[The brown line of Retzius in scanning electron microscopy]

A study in scanning electron microscopy of the striae of Retzius of human enamel, on longitudinal and transverse sections, has shown thin striae and relatively broad bands. The thin striae of Retzius consisted in narrow zones devoided of mineral material which extended obliquely through the prisms. These latter were interrupted at the level of the striae. A thin dense layer bordered sometimes unilaterally the striae of Retzius. The relatively large band-like structures involved several prism rows and can be considered as hypomineralized enamel.