Changes in dimensions and weight of human dentine after different drying procedures and during subsequent rehydration.

Shrinkage of dentine and the decrease in its weight after drying were measured. Three drying procedures were used, freeze-drying and drying in nitrogen at 60 and 100 degrees C. The dentine was subsequently rehydrated while measuring its dimensions. Rehydrated dentine was weighed. Dentine weight decreased by 10.2, 9.0 and 10.5% with the three different drying procedures. Shrinkage was about equal with all three methods. Linear dimensional changes were 1.7-2.0% in the plane perpendicular to the tubules and 1.4-1.7% in the direction of the tubules. During rehydration, freeze-dried dentine and dentine dried at 60 degrees C regained its original wet dimensions and weight. Dentine dried at 100 degrees C showed some permanent shrinkage and weight loss.