Electron microscopy of surface enamel of human unerupted and erupted teeth.
J Palamara, PP Phakey, WA Rachinger, HJ Orams
Arch Oral Biol | Published : 1980
The ultrastructure of the surface regions were studied using specimens ion-beam thinned from one side only. The crystalline surface of unerupted teeth was composed primarily of small (≈ 10 nm) loosely packed crystals and was overlaid by a primary cuticle which penetrated depressions in the underlying fine crystal layer. Some big (≈ 500 nm) crystals, 50 per cent of which were hydroxyapatite, were found among the small crystals and in the cuticle. The evidence suggested that, following eruption, this primary cuticle and the surface crystalline layer are removed and the coarser sub-surface crystalline layer is exposed to form the new surface typical of erupted teeth. © 1980.