Title: Enamel 3 in longitudinal section of tooth
Thin ground section, human adult. At the left side surface of enamel in cuspal region; the parallel horizontal arrangement of stacks of rods (prisms) is evident. At the right side the dark area of dentin. In the enamel incremental lines (striae) of Retzius run as curved lines (from bottom to middle top) and presented successive apposition of layers of enamel. Hunter-Schreger bands (lines) cross diagonally from the top right side towards the middle half of the enamel. These light and dark strips originate at the dentinoenamel junction and are the result of the change in direction of enamel prisms as well as a different content in organic material in light/dark zones.
At the bottom and the top two long dark stained cracks.
Title: Enamel 5 in longitudinal section of tooth
Thin ground section, polarizing microscopy (optical axes of the polarizing plates are crossed at 60°), human adult.
Using polarizing microscopy the birefringence of the crystalline structure of enamel is colourful demonstrated.
In this way a different approach to visualize striae of Retzius as well as Hunter-Schreger bands is obtained.
Left side surface of enamel, right side thin bright area of dentin.
Incremental lines (striae) of Retzius are well shown as straight oblique zones. Hunter-Schreger lines appear as dark multiple horizontal bands (at the right side)
Top right a long dark fissure-like structure representing a crack.
Keywords/Mesh: oral cavity, mouth, tooth, enamel, Retzius, incremental lines, Hunter-Schreger, dentinoenamel junction, dentin, histology, POJA collection