The Effect of Apical Size Enlargement and Irrigant Activation on Elimination of Radicular Pulp Tissue: A Histological Study

Objective: This study aimed to determine the influence of different apical preparation sizes and irrigating solution activation on removal of pulp tissue remnants through histological assessment. Materials and Methods: A total of 50 vital, freshly extracted mandibular premolars were included and assigned into 5 groups: 4 experimental groups according to the preparation size and irrigation protocol and one negative control group: roup (1): apical enlargement of the samples up to file #30/.04 with conventional syringe irrigation (CSI), group (2) apical enlargement up to file #30/.04 with passive ultrasonic irrigation (PUI), group (3) apical enlargement up to file #40/.04 with CSI, group (4) apical enlargement up to file #40/.04 with PUI, and group (5): no mechanical preparation or irrigation was done. After histological examination, each sample was given a score representing the absence (score 0) or presence (score1) of pulp tissue remnants. Results: samples prepared to file #30/.04 with CSI (group 1) had significantly higher amount of pulp tissue remnants compared to all other experimental groups. There was no significant difference between groups 2, 3, and 4. Conclusion: Apical preparation with file #30/.04 is sufficient with PUI, whereas apical enlargement up to file #40/.04 is mandatory with CSI.