Dental Unit Q&amp;A: Water Lines, Foot Controls, Vacuum

A customer complained about the taste of the water. I use distilled water and BluTab tablets to clean the waterline. What am I doing wrong?

Our suggestion is to use treated tap water in your dental unit, as well as the BluTab tablets. Also, take a look at your bottle system's maintenance guide for suggested treatment too.

I want to incorporate electric handpieces with my dental unit. Between A-dec and Midmark, which one should I choose?

Reliability and performance wise, A-dec. A suggestion pertaining to the handpieces: get them installed with the purchase of your dental unit. It is more cost effective. If you go with another brand of handpiece, you will have to retrofit it to work.

My junction box is leaking air. Tightening the screw didn't help. What should I be fixing?

You need to figure out where the leak is by coating the assembly with soapy water and looking for air bubbles. You might have a hole the size of a pin in the line somewhere or there is an o-ring/gasket is worn and needs replacing.

My water bottle on my dental unit is filling up with water. Do I need a new water bottle system?

No. Replacing the bottle system should not be necessary and may not even be effective. Having the bottle fill like this would normally only happen if you have a connection to your municipal water supply. It could be a failed routing valve. Is water coming in from the top of the bottle? If so, you have water in your air line (i.e. cross-over). Check out issues #50 & #51 of Practice Tips for possible causes of this phenomenon.

I'm getting a loud noise coming from inside my A-dec delivery system & one handpiece is losing torque. What could be causing this?

First of all, 4-hole (ISO-B) tubing includes an exhaust line. The exhaust feeds into the delivery system, so some noise is normal. You can purchase an exhaust muffler to reduce this noise. If you have an unusually loud noise, you've likely got a rupture in your drive air line. Trace & inspect the handpiece tubing and look for tears. Coating the tubing with soapy water & running the handpiece will show where the leaks are by bubbling, making them easy to locate. There could, also, be a leak from the handpiece block. Lastly, A-dec has an oil collection jar mounted to the underside of most of their units. A 2" x 2" gauze is used in this jar as a filter. If the gauze is saturated, it could generate back pressure, causing noise or even lead to a hose becoming detached. Make sure the jar is empty, the gauze is clean, & all exhaust hoses are still attached to the jar. Read more about ISO in Practice Tip #36.

The rheostat I use needs to be stepped on multiple times for it to work. How should I fix it?

Foot controls or pedals aren't hard to fix if you know what you are doing, but there are a few things you should do before you replace any parts. Turn off your unit and step on the foot control to de-pressurize. Unscrew the four screws on the bottom to open it up. Hold it all together and flip it back over, gravity will hold all the pieces together. Like most repairs, a before photograph will help you put it back together once you find what's wrong with it. Before you order any replacement parts (i.e. rebuild kits), give it a once over and lube the o-rings and valve stem with some silicone lubricant (#03-40). Worn or dried out o-rings could be causing your foot control to act up. Make sure to clean it out with a cotton swab if you see any debris inside. If that doesn't fix your problem, then check out our repair kits to find the right replacement parts. Practice Tip #61 will help you take apart your foot control.

My foot control is brand new, but it is whistling and leaking air. Did I install it wrong?

Yes you did, but it is a quick fix. Switch the air in & air out tubing. This happens all of the time.

I'm looking at three "breakaway" style rear delivery units (DCI auto control unit, Belmont unit with assistant arm, & a Beaverstate unit with vacuum). What are the differences? Are they "self contained" systems?

Despite the units being three different brands, they all have equal quality. They aren't true "self contained" systems with their own compressor and vacuum, but they have the possibility of being outfitted with a self contained water system (not needing to connect to plumbing for water), as well as a portable compressor. It is more cost effective and will provide higher performance if you have a central vacuum and compressor.

Have just completed in-office waterline quality tests on my operatories and found the CFU levels to be quite high. How should I go about lowering these numbers?

You will need to shock your lines again. Extra treatment might be required and be even more effective. Follow up your treatment with another test. Depending on your new levels, try a few more shocks and test again. If your levels are still high, you could replace your lines. Even though it is time consuming, replacing the tubing isn't expensive or difficult., but replacing the lines might not be efficient. There could be build-up inside the various valves and other internal components inside the delivery unit.

Do all dental units come with anti-backflow valves?

After 1992, all units have anti-backflow valves built in to them.

The jar under my dental delivery unit that is used for collecting and filtering oil is leaking water when I run a slow-speed handpiece. I've done what I can to fix it, but nothing is working. What is going on?

Your problem is most likely cross-over. You might have water in your air line. We discuss this in depth in Practice Tip #50 & #51. If you have a swivel quick disconnect handpiece, change out the o-rings, just to be safe. You could have a ruptured diaphragm somewhere.

I am having an issue with the slow-speed handpiece connected to my delivery unit. The valve isn't shutting and I have to tilt it until the handpiece shuts off. What can I do to fix this?

Try turning off your unit and depress the foot control to exhaust the line pressure. Loosen the small hex set screws on the underside of the handpiece holder (this is what holds your handpieces in place) and slide the holder's valve forward, then back into the holder. There will be a "button" (valve stem) sticking out the front of the valve. If you do this correctly, it should just contact the little lever in the holder and will trigger when you hang up the handpiece. If that doesn't work, the valve could be bad.