During endodontic treatment, we aim to remove all pulpal tissue, micro-organisms, and by-products from within the root canal system. We know that the root canal system is not only made up of the central canal but may have isthmuses, fins, webs, anastomoses & other irregularities. These variations in the canal shape are impossible to cleanse mechanically. We must rely on our irrigant to reach places our files cannot reach.
Opening the canals to a large enough size for the irrigant to reach the apex is a critical step. I also like to use what I call “ultrasonic stirring.” I use an ultrasonic instrument to “stir” or “vibrate” the irrigant as it sits in the canal. Below is a little video clip showing how I do this.
A recent randomized, single-blind study published in the Journal of Endodontics supports this practice as a way achieves more effective canal sterilization. Carver, Nusstein, Reader & Beck showed that canals cleaned and irrigated typically, followed by one-minute ultrasonic irrigation with an ultrasonic needle in a MiniEndo unit, resulted in a statistically significant (p = .0006) reduction in CFU count and positive cultures (p = .0047).
There are many ways to perform ultrasonic irrigation. I simply irrigate the canals using a disposable syringe and 5.25% NaOCl. Then I use a small stirring tip attached to my ultrasonic handpiece. I am sure there are other products on the market, but I like to use the instruments that I already have.