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Enamel Histology of the Teeth
06-11-2008
Enamel content is almost 100% mineral, so it evades histologic evaluation in common paraffin sections from decalcified material. Only in immature tooth tissues, may it be seen in routinely prepared histologic slides due to a still higher proportion of organic components, where it is visible as a slightly basophilic the ready material. In this form, it may also form part of the histologic appearance of odontogenic tumours.
Examination of mature enamel requires the employment of ground sections. In transmitted
light, incremental lines can be seen in the enamel lying more or less parallel to the crown surface and the dentino-enamel junction, the so-called striae of Retzius. In reflected light, alternating light and dark bands that run perpendicular to the dentino-enamel junction can be observed.
These so-called Hunter-Schreger bands are an optical phenomenon caused by different directions
of the rods that form the building stones of the enamel. These rods have on transverse sectioning the outline of a keyhole. Through interlocking of these rods, a compact structure is formed. Each rod is formed by four ameloblasts.
Te rods are responsible for the striated appearance that immature enamel matrix shows in de-
calcified paraffin sections.
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