Purpose: demonstrate crystalline phase transformations in the gutta-percha material and to determine at what points in the thermal cycle they take place.
N= 8 single-rooted human teeth
- Teeth were prepared for the warm gutta-percha packing procedure by cleaning and shaping the root canals with serial reaming and filing. teeth were then sectioned longitudinally.
- In a single half of each specimen, channels were bored through the dentin from the internal pulpal wall to the external surface of the root for thermocouple . The two halves of each specimen were then cemented back together.
- Endodontists were asked to fit a master GP cone, evaluate it radiographically and pack it while being monitored.
Most highlighted Results:
- There was variations in thermal patterns resulted from individual differences in timing and instrumentation. Certain clinically accepted patterns of activity produced consistent, representative temperature ranges to which the gutta-percha was subjected.
- The representative maximum regional temperature to which bulk gutta-percha is subjected in the body of the canal during the warm gutta-percha packing procedure is 80o C.
- Maximal temperature range to which gutta- percha is elevated in the apical region is 40o to 42o C.
- Thermal penetration of gutta-percha is limited during the packing procedure, with significant thermal effects rarely exhibited more than 4 to 6 mm into the material from the point of entry of the heat source, or more than 2 to 3 mm. from the point of deepest penetration.
Clinically relevant to any warm GP obturation technique.