A Micro-Computed Tomography Analysis of Void Formation in Apical Plugs Created with Calcium Silicate-Based Materials Using Various Application Techniques in 3D-Printed Simulated Immature Teeth

<b>Background/Objectives</b>: The management of immature teeth with wide apical foramina presents significant challenges in endodontic treatment due to difficulties in achieving a hermetic seal. The aim of this study was to evaluate void formation in apical plugs created using three calcium silicate-based materials-Biodentine, NuSmile NeoPUTTY, and Well-Root PT-applied with the help of manual, ultrasonic, or rotary file condensation (XP-endo Shaper) in 3D-printed immature teeth. <b>Methods</b>: Micro-computed tomography analysis was used to assess the internal, external, and total void percentage of material volume. The statistical analysis was performed using two-way ANOVA and the post hoc Bonferroni test. Statistical significance was set at <i>p</i> < 0.05. <b>Results</b>: The materials and techniques used individually do not significantly influence the formation of internal voids, but their combination does (F(4, 99) = 2.717, <i>p</i> = 0.034). Both factors and their interaction are significant for external voids (F(4, 99) = 4.169, <i>p</i> = 0.004), and all have a notable effect on total void percentages (F(4, 99) = 3.456, <i>p</i> = 0.012). No significant differences were observed in internal voids across the groups (<i>p</i> > 0.05), ranging from 0.635% to 1.078%. External voids varied significantly, with Well-Root PT and ultrasonic condensation showing the highest values with a significant difference (<i>p</i> < 0.05), while NeoPUTTY and Biodentine with XP-endo Shaper exhibited the lowest. Total voids remained below 4%, with no significant differences among manual condensation groups. Neither material type nor application technique consistently influenced void formation, except for Well-Root PT with ultrasonic condensation. <b>Conclusions</b>: These findings suggest that modern bioceramic materials and application techniques produce comparable, low-void apical plugs, with XP-endo Shaper showing promise for minimizing external voids. The interaction between material and application technique plays a crucial role during the creation of apical plugs.