Temperature rise of the post and on the root surface during ultrasonic post removal

To determine the temperature rise on the root surface caused by ultrasonic post removal using different devices and techniques in a laboratory setting.

Two ultrasonic devices, one piezoelectrical (Pi) and one magnetostrictive (Ma), were investigated. A serrated titanium post was placed into the distal root canal of a human mandibular first molar. Four coolant parameters were utilized: no air, no water, no evacuation (NN), air only with high-speed evacuation (A), 15 mL min(-1) water coolant with high-speed evacuation (W15) and 30 mL min(-1) water coolant with high-speed evacuation (W30). Five simulated post removals were measured at two locations, the post (P) and the root (R), for each coolant parameter. Temperature rise was measured at 30, 60, 90 and 120 s intervals using calibrated infrared thermography (n = 80). Temperatures were recorded at 45 ms intervals. Data were analysed using repeated measures anova with the Scheffe post hoc test (P < or = 0.05).

The overall mean pooled effect showed that temperature rise for P = 20.1 +/- 27.9 degrees C and R = 10.9 +/- 7.9 degrees C were significantly different. Significant differences in temperature rise were: Pi > Ma, P > R, NN > A = W15 = W30 however, A > W30.

There were significant differences in temperature rise as a function of ultrasonic device, location on the tooth and cooling method utilized for post removal.