Interstitial fluid pressure in the pulp of the rat incisor.

This was measured in inactin-anaesthetized rats, using a cotton-wick technique. Access to the pulp was through an opening produced by repeated shortening of the incisor under anaesthesia. The pressure was subatmospheric and behaved as predicted by Starling's hypothesis. In teeth which had not been opened to the atmosphere, the pressure measured through a hole drilled during the experiment was approx. 300 Pa higher than in the repeatedly shortened teeth, but was still lower than the pressures recorded in teeth of limited eruption.