Various methods of fixation were tried on dentine of 45 premolars from children. Two methods based on immediate or delayed use of liquid nitrogen, as well as a cryoprotector (10 per cent dimethylsulphoxid), gave the best results in transmission electron microscopy. Using these methods, the presence of an odontoblast process could be demonstrated in the inner, middle and peripheral human root dentine. The presence of unmyelinated nerve fibril in outer root dentine supports the hypothesis of direct neural stimulation in peripheral dentine.