Monday, November 26, 2007

Ultrasonic Irrigation

During endodontic treatment, our goal is to remove all pulpal tissue and micro-organisms, by-products from within the root canal system. We know that the root canal system is not only made up of the main 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 the places that our files cannot reach. Opening the canals to a large enough size for the irrigant to reach the apex is an important 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 achieve more effective canal sterilization. Carver, Nusstein, Reader & Beck showed that canals cleaned and irrigated normally, followed by a one minute ultrasonic irrigation with an ultrasonic needle in a MiniEndo unit resulted in statistically significant (p = .0006) reduction in CFU count and positive cultures (p = .0047). Logistic regression showed that ultrasonic irrigation was seven times more likely to yield a negative culture. Source: Carver, K., Nusstein, J., Reader, A., Beck, M. In Vivo Antibacterial Eficacy of Ultrasound after Hand and Rotary Instrumentation in Human Mandibular Molars. Journal of Endodontics 2007;33:9:1038-1043.

There are many ways to perform ultrasonic irrigation. I simply irrigate the canals normally using a disposable syringe and 5.25% NaOCl. Then I use a small stirring tip attached to my ultrasonic handpiece. I am certain there are other products on the market, but I like to use the instruments that I already have.