of retained deciduous teeth and there were no permanent tooth germ in either the maxilla or mandible. Parents were sensitized and counselled about this condition, its maxillofacial and nutritional consequences and the scope of prosthodontic management according to age. The need for multidisciplinary management as also emphasized. As the child was fearful and aversive towards the dental team behavioral modification in the form of desensitisation exercises and oral motor exercises like stretching, massage and vibration palpation and passive range of motion exercises were performed to modulate the child.

Subsequently 55 was extracted after consultation with endodontist and pedodontist. A minimally invasive treatment plan was formulated and the child was rehabilitated with an interim removable partial denture in the maxillary arch and complete denture in the lower arch. One denture at a time was inserted with a gap of two weeks in between so as to enable the child to cope with the new prosthesis. An well-structured follow up plan was devised and the post insertion instructions were provided to the parents. The child was also referred to a speech therapist for articulation training. The prosthesis was adjusted every month for the first 3 months and then half yearly follow up schedule was followed. After four years the child was again re-evaluated for replacement of the prosthesis as he complained the prosthesis to be very loose. The child was calm, conscious and alert this time and co-operated with the dental team. It was found that his profile has been improved in terms of proportional vertical and horizontal growth. His speech was also found to be well articulated. His parents reported that he was well accepted in the among his peers in school without any sign of discrimination. A fresh set of investigations in the form of OPG and CBCT was advised to evaluate the availability of bone in the maxilla and mandibular arch. It was found that 65 was in perfect health. CBCT data showed that there were inadequacy of bone for implant placement in the maxilla and mandible and conventional implants could not be placed without any adjunctive augmentation surgery. Keeping in mind the age of the patient and future compliance towards dental treatment it was decided to undertake removable prostheses in the form of Cu Sil denture in maxillary arch and conventional complete denture in mandibular arch to rehabilitate him at the age 9 years. A preliminary impression was made using stock edentulous tray and putty consistency polyvinyl siloxane impression material.

The final impression was made with a custom tray fabricated with autopolymerizing acrylic resin and border-moulded with the help of green stick impression compound. Final impression was made subsequently with light body consistency polyvinyl siloxane impression material. Master casts were poured using type III dental stone. They were mounted on a Hanau wide vue semi-adjustable articulator with a Hanau spring bow arbitrary facebow instrument, using condylar guidance of 30∘, Bennett angle of 15∘ and standard intercondylar distance (110 mm). Occlusal vertical dimension was established using the physiological rest position associated with phonetic and esthetic. Centric occlusion was established according to dynamic records based on unforced movements of the jaws in the terminal hinge position performed by the patients under the supervision and manual guidance. The artificial teeth were arranged in wax occlusion rims and trial was taken. The denture was fabricated in centric occlusion with balanced articulation and anatomically shaped acrylic teeth with a cuspal inclination of 33. The patient and his parents accepted the arrangement of teeth. The dentures were waxed, processed, finished and polished. A silicone ring was provided around the 65 to maintain the peripheral seal and to aid in comfort to the patient. Following denture insertion, the child and parents were counseled about its use, cleaning procedures and the importance of follow up. The patient was monitored for verification of improvement in physical and emotional state, with appropriate adaptation to new denture and subsequent progress in speech and esthetics. Future recall was also planned at 6 months to monitor bone growth and for eventual relining or construction of a new denture.

Discussion

The main objectives of prosthodontic rehabilitation in patients with ED are to improve the esthetics, phonetics and masticatory function thereby ensuring the overall psychosocial wellbeing of the individual. Prostheses also improve the tone of the muscles of mastication and compensate for the reduced vertical dimension. It is more important for a child so as to enable the individual to develop physically, emotionally and socially like other healthy children. It is imperative to prepare a long-term treatment plan that includes regular reviews to ensure that the patient with ED maintains an adequate level of oral health care. The successful use of any prosthesis depends on the cooperation and communication between members of the multidisciplinary team and the patient. Nowak stated that “treating the pediatric patient with ED requires the clinician to be knowledgeable in growth and development, behavioral management, techniques in the fabrication of prosthesis, the ability to motivate the patient and parents in the use of the prosthesis, and the long-term follow-up for the modification and/or replacement of the prosthesis. ” Till and Marques emphasized the requirement of an initial prosthesis to be delivered before the child begins school so that the child has a normal appearance and time to adapt to the prosthesis. Ultimately, the decision to commence the treatment should be planned by the treating prosthodontist along with the parents and patient.

