The odontoblast process and its branches in human teeth observed by scanning electron microscopy.

Healthy teeth were fixed, resin-impregnated and freeze-fractured. Specimens were critical point-dried and examined by scanning electron microscopy. Odontoblast processes were observed in the inner-, middle- and peripheral dentine. The processes in the inner-third dentine closely approximated tubule wall and could be found in most of the tubules. Some tubules contained a thin fibre besides the odontoblast process. In the middle third of dentine, the processes became thinner, their appearance was cable-like with lateral branches and a wide periodontoblast space could be seen. Processes were seen only in a few tubules of outer-third dentine in both young and aged subjects. They divided into longitudinal and lateral branches and seemed to be connected with one another.