Effectiveness of different irrigant activation techniques in removing smear layer: a scanning electron microscope study

Background: This study evaluated the effectiveness of Laser-Activated Irrigation (LAI), XP-Endo Finisher, and Endo Activator in removing the smear layer from root canal walls by assessing dentinal tubule opening in the coronal, middle, and apical thirds using scanning electron microscopy. Materials and Methods: Thirty single-rooted human anterior teeth were decoronated to a standardized length and prepared using the WaveOne Gold primary rotary system. The samples were randomly divided into three experimental groups (n=10): LAI, XP-Endo Finisher, and Endo Activator, along with a control group irrigated using a conventional syringe technique. The roots were split longitudinally and examined under SEM at 1000x magnification. Images were obtained from the coronal, middle, and apical thirds. Data were analyzed using the Kruskal–Wallis test, with statistical significance set at p<0.05. Results: No statistically significant differences were observed among the three experimental groups in any root third. However, all experimental groups showed significantly better smear layer removal compared with the control group. LAI demonstrated minimal smear layer and greater dentinal tubule openness in the coronal and middle thirds, although remnants persisted apically. The XP-Endo Finisher showed superior performance in the apical third, producing a thinner smear layer. The Endo Activator was most effective in the middle third but left substantial smear layer coverage apically. Complete smear layer removal in the apical third was not achieved by any method. Conclusions: XP-Endo Finisher was most effective apically; Endo Activator in the middle third; and LAI coronally. Utilizing advanced and varied techniques improves smear removal over conventional irrigation.