(PR02) Effect of Irrigant Extrusion From Simulated Immature Root Canals on the Stem Cells of Apical Papilla

Objective: To determine whether XP-Endo-finisher (XPF) used to activate irrigation affects the viability of SCAP by the extruded NaOCl. Materials and methods: Extracted maxillary incisors with single canals were selected. Crown and apical 3 mm were removed to obtain the standardized length of 15 mm. Root apices were enlarged to 1.30 mm to simulate an immature open apex. After sterilization, prepared specimens were randomly divided into four experimental groups: i)1.5% NaOCl, ii) 1.5% NaOCl with intermittent or iii) continuous activation using XPF, iv) 5% NaOCl, and two control groups: v) irrigation with PBS and vi) no irrigation (n=6/group). Teeth were inserted into sterile tubes filled with agar gel loaded with SCAP. After irrigation, teeth were removed and SCAP viability in agar gel was determined using Cell-Titer-Glo viability assay and visualized under confocal laser scanning microscope.

Results: The control groups showed similar cell viability (p>0.05). 1.5% NaOCl irrigation significantly reduced SCAP viability regardless of irrigant activation compared to control groups (p < 0.05). Activation using XPF did not affect the cytotoxicity of 1.5% NaOCl (p>0.05). The highest cytotoxicity was observed with 5% NaOCl (p < 0.05).

Conclusions: NaOCl significantly reduced cell viability regardless of the concentration. The use of XPF activation does not increase the cytotoxic effect of NaOCl on SCAP in simulated immature roots.