Scanning electron microscopic study of primary teeth in X-linked amelogenesis imperfecta

Exfoliated primary teeth from a boy and a girl from a family with X-linked amelogenesis imperfecta (XAI) were studied by scanning electron microscopy. Teeth from the boy featured multiple shallow depressions on the enamel surface interspersed with deeper tubular voids. Shallow depressions and similar tubular defects were also apparent in control teeth from an unaffected individual but these were less frequent, irregularly distributed and less marked. Teeth from the heterozygous girl had broad furrows running longitudinally from the cusp(s) of the tooth cervically. These furrows were formed by a series of saucerized depressions which merged together in some areas. The bases of these depressions featured tubular voids extending into the enamel. These similar voids in teeth from both boy and girl probably represent enamel prism spaces vacant because of defective enamel protein synthesis and/or mineralization. Although the scanning electron microscopic features of teeth from females observed in this and previous studies of XAI differ, the enamel appears to be more similar in males with differing clinical XAI phenotypes.