Two dental practices can use the same model handpiece and get very different service lives from their turbines.
That doesn't necessarily mean one office uses better maintenance procedures or superior turbines than the other.
How often a handpiece is used, how many instruments share the workload, the drive-air pressure, the type of cutting being done, and whether an instrument continues to be used after its performance begins to change can all affect how long its components last.
This is the first of a three-part series examining the primary causes we observe that accelerate premature handpiece failure.
In this post, we'll concentrate on how the handpiece is being used. In the next two, we'll look at maintenance and processing practices, followed by mechanical problems and recurring failure patterns.
1. Calendar Age Doesn't Tell The Whole Story
One of the most common questions we hear is: “How long should a turbine last?”
It is a reasonable question, but there isn't a useful answer based on months alone.
A turbine that lasts six months in a very busy operatory may have accumulated substantially more operating time and sterilization cycles than a turbine that lasts a year in another office.
Consider two operatories using the same handpiece.
One has several high-speeds available and rotates them throughout the day. Another relies heavily on one or two instruments and cycles each of them repeatedly.
Six months of use does not represent the same amount of work in those two situations.
That doesn't mean you should ignore turbine life. Quite the opposite.
If your turbines have historically lasted a certain amount of time and suddenly begin failing much sooner under approximately the same conditions, that change is worth investigating.
Your own repair history is often a much better benchmark than somebody else's claim about how many months a turbine “should” last.
2. How Many Handpieces Are Sharing The Work?
The number of handpieces available in an operatory directly affects how much work each one has to do.
An office with three or four high-speeds available can distribute operating time and sterilization cycles among them. An office relying on one or two will naturally accumulate those cycles much faster on each instrument.
This isn't an argument that every office needs a specific number of handpieces.
It is simply one variable to consider when evaluating service life.
If your practice is busy, your handpieces are used more heavily, and each instrument is sterilized several times a day, a shorter calendar life does not necessarily indicate an abnormal failure rate.
The better question is:
How much work did the handpiece actually perform during that time?
3. Higher Air Pressure Can Increase Performance - And Wear
This is one area where the tradeoff is fairly straightforward.
Before Dentalight, I spent years in the garment industry. In our factories, we sometimes wanted a sewing machine to run faster than it was originally designed to.
One way to do that was to install a larger pulley.
It increased production.
It also increased wear, maintenance, and the likelihood of mechanical problems.
We knew that going in. Sometimes the additional production made the tradeoff worthwhile.
Increasing drive-air pressure on a dental handpiece involves a similar principle.
More pressure can make a turbine feel more powerful or responsive, and in a busy practice that additional performance may seem worthwhile.
But the turbine is also being asked to operate under more demanding conditions.
Higher speeds and loads increase stress on components already operating at extremely high RPM.
That does not mean every turbine failure is caused by excessive air pressure. It means pressure is one variable to check when turbine life seems unusually short.
And the relevant pressure is the pressure being delivered to the handpiece under operating conditions - not simply what a regulator happens to display somewhere upstream.
4. How The Handpiece Is Asked to Cut Matters
Not every procedure places the same load on a turbine.
Heavy cutting, lateral pressure, and dull burs can all increase the forces being transmitted through the bur, chuck, and bearings.
A dull bur is a good example.
If the bur isn't cutting efficiently, the natural response is often to apply more pressure.
That additional pressure does not disappear. It is transferred back through the rotating assembly.
The same principle applies when a small-head handpiece is repeatedly asked to perform demanding cutting that would be easier for a larger or more powerful instrument.
This does not mean a dentist should be thinking about turbine bearings during every procedure.
It does mean that how a handpiece is used is part of its maintenance history, even though it never appears on a repair invoice.
5. Small Problems Become Larger When Not Addressed Promptly
A handpiece does not always fail all at once.
More often, subtle changes appear first.
The sound may change. Cutting performance may decline. The bur may not feel quite as stable. An attachment may begin running warmer than usual.
The original problem may still be relatively minor.
Continuing to operate the instrument can increase vibration, friction, heat, or load on nearby components, turning a small repair into a larger one.
That was the focus of our previous post, [Is It Time to Service Your Dental Handpieces and Attachments?], where we looked at the changes that can signal developing problems before complete failure occurs.
Recognizing those changes matters because premature failure isn't always caused by the first component to wear.
Sometimes it is caused by continuing to use the handpiece after that component has already indicated that something is wrong.
Think in Patient Cycles, Not Time in Service
No single number tells you how long every turbine should last.
A busy practice with fewer handpieces in rotation, multiple daily sterilization cycles, demanding procedures, and higher drive-air pressure is placing considerably more work on each turbine than an office operating under different conditions.
That doesn't mean you simply have to accept premature failure.
It means you need to look at the conditions surrounding the failure.
If service life suddenly changes in your own office, ask what else changed.
That question often tells us considerably more than the number of months the turbine has been in service.
Next in this series: We'll look at what happens to the handpiece between patients - lubrication, cleaning and sterilization, air quality, and the maintenance routines that can either protect a handpiece or shorten its life.
Join the conversation. Do you have a question about handpiece maintenance you would like addressed in this series? Ask Neal.