[The reaction of the pulpal blood circulation to thermal stimuli]

The present paper characterizes the reactions of the systemcirculation and microcirculation of the pulpa to the effects of temperature changes from--30 degrees C to +55 degrees C. In the range between 25 degrees C and 50 degrees C an increase of the blood flow rate can be observed. By long-standing action of temperatures above 40 degrees C and below 25 degrees C a dilatation of the blood vessels and a decrease of the blood flow rate are caused, thus leading to aggregations, capillary stoppage, and finally to thrombosis of entire pulpa sections. In addition to the outline of the critical initial alterations of the microcirculation in the course of inflammation the clinical conclusions towards crown and cavity preparation by means of water spray cooling, concerning thermal sensibility tests, and cryo-surgical operations are discussed.