Purpose: to answer the question regarding temperature changes occurring along the post and the root surface with the use of ultrasonic instrumentation for post removal.
n: 10 max CI and LI
•Canals were prepared using Profile rotary instrument in a crown down tech and obturated with GP and Roth’s 801 sealer.
•#5 Parapost drill was used to prepare the post space; post was cemented using zinc phosphate cement.
•Ultrasonic handpiece with a CPR 1-C (post removal tip) positioned on the top of the post in an axial direction with a static 500 g force for 1 min at maximum amplitude. No water coolant was used.
•Type K chromel/alumel thermocouples was attached at the post and 2 mm apical to CEJ, the other end was connected to the computer.
• The temperature was recorded on the computer at 15 s intervals.
•Time of ultrasonic application (15, 30, 45 and 60) at 2 location (post and root surface) were measured.
Most highlighted Results:
•Table 1 shows the mean temperature changes at each location and time period.
•There was a significantly greater temperature increase at the post surface than at the root surface
•There was a significant temperature increase at both the post and root surface as the length of time of ultrasonic vibration increased
Dentin is a poor thermal conductor and a small difference in dentin thickness may have a large effect in heat conduction. Teeth with thin roots and large posts could be more susceptible to the heat generation from ultrasonic application during post removal.