Effect of Conventional, Laser- and Sonic-Activated Irrigation on the Sealing Ability of Root Canals Obturated with a Bioceramic Sealer: An In Vitro Study

(1) Background: Irrigation activation techniques may improve the success of endodontic treatment by removing the smear layer and enhancing the sealing ability of bioceramic sealers. The aim of this work was to compare the efficacy of different irrigation activation protocols and assess their subsequent influence on the sealing ability of teeth obturated with a bioceramic sealer. (2) Methods: Fifty-three extracted human single-rooted teeth were mechanically prepared with HyFlex EDM rotary system. The samples were randomly assigned to three experimental groups based on the final irrigation activation protocol using PIPS, EndoActivator and Conventional Needle Irrigation and two control groups (positive and negative). Root canals were then obturated using a single-cone technique with a bioceramic sealer (CanalPro Calciseal). Apical microleakage was analyzed through nuclear medicine, incubating the specimens for 3 h in a sodium pertechnetate (99mTcNaO4) solution and quantifying radioisotope infiltration with a gamma well counter. (3) Results: The laser activation group demonstrated the lowest mean microleakage values (37.86 [35.77–42.82]), followed by the conventional irrigation group (50.96 [37.06–103.70]) and the EndoActivator group (52.34 [40.11–64.57]). (4) Conclusions: No statistically significant differences were found among the three experimental irrigation activation protocols. Laser-activated irrigation (PIPS) showed a numerically lower mean microleakage value, representing a trend toward minimal leakage.