Abstract
Rat incisor dentin was studied by polarizing light microscopy, light microscopy, fluorescence microscopy and scanning electron microscopy to investigate the structural differences between labial and lingual dentin.
In lingual dentin, crystals and collagen fibers were regularly arranged, the axis of orientation being parallel to the long axis of the incisor and perpendicular to the dentinal tubules. The crystals appeared to be arranged with inotropic calcification parallel to the long axis of the collagen fibers. In contrast, in labial dentin, crystals and collagen fibers were arranged irregularly, and the crystals showed radial orientation with spheritic calcification. These differences in the crystal and collagen fiber orientation in lingual and labial dentin may possibly arise from different patterns of calcification.
