Effect of Different Chemo-Mechanical Shaping Protocols on the Intratubular Penetration of a Bioceramic Sealer

<b>Background</b>: This study aimed to evaluate the effect of two shaping systems combined with different irrigant activation methods on the tridimensional distribution of a bioceramic root canal sealer. <b>Methods</b>: Sixty single, round, straight root canals from extracted human teeth were randomized into six groups (<i>n</i> = 10): A1-A3 shaped with RACE NiTi rotary files; B1-B3 shaped with an adaptive XP-Endo Shaper. NaOCl and EDTA irrigation was performed using passive ultrasonic irrigation (PUI, group 1), conventional endodontic needle irrigation (CENI, group 2), or XP-Endo Finisher mechanical activation (group 3). Canals were obturated using the single-cone cold gutta-percha technique with BioRoot RCS bioceramic sealer. Confocal laser scanning microscopy was used to assess sealer penetration (mean and maximum depths and percentage), and sealer integrity on canal walls at coronal, middle, and apical levels. <b>Results</b>: The XP-Endo Shaper combined with the XP-Endo Finisher showed the highest mean sealer penetration depth, while RACE with PUI had the lowest (B3 vs. B2 <i>p</i> = 0.02; vs. A1 <i>p</i> = 0.05). No significant differences were observed in the maximum penetration depth and percentage of penetration across groups. Sealer integrity was significantly lower in the RACE + XP-Endo Finisher group (<i>p</i> < 0.01). Coronal regions consistently showed higher mean and maximum sealer penetration and percentage of penetration compared to apical thirds, with no significant differences in sealer integrity within root regions. <b>Conclusions</b>: The combination of the XP-Endo Shaper and XP-Endo Finisher showed a tendency towards superior sealer tridimensional distribution, particularly in the middle and apical thirds. This in vitro study suggests that adaptive shaping instruments combined with mechanical activation enhance sealer distribution, potentially improving treatment success.