Effect of Agitation of Ethylenediaminetetraacetic Acid with Sonic and Photon-Initiated Photoacoustic Streaming Tecniques on Dentin Microhardness

Objective: The aim of this study was to evaluate and compare the effect of the ethylenediaminetetraacetic acid (EDTA) agitation with a sonic system and the photon-initiated photoacoustic streaming (PIPS) technique on the microhardness of the root canal dentine. Methods: A total of 24 extracted single-rooted human mandibular incisor teeth were collected. The root canals were instrumented according to the manufacturer's instructions using the reciprocating single-file system Reciproc. The teeth were decoronated, and the roots were longitudinally split into two halves. Following initial microhardness measurements of root canal dentine, the halves were connected, and the samples were divided into four groups, according the final irrigation protocol (Group 1, only distilled water; Group 2, EDTA; Group 3, EDTA+sonic agitation, Group 4: EDTA+PIPS agitation). Final microhardness values were calculated after the irrigation procedures. The Shapiro-Wilk test was used to evaluate the normal, or abnormal distribution of the values. For multi-comparison of the groups, one-way analysis of variance and post-hoc Tukey tests were used. Results: The EDTA significantly reduced microhardness compared to the distilled water group (p<0.001), while the results of the sonic and PIPS activation groups were statistically similar to the EDTA alone group (p=0.053 and 0.266, respectively). No significant difference was found between the agitation groups (p=0.853). Conclusion: The results of the present study revealed that neither sonic nor PIPS agitation resulted in further microhardness reduction.