Structural and compositional alteration of tooth enamel in hereditary epidermolysis bullosa.

Epidermolysis bullosa (EB) is a group of conditions characterized by basement membrane and cellular defects that result in skin fragility and variable extra-cutaneous involvement. The teeth can be severely affected with marked enamel malformations. The purpose of this study was to characterize the structure and composition of teeth from individuals representing the major EB groups (EB simplex, dystrophic EB and junctional EB). Teeth were examined from 28 individuals with EB and 10 healthy people unaffected by EB. Teeth from individuals with junctional EB had marked enamel hypoplasia with varying abnormalities in the enamel structure. Minor structural defects of enamel, including areas of surface pitting, were seen in the other EB types. Although there was a slight reduction (approximately 10%) in the enamel mineral content in several dystrophic EB and junctional EB teeth, the mean mineral content was similar for all EB enamel types and normal enamel. This study shows that while individuals with junctional EB have marked alteration of the enamel structure, the composition may be normal to only mildly altered. Laminin-5, the molecular defect in junctional EB, is associated primarily with alteration in the amount and/or structure of enamel while the mineralization process appears relatively intact. The marked enamel hypoplasia in this EB type suggests that laminin-5 plays an important role in the secretory phase of enamel development.