Comparative Evaluation of the Effect of Different Irrigation Regimens With and Without Ultrasonic Activation on Root Dentin Microhardness: An In Vitro Study.

Background The structural properties of dentin, including its microhardness, can be affected by exposure to endodontic irrigating solutions and ultrasonic activation. Aim The current study aimed to assess the effect of three different irrigation regimens, with and without ultrasonic activation, on the microhardness of the dentin. Methodology The research was conducted on 120 mandibular premolars randomly divided into four groups (n=30) based on the irrigation regimen, with each group further divided into two subgroups (n=15). Subgroups 'a" were subjected to respective irrigation regimens without ultrasonic activation. Subgroups 'b' were subjected to ultrasonic activation. The Vickers microhardness test was conducted on the samples, and the data underwent statistical analysis using the independent sample t-test, ANOVA, and the Tukey test. Results The observations of the study unveiled that the microhardness of the root dentin was decreased by all the irrigation regimens. Microhardness values of dentin showed higher reduction with ultrasonic activation than without ultrasonic for all groups. Conclusions The dentin microhardness was significantly reduced when 3% and 5% sodium hypochlorite were used with 17% ethylenediaminetetraacetic acid (EDTA) as irrigation solutions. Ultrasonic activation of the irrigants had an adverse effect on the microhardness of dentin.