Practice Tips #88: How to Restore Flow to Your Ultrasonic Scaler

Even with proper protocols in place (i.e. the correct treatment and filtration), clogs can still occur in your water lines. This month, we’re going to focus on one of the most commonly clogged devices, the ultrasonic scaler (Cavitron™).

We went over the importance of ultrasonic scaler maintenance a few years ago, and even further back in Practice Tips #18 we covered waterline clogs: how to recognize if you have one and what to do about it. Using a self-contained water system gives you better control of water quality and helps you treat the lines to inhibit biofilm growth in accordance with ADA guidelines (see Practice Tips #55 and #56).

Biofilm build-up is still a very common cause of clogs in dental unit water lines. Ultrasonic scalers have very small water lines and generate a tremendous amount of heat, making them ideal breeding grounds for biofilm. We see and hear of more clogs in ultrasonic scalers than any other device.

As discussed back in PT #18, one of two behaviors will typically be exhibited if you have a clog:

  1. No water flow (as you might expect) or
  2. A normal flow that starts off fine and then trickles off to nothing.

The latter is the most common behavior of a clogged line. It’s rare for lines to get completely blocked. Typically, flow is restricted (but not completely blocked), so pressure builds up when the unit is not in use and you get good flow at first. The obstruction prevents good flow, so the water flow rapidly drops off to near nothing. Once you’ve determined you have a clog, how do you proceed?

First, determine if the clog is in the scaler tip or in the unit. To find out, remove the tip and run the unit. Do you get water out of the handle without a tip in place? Does the water flow for a long time uninterrupted? If so, the clog is in the tip. You can attempt to clean the water passage of the tip with a handpiece cleaning wire or similar small stiff wire. Blowing air backwards through the tip (you can use our etcher adapter or an air/water syringe) will free up anything in the lines. Be sure to wear safety glasses whenever attempting to blow out debris. An endodontic file or barbed broach can also be used to mechanically clean the tip.


This ultrasonic scaler tip has a water port underneath and is where a clog is possible. (#59-T91 is shown above)

If the clog is in the unit (i.e. no water comes out of the handle with no tip installed), you can still try blowing out the line. Again, work from the end backwards as debris usually works its way in from the opposite direction. Before applying air, turn the unit on and step on the foot control to open up the solenoid, so the air (and debris) has somewhere to go. Make sure to disconnect the water line from the back of the unit. An air flush of this nature can take some time, so let the air run for several minutes. If this doesn’t remove the obstruction, you may need to replace the solenoid (American Dental Accessories, Inc. carries several replacement solenoids for specific models of Cavitron™ brand scalers) or you will need to send it in for servicing. You can attempt to flush the unit with a water line cleaner too. Connecting the unit directly to a self-contained water system is the easiest method of accomplishing this, but you can also use a simple syringe to introduce a solution into the line, flushing the line as you would flush the socket of a freshly extracted tooth.

Removing the obstruction from an ultrasonic scaler is really the same as removing the obstruction from any other line. If you can access the entire line, using an object to free the line (like a wire) is usually a good option. If not, use high pressure air to blow the obstruction out. Solutions can help to break down the obstruction to more easily remove it.


This is a typical inline water filter used on ultrasonic scalers (see #49-57)

Of course, checking and changing your filters regularly, using self-contained water systems to treat the water, and cleaning & sterilizing your ultrasonic tips between patients will help tremendously in preventing clogs from forming in the first place.

Clogs can happen, but by following the steps above, you can clear your lines and be back in business in no time.



    Hello, Mohammed. Did you try finding the source of the clog? Is it in the handpiece or tubing? Did you do the suggested tips in the blog post above? Once you’ve tried those things. Please give us a call to help diagnose your scaler further.

  • Mohammed Idris Shehu

    My woodpecker got clog and no nearby location to service it what do I need to do now I have try all my best to repair it but it’s aren’t just working


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