Comparison of sonic and ultrasonic activation for removal of calcium hydroxidefrom root canals - A micro-CT study

Residual calcium hydroxide in the root canal can affect the quality of the root canal filling. The purpose of the present study was to use microtomography (micro-CT) for evaluating the efficacy of sonic and ultrasonic activation in removing calcium hydroxide. Thirty-two single-rooted mandibular premolars were prepared using a ProTaper next to X3 and were filled with a calcium hydroxide paste. The teeth were divided into two groups (n = 16) and an the initial scan was subsequently performed using micro-CT. Following a seven-day incubation under 100% humidity at 37° C, the calcium hydroxide was cleaned with an irrigation solution that had been activating using either a sonic (EDDY™, VDW) or an ultrasonic instrument (IrriSave, Acteon Satelec). After cleaning, a second with micro-CT scan was performed for determining the volume of residual calcium hydroxide. The data were reconstructed and analyzed using the NRecon and CTAn software. The ultrasonic group had a lower mean residual volume of calcium hydroxide than the sonic group; however, the difference was not statistically significant (p = 0.225). Sonic and ultrasonic techniques have the same ability to remove calcium hydroxide from the root canal.