In vivo findings associated with heat generation during thermomechanical compaction of gutta‐percha. Part I. Temperature levels at the external surface of the root

Temperature elevations of 10 degrees C above body temperature, of duration greater than 1 minute, may be sufficient to cause bone tissue injury. Temperature rises on the root surface in excess of 10 degrees C have been shown in studies in vitro of thermoplasticized gutta-percha root filling techniques. To determine whether results in vitro at room temperature could be extrapolated to conditions in vivo, temperature elevations were recorded at the mid-point on the root surface of the canine tooth in the ferret during thermomechanical compaction of gutta-percha. The time taken for the temperature to return to normal was also measured. There was no statistically significant difference between temperature elevations recorded in vitro and those measured in vivo. A linear extrapolation may therefore be made from results recorded at room temperature. Temperature elevations dissipated more rapidly in vivo than in vitro; this may be due to the cooling effect of the microvasculature of the periodontal membrane.