Author :
Dr. Ashwini.B.L, Asst. Professor, College of Dental Sciences

Abstract

Ectodermal dysplasia (ED) is a hereditary disorder characterized by developmental dystrophies of ectodermal derivatives. It is characterized by triad of signs comprising of sparse hair, abnormal/missing teeth and inability to sweat. Oral symptoms of ED include multiple tooth abnormalities (such as hypodontia, anodontia, impacted teeth, and peg-shaped or conical anterior teeth) and lack of normal alveolar ridge development. A 24-year old male patient, in the absence of any other systemic abnormalities, exhibited typical characteristics of  ED, visited our department. In the clinical examination it was revealed that he had 4 teeth in the maxillary arch and 3 teeth in the mandibular arch. Clinical management consisted of removable complete dentures retaining the existing teeth to improve psychological and better functioning of stomatognathic system.

Introduction

Ectodermal dysplasia have been described as a group of disorders of morphogenesis displaying two or more of the symptoms of trichodysplasia, dental anomalies, onychodysplasia, and dyshidrosis1 .  It is usually described as being hypohidrotic or hidrotic, depending upon the degree of sweat gland function. Anhidrotic ectodermal dysplasia is considered to be a triad of hypodontia or anodontia, hypotrichosis, and hypohidrosis, and associated with other components that result from defective development of structures of ectodermal origin 2. Anhidrotic ectodermal dysplasia is X-linked condition, and is found in all races, with an incidence of 1-7 per 1,00,000 live births 3. Affected males usually have prominent supraorbital ridges, frontal bossing, thin eyebrow, fine-linear wrinkles, sparse hair, defective nails, and saddle nose . Due to the altered anatomy in the lower third of the face, they resemble to edentulous old individuals.
Oral characteristics include complete or partial hypodontia, anodontia, impacted teeth, loss of vertical dimensions of occlusion, malformed and peg-shaped or conical teeth, and lack of alveolar growth. Oral symptoms of ED include multiple tooth abnormalities and lack of normal alveolar ridge development  and can complicate the restoration of an ideal occlusion. Lack of alveolar growth frequently results in increased interocclusal distance, which allows optimum artificial tooth placement . This case report emphasizes the prosthodontic management of appearance and function in the form of a complete denture.

Clinical Report

A 24-year old male patient, who reported to department of prosthodontics college of dental sciences, exhibited typical characteristics of  ED, including fine sparse hair, thin eyebrow, fine-linear wrinkles, saddle nose, protuberant lips,  and partial hypodontia . The intra-oral examination revealed the presence of bilateral canines and first  molars in the maxillary arch and 2 retained deciduous incisors and 1 molar in the right quadrant of mandibular arch(fig 1,2). The present canine teeth were conical in shape and he had hypoplastic molars. Radiogragh revealed underdeveloped arches and presence of impacted teeth in the mandibular arch(fig 3). There was no family history of missing teeth, neither with his siblings nor with his parents/grandparents.

The prosthodontics management of patients suffering from ED depends on the degree of anodontia/hypodontia. In complete anodontia, the treatment would comprise of complete dentures, either conventional/implant supported. In patients with partial anodontia, removable/fixed partial dentures and overdentures may be considered. In the present case, a conventional  overdenture was the treatment of choice, because the objective was to preserve the remaining dentition to restore function and esthetics. One important advantage is that overdentures preserve alveolar bone. No copings were given on the teeth present as they were smaller in size with shorter roots. The canines were conical in shape and required no modifications. The molars were restored with composite resin to seal the deep fissures prior to impression making.

Preliminary impressions were made using alginate and stone casts were made. Special trays were fabricated using autopolymerizing acrylic resin, blocking the areas around the teeth with modeling wax. After border molding secondary impressions were made of both the arches using medium viscosity addition silicone and casts were made using type IV dental stone (fig 4) .  Record bases were made and jaw relations registered. An anatomic teeth set was used to obtain balanced occlusion. Trial dentures were checked for retention,stability, phonetics, occlusion, esthetics and VDO. Acrylic dentures were processed with  high impact  heat cure polymethyl methacrylate(Trevalon HI) using compression molding technique. After finishing and polishing overdentures were inserted(fig5,6) .
The patient was was given post insertion instructions on denture wear, functions of speech, mastication, hygiene, and maintenance of remaining teeth using fluoride application. The patient was psychologically pleased with both function and esthetics.

Fig 1: Intraoral view-max arch

Fig 2: Intraoral view-mand arch

Fig 3: Panaromic radiogragh of patient

Fig 4: maxillary and mandibular casts

Fig 5: Finished prosthesis in mouth

Fig 6: Facial view after treatment

Discussion

Hypodontia and anodontia are frequently seen in many cases of ectodermal dysplasia5. Early and extensive dental treatment is needed throughout childhood because of the absence of most of the deciduous and permanent dentition. Fpds and Osseo-integrated implants should be an alternative treatment in older patients with ED 6. A removable partial denture or an overdenture is often a suitable treatment choice, because these treatment options are easy, affordable, and reversible rehabilitation methods. 4
In ED patients, dryness of the oral mucosa and the underdeveloped maxillary tuberosity and alveolar ridges are problematic factors in obtaining retention and stability of dentures. Hence, occlusal load should be distributed over wide area by extending the denture base. The remaining teeth due to their atypical shape not suitable to stabilize RPDs, can be used as abutments for overdentures7. The patient had no appliance worn earlier. The treatment goal was to establish a functional occlusion with prosthetic rehabilitation and to obtain an esthetic smile. This improved the nutrition and  psychological status of the patient.

Conclusion

Prosthetic management of patients with complete/partial anodontia associated with ectodermal dysplasia is important because:

1. It provides good esthetics, phonetics and masticatory comforts.
2. It maintains healthy supporting tissues throughout lifetime of denture-wearing .
3. It helps patients develop good psychologic self-image.

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