Evaluation of Sealing Performance and Canal Anatomy Dependency of Rotary Condensation Instruments for Sealer-Only Root Canal Obturation Using a Bioactive Glass-Based Sealer

This study compared filling characteristics and apical dye leakage during sealer-only obturation with a bioactive glass-based sealer using three rotary instruments. Straight and 30° curved simulated acrylic canals (apical diameter, 0.25 mm; taper, 0.07) were evaluated using an NT condenser, JIZAI, or a stainless steel (SS) prototype condenser (n = 15 per group per canal model). Sealer condensation was performed at 500 rpm with four up-and-down strokes. Unfilled areas were measured 3, 6, and 9 mm coronal to the working-length endpoint, which was set 2 mm short of the apical end of each model (equivalent to 5, 8, and 11 mm from the apical end). Apical dye penetration was assessed after 48 h in 2% methylene blue. Kruskal–Wallis and Steel–Dwass tests were used. In straight canals, the SS prototype showed the smallest apical unfilled area, whereas JIZAI and the SS prototype showed less dye penetration than NT. In curved canals, JIZAI showed smaller apical and middle unfilled areas and less dye penetration than the other instruments. Filling characteristics and dye penetration differed by instrument and canal geometry; three-dimensional evaluation is needed to establish overall sealing performance.