Enamel paint

Biology

Metallurgy

Materials science

Layer (electronics)

Botany

Dentistry

Humanities

Permanent teeth

Deciduous teeth

Crystallite

Dental enamel

Composite material

Smear layer

Medicine

Chemistry

Dentin

Deciduous

Archives of Oral Biology

A study of the outer layer of enamel was made on longitudinal, undecalcified sections prepared from twenty-eight erupted deciduous teeth, eighty-eight erupted and forty unerupted permanent teeth which were examined by means of polarized light and phase contrast microscopy and microradiography. A layer of apparently “prismless” enamel was found on all the deciduous teeth and on 70 per cent of the permanent teeth. This layer, which averaged approximately 30μ in thickness, frequently showed surface parallel laminations and the crystallites within the layer were oriented with their “c” or optic axis almost perpendicular to the enamel surface. For the twenty-eight deciduous teeth, the crystallite orientation of the “prismless” layer differed from that of the underlying enamel by 26.9 ° ± 7.6 °.

The “prismless” outer layer of deciduous and permanent enamel