Why does my dental turbine lose power when I start cutting?

A turbine that runs fine with no load but loses power the moment the bur touches a tooth is not getting enough air. Either air is leaking out somewhere or something is restricting it. The most common cause is a damaged hose, followed by a loose hose connection, low air pressure to the chair, or a compressor that is not keeping up. Here is how to check each one.

Is it one handpiece, one chair, or the whole clinic?

Start here, because it tells you where to look.

• One hose on one chair: check the hose and its connection (causes 1 and 2).
• Every hose on one chair: check the chair's air pressure (cause 3).
• More than one chair, or other equipment too: check the compressor (cause 4).

1. Is the hose damaged?

The most common cause, and it is usually right at the end of the hose, just before the coupling. The air pipe inside the hose has kinked or split. That reduces the airflow, so the turbine spins fine with no load but slows down under pressure. It often gets worse over time and may come and go.

Quick test: Run the handpiece and move the hose around. If the power changes as you bend or move it, the hose is the problem.

Fix: Replace the hose.

2. Is the hose connection loose?

The hose connection at the base of the dentist element can work itself loose over time. You will not usually notice it when the handpiece runs free. When you put pressure on the bur, the air pressure in the line rises, and that is when air starts escaping from the loose joint.

Fix: Check the connection at the base of the dentist element and tighten it.

3. Is the air pressure to the chair too low?

If every hose on the chair is affected, the chair itself may not be getting enough air. Most chairs have an air pressure gauge you can check yourself; your user manual will show you where it is. A dental chair should normally run at around 4.7 bar.

Quick test: Watch the gauge while running one of the air lines. If the pressure drops a lot as soon as air starts flowing, something is restricting the supply: a kink, a blockage or a valve that is not fully open. On some older chairs, such as the Sirona C8+, the main switch may not have been turned all the way on.

Before going further, check whether other equipment in the practice is affected too. If it is, the problem is probably the compressor, not the chair (see cause 4).

Fix: If it is only this chair and the main switch is fully on, this one usually needs a technician to track down.

4. Is the compressor keeping up?

If more than one chair or piece of equipment is losing power, check the compressor first. Look at the pressure gauge on the compressor itself. A dental compressor should never drop below 5 bar. If it is sitting lower than that, or drops below 5 bar when equipment is in use, the compressor is not keeping up and every chair will suffer.

Fix: A compressor that cannot hold pressure needs a technician. Note the reading on the gauge before you call, as it helps us work out the cause.

How do I stop this happening again?

Hoses fail early when they are kinked in storage or wiped with harsh disinfectants that attack the rubber. Let them hang straight, use the cleaning products your chair manufacturer approves, and glance at the compressor gauge once a week so a slow decline is caught before it stops a surgery.

Still losing power?

If you have checked the hose, the connection and both gauges and they all look normal, call Universal Dental Solutions on (02) 8313 0559. Depending on your chair, there are a few more things we can talk you through over the phone at no charge before anyone needs to come out.

Frequently asked questions

What air pressure should a dental chair run at?

Around 4.7 bar is typical. Check your chair's manual for the exact figure for your model.

What pressure should a dental compressor hold?

A dental compressor should not drop below 5 bar during normal use. If it does, it is not keeping up with demand.

Why does my turbine work on one chair but not another?

If the same handpiece works on one chair and loses power on another, the fault is in the second chair's hose, connection or air supply, not the handpiece.

Can a worn turbine cause loss of power under load?

Yes. Worn bearings or a damaged rotor can also cause power loss. If swapping to a different handpiece fixes the problem, the handpiece is the cause and should be sent for repair.