Dento-craniofacial phenotypes and underlying molecular mechanisms in hypohidrotic ectodermal dysplasia (HED): a review.

The hypohidrotic ectodermal dysplasias (HED) belong to a large and heterogeneous nosological group of polymalfomative syndromes characterized by dystrophy or agenesis of ectodermal derivatives. Molecular etiologies of HED consist of mutations of the genes involved in the Ectodysplasin (EDA)-NF-kappaB pathway. Besides the classic ectodermal signs, craniofacial and bone manifestations are associated with the phenotypic spectrum of HED. The dental phenotype of HED consists of various degrees of oligodontia with other dental abnormalities, and these are important in the early diagnosis and identification of persons with HED. Phenotypic dental markers of heterozygous females for EDA gene mutation-moderate oligodontia, conical incisors, and delayed dental eruption-are important for individuals giving reliable genetic counseling. Some dental ageneses observed in HED are also encountered in non-syndromic oligodontia. These clinical similarities may reflect possible interactions between homeobox genes implicated in early steps of odontogenesis and the Ectodysplasin (EDA)-NF-kappaB pathway. Craniofacial dysmorphologies and bone structural anomalies are also associated with the phenotypic spectrum of persons with HED patients. The corresponding molecular mechanisms involve altered interactions between the EDA-NF-kappaB pathway and signaling molecules essential in skeletogenic neural crest cell differentiation, migration, and osteoclastic differentiation. Regarding oral treatment of persons with HED, implant-supported prostheses are used with a relatively high implant survival rate. Recently, groundbreaking experimental approaches with recombinant EDA or transgenesis of EDA-A1 were developed from the perspective of systemic treatment and appear very promising. All these clinical observations and molecular data allow for the specification of the craniofacial phenotypic spectrum in HED and provide a better understanding of the mechanisms involved in the pathogenesis of this syndrome.

[Evaluation of the Caridex system and its pulp biocompatibility]. / Evaluation du système Caridex et de sa biocompatibilité pulpaire.

A study of the pulpal biocompatibility of the Caridex system was carried out on human premolars to be extracted bilaterally for orthodontic reasons, in 3 volunteers aged 10 to 13 years. A class V cavity was prepared bilaterally on the 2 premolars to be extracted: one of the cavities was washed with Caridex. The other was used as a control. The extractions were made immediately, 4 and 7 weeks after these operative procedures. Histological examinations showed that the Caridex system was biocompatible for the human dental pulp. A comparative study of carious cavities was conducted using light microscopy, Gram stain and transmission electron microscopy on the quality of the cleaning obtained after conventional cavity preparation and use of the Caridex system. After Caridex treatment, the dentinal surface was free of demineralized zones and no smear layer was present. The occasional presence of bacteria was noticed after conventional use of a bur as well as after Caridex. More limited clinical indications of the Caridex system are proposed.