Passive Ultrasonic Irrigation versus Syringe Irrigation for Dental Debris Removal

Irrigation has a key role in successful root canal treatment. Objectives: To test the effectiveness of dental debris removal in root canals by comparing a Passive Ultrasonic Irrigation (PUI) with a Syringe Irrigation (SI) approach. Methods: Thirty straight single rooted extracted teeth were divided into two comparable groups. Canals were shaped with K-files (sizes 20-40) and cleaned with 3% sodium hypochlorite (NaOCl) using SI each time the file was changed. A new size 45 K-file was then used to create the apical box and smooth the more coronal walls. For the SI group, the canal was finally irrigated with 10ml of NaOCl from a syringe; for the PUI group, the canal was finally irrigated with NaOCl and PUI for 20 seconds three times. The amount of remaining dental debris in each part of each root canal was evaluated using a 4-grade scoring index under 40x magnification (0=canal empty; 1=less than half canal filled with debris; 2=more than half canal filled with debris; 3=complete canal filled with dental debris). Results: The overall mean debris scores for SI and PUI were 1.4 (±0.36) and 0.8 (±0.44) respectively (p=0.0006). There were no significant differences between the SI and PUI groups when comparing the debris scores of the most coronal parts (P>0.05). However, the PUI canals were significantly cleaner than the SI canals in the more apical parts. Within the SI group, the root canals were significantly cleaner in the more coronal parts compared with the apical parts, but vice versa for the PUI group. Conclusion: PUI appears to be more effective at cleaning canals (especially in the apical area) compared with the standard SI technique.