Irrigation flow rate of 4 mL/min ideal for clearance of dye beyond needle tip in vivo root canal model

Results of the study are:

• Positive-pressure irrigation revealed a flow rate–dependent increase in apical pressure (P < .05).
• The apical pressure at high irrigation flow rates was several times higher than at low flow rates. Needle designs with safety features yielded statistically significant lower apical pressures than needles without safety features (P < .05).
• There was no further increase in dye clearance from the end of the needle tip in a plastic root canal model at flow rates higher than 4 mL/min.

Thus, if apical clearance of dye beyond the needle tip is a measure of irrigation effectiveness, then maximum effectiveness with safe apical pressures can be gained at specific flow rates using specific needle tip designs. The use of an irrigation flow rate of 4 mL/min was able to achieve maximum effectiveness in this study.

Reference:

Apical Pressure and Extent of Irrigant Flow beyond the Needle Tip during Positive-pressure Irrigation in an In Vitro Root Canal Model by Ellen Park et al. published in the Journal of Endodontics.

https://doi.org/10.1016/j.joen.2012.12.004