Tricho-dento-osseous syndrome: a scanning electron microscopic analysis.

A large kindred of which multiple members have the Tricho-dento-osseous syndrome is presented. This is an autosomal dominant disorder characterized by defective enamel, taurodontia, unusually curly hair and occasionally mild to moderate skeletal osteosclerosis. Histologic investigation of teeth (by both LM and SEM) demonstrated that there is a uniformly thin enamel covering with randomly distributed depression and pits. The mineral content of this enamel is closer to that of the underlying dentin, which accounts for its lack of radiographic contrast. The dentin was normal. A bizarre finding is that of a periradicular sheath or membrane that enclosed the open apices and extended partway up the root. It was composed of collagen fiber bundles. The anatomical position of this membrane suggested that it may represent the developing peridontal ligament seen in early tooth formation. Recent embryologic evidence provides support for mesenchymal culpability for all reported features of the syndrome.