Why do we actually clean and shape canals? If the goal of root canal therapy is simply to remove the infected nerve, why bother with rotaries or files at all? The answer is that when the pulp is infected, the surrounding dentin is also infected. Cleaning and shaping the canal into a cone shape isn’t just for convenience—it’s primarily to allow irrigants, especially sodium hypochlorite or EDTA, to reach the very bottom of the root. That’s why root canal therapy is called chemo-mechanical debridement.

Think of it like a dishwasher: if dishes are crammed in without space between them, the detergent and water can’t flow freely, and the dishes won’t get clean. The same principle applies in root canals—without proper shaping, irrigants can’t circulate effectively.

A common question I hear is: How long should I irrigate? But I believe the better question is: What do you do with your irrigant? Think of it like showering. For real cleanliness, you also scrub with your fingers. If you’re just standing on the shower stand, is that really cleaning? Similarly, effective root canal irrigation requires active use of irrigants—not just passive rinsing.

Sonic irrigation devices—like endoactivators—have limited efficacy. They work by creating cavitation (bubbles that burst), similar to the fizz in a glass of champagne. They look impressive, but do they really clean deeply? And are they worth the $1,000 price tag plus single-use tips? Personally, I don’t think so.

Ultrasonic irrigation, on the other hand, works by acoustic streaming. In plain terms, the vibrating tip scrapes canal walls, flushing bacteria from dentinal tubules and even cleaning lateral canals. Clinically, this not only improves disinfection but also makes your radiographs look cleaner and more impressive.

Inadequate irrigation can cause debris to pack at the canal’s apex, blocking your master cone from reaching working length. This can mimic ledges or broken files on X-rays and lead to unnecessary stress, wasted chair time, and reduced efficiency. My solution: after each rotary file size increase, I irrigate thoroughly and activate with ultrasonics. This prevents debris accumulation and keeps canals open.

From my experience, this approach also reduces the need to constantly recapitulate with hand files. Not only does ultrasonic cleaning save time, but it also avoids pushing infected debris apically—something that can compromise success rates.

Laser irrigation and GentleWave certainly look impressive and may even help “wow” patients or potential associates. But with price tags of $60,000 or more, plus increased treatment time, I struggle to justify the investment.

Ultrasonics remain my preferred method for efficient and thorough irrigation, and in later articles, I’ll share additional benefits of ultrasonic tips beyond irrigation.