An ex vivo analysis of apical irrigant pressure developed by different irrigation needle types at various irrigant flow rates

Aim To analyze apical irrigant pressure developed by four needles, each at different flow rates, using an ex vivo model for endodontic irrigation. Methodology A human maxillary incisor root canal was shaped to the working length (WL) utilising rotary files up to size 40, 0.06 taper, patency size 10. The apical foramen of the root canal was sealed in closed system connected to digital manometer (PM- 9100HA, Omega Engineering, USA). Two notched open-end irrigation needles (Needle 1: Endo-EZE ; Ultradent Products, USA, and Needle 2: Appli-Vac ; Vista Dental, USA), one single side-vented (Needle 3: Appli-Vac, Vista Dental, USA) and one double sidevented (Needle 4: Calasept, Nordiska Dental, Sweden), all 27G, were used. Each needle was mounted 1 mm short of WL and constant flow rates of 0.05, 0.10, 0.15 and 0.20 mL s 1 of irrigant (3% sodium-hypochlorite) were delivered by Precision Syringe Pump (Aladdin, World Precision Instruments, USA). Apical irrigant pressure was measured (N = 20) for each flow rate. Two-way ANOVA without repetition analysis was used to determine statistical difference between needles types and the rise of irrigant flow rate. Results The highest value of apical irrigant pressure was developed by Needle 2 at 0.20 mL s 1 (68 2.66 mmHg), while the lowest by Needle 4 at 0.05 mL s 1 (2.25 0.55 mmHg). Results showed a significant difference between the notched open-end (Needle 1 and 2) and side-vented irrigation needle (Needle 3 and 4) type groups (F = 6.53, P < 0.05). Differences in needle type were not significant. The increase of irrigant flow rate resulted in a significant increase of apical pressure for all irrigation needles. Conclusions Apical irrigant pressure was influenced by both needle type and irrigant flow rate. Increase of irrigant flow rate increased apical pressure while the application of open-end needles was associated with increased apical pressure compared to side-vented.