Prosthodontic rehabilitation for an ED patient consists of various combinations of overdenture, complete or partial removable prostheses, fixed dental prostheses and implant prostheses. Removable prosthesis is the most frequently reported treatment modality for the dental management of ED. In the present case, the decision to rehabilitate the child with removable prosthesis was made initially as the primary management strategy because it enabled easy modification of the prosthesis during rapid growth periods. It also offered the ED patient and his family an easy, affordable and reversible method of oral rehabilitation. Cooperation of the patient as well as the support of the family made the rehabilitation outcome successful. The child became more cooperative towards the dental team in the past 4 years and complied with the follow up schedule efficiently. The need to change the prosthesis has been attributed to the continual jaw growth. The present rehabilitation strategy of providing a Cusil denture in the maxillary arch stems from the salient advantages of preserving the natural teeth. Natural teeth preserves the alveolar bone, proprioceptive feedback maintaining postural positional relationship of jaws, offered improved retention through the silicone ring. Also the retained teeth can be used to develop a future implant site in the strategic maxillary first molar region.

The use of endosteal implants have gained wide acceptance in the prosthodontic management of ED. Ekstrand and Thomsson, Bergendal et al. , Smith et al, and Cronin et al. have reported situations where endosteal implants were successfully used in the prosthodontic management of ED. A number of studies indicate an improvement in the physiologic and psychologic function of patients with an implant supported denture when compared with their condition before implants were placed or to an edentulous control group with complete dentures.

UCSF has developed an useful classification system to simplify the protocol to be followed while considering implant therapy in the young patients afflicted with Ectodermal dysplasia.

• Group-1: Missing single tooth with permanent teeth adjacent to the site - To be restored by transitional prosthesis until growth is complete.
• Group-2: Missing multiple teeth anteriorly or posteriorly with permanent teeth adjacent to the edentulous areas - Advised to wait until growth is complete but implants can be considered in selected patients before the cessation of growth.
• Group-3: Essentially edentulous - Implants are indicated at an early age if the patient has the potential to be compliant.

However, According to Cronin et al. possible consequences of early implant placement include implant submergence because of jaw growth, implant exposure because of bone resorption associated with jaw growth, implant movement because of jaw growth and limitation of jaw growth if the implants are connected by a rigid prosthesis that crosses the midline. When implant placement in young ED patients is being considered, their dental and skeletal maturity, not their chronological age, should be the determining factor. Lekholm concurs with criteria concerning maximum jaw growth, giving age guidelines of 14-15 years of age for girls and a year later for boys. He also recommends that an individual’s growth curve be studied before any implant placement procedure is started. According to Mackie and Quayle implant placement in children younger than 16-18 years must be avoided or they will remain in infra-occlusion due to adjacent alveolar bone growth.

The use of conventional removable prostheses before undergoing invasive implant therapy is recommended. It helps to condition the growing child and provides esthetic and functional information for the subsequent implant treatment planning. The use of a conventional prosthesis is also important until the patient achieves a more appropriate level of maturity. It is to be kept in mind that an ED patient requires a life time commitment in terms of dental treatment which is ongoing, progressive and sometimes cumulative in nature. So injudicious and overzealous invasive treatment may predispose a child to become antipathic towards the dental team and can have serious negative impact on the future compliance and outcome of dental therapy.

Conclusion

Individuals affected by ED face a lifetime of special needs, which may include dentures at a young age with frequent adjustments and replacements, special diets to meet dental/nutritional needs, air-conditioned environments, wigs to conceal hair and scalp conditions, carrier identification testing, protective devices from direct sunlight, osseointegrated dental implants and respiratory and speech therapy. The ultimate success of the treatment depends on active participation and cooperation of the patient and family members. A responsible clinician should thoroughly explain the issues and responsibilities involved in the long treatment process so as to make the rehabilitation smooth and successful.