Aim: This study compared apple cider as a single irrigant or in combination with 17% EDTA to 2.5% sodium hypochlorite (NaOCl) followed by 17% EDTA for the removal of smear layer from the middle and apical thirds in single-rooted teeth using passive ultrasonic activation.
Materials and Methods: Forty human-extracted mandibular premolars were prepared and randomized into four groups (n = 10) according to the irrigation protocol. Group I: Apple cider, Group II: Apple cider followed by 17% EDTA, Group III: 2.5% NaOCl followed by 17% EDTA and Group IV: control (Saline). Following chemo-mechanical preparation, the roots were cleaved longitudinally into two equal halves and analysed by Environmental Scanning Electron microscope (ESEM) at 1000x to evaluate the presence of a smear layer.
Results: There was no statistically significant difference between Groups I, II, and III in the middle third of the smear layer score. All three groups results were significantly lower than those of group IV. In the apical third, there was no significant difference in the scores of groups I, II, and III. Compared to group IV, groups I and II had lower scores. Group III and Group IV did not differ significantly from one another. Groups I (p=0.247), II (p=0.218), and IV (p=0.971) did not significantly vary in the middle and apical thirds scores from one another. Between group III's middle and apical thirds, there was a significant difference (p<0.001).
Conclusion: Apple cider used alone or followed by EDTA can remove smear layer comparable with NaOCl followed by EDTA.