Morphology of the root canal wall and arrangement of underlying dentinal tubules.

The morphology of the root canal wall and the arrangement of the dentinal tubules underlying it were investigated in this study. Fifty clinically sound single-rooted human teeth were cut for longitudinal and transverse sections. After dissolving the organic components and removing the smear layer, the specimens were prepared for scanning electron microscopy. In the upper root level, semiglobular calcospherites were present on the canal wall and a convergent arrangement of the dentinal tubules was found on the transverse sections. At the mid-root level, an irregular area of calcification comprising of compressed calcospherites began to appear on the proximal wall and increased towards the apex. The transverse sections showed the crowding and convoluted arrangement of the dentinal tubules near the canal wall, in the proximal area. A correlation was noticed between the irregular calcification on the wall and a convoluted tubular arrangement below the wall. These features were common in most of the specimens. This irregular secondary dentine does not appear to be pathological but physiological: associated with the normal ageing of the root.