Coronal dentinal tubules of non-erupted deciduous incisors.

The diameter and density of coronal dentinal tubules were assessed in non-erupted human deciduous incisors. Using liquid nitrogen, frozen samples were fractured in longitudinal and oblique directions and observed by means of a Jeol JSM-6100 scanning electron microscope. It was observed that the diameter of dentinal tubules ranged from 0.50 to 1.94 micrometers and increased significantly from the outer to the inner layers. However, comparing the incisal, middle and cervical thirds, no statistically significant differences were observed. The number of tubules per square millimeter varied from 3,281 to 32,313 and also increased from the external dentinal surface to the dentinal surface of the pulp chamber.