Assessing Conventional and Ultrasonic Irrigation for Debris and Smear Layer Removal in Primary Teeth: An In Vitro Scanning Electron Microscopy Study

This in vitro study compared the efficacy of conventional irrigation with a lateral vent needle using 2.5% sodium hypochlorite (NaOCl) versus ultrasonic irrigation with 2.5% NaOCl in removing debris and smear layer from primary molars. Twenty-eight primary molars were randomly assigned to two groups (n=14 each). After standardized root canal preparation, Group I underwent conventional irrigation, and Group II received ultrasonic irrigation. Debris and smear layer were evaluated using a Scanning Electron Microscope (SEM) at 200× and 1000× magnifications, respectively, across coronal, middle, and apical thirds, with scores ranging from 1 (clean) to 5 (dirty). Statistical analysis using ANOVA and Mann-Whitney U tests revealed that ultrasonic irrigation significantly outperformed conventional irrigation in debris and smear layer removal across all root canal thirds (p < 0.001). The apical third showed the highest debris and smear layer scores in both groups, but ultrasonic irrigation consistently achieved lower scores. These findings suggest that ultrasonic irrigation with 2.5% NaOCl is more effective for enhancing root canal cleanliness in primary teeth, potentially improving pulpectomy outcomes. Further clinical studies are needed to validate these results.