Sterilization of Handpieces: The Effect

The effects of heat on handpiece turbines is radical, primarily due to the effects on the rubber/neophrene components therein.

Prior to the mandate by Dental Associations all over North America to sterilize high-speed handpieces after each clinical use: they averaged about a 1000 clinical cycle, in longevity.

When Aids, Hep A+B and other high-risk factors came into frontal play, and sterilization of HP’s was strictly mandated, the average longevity fell to about 500 clinical sterilization cycles: or a 50% reduction in lifespan: a necessary cost to the clinics: to ensure hygiene.

That reduction of 50% is at the normal 132 to 135 degrees Celsius. When that temperature is higher than those temperatures, the longevity of the handpieces is reduced, in terms of the clinical cycles before the handpiece turbine is ruined: and from what we’ve been able to ascertain, that reduction-ratio in longevity is exponential, rather than geometric.

In other words: at 132C, and getting 500 cycles before rebuild, if ‘cooked’ at 140C, they can expect a reduction of at least 40%, down to 300 cycles.

But at 150C, they can be ruining their turbines almost immediately: and getting, l if they are lucky, perhaps 15-20 cycles. Obviously, it is to their best interests to keep the regulated temperatures of the sterilization units at proper settings.

There are many factors involved in this, some of which are:

1) Type of sterilization: ie: steam or chemi-clave (chemi-clave is harder on most handpieces than steam), and the flash-point of the sterilizer (some Statums flash up to 142-145C before settling back to 132-134C (this should be checked by the general-equipment technician at the clinic)

2)Type of handpiece involved: some will withstand the heat slightly better than others, but not enough to radically affect the results of temperature increases.

3)Type of lubricant involved:

a)Some lubricants (noteable, KaVo, MidWest , NSK: primarily those with a petroleum (mineral) or vegetable oil base, are certainly the most affected types. A good synthetic with a higher ‘flash’ point will withstand increased temperatures much better.

b) Lubricants that have inherent cleaning properties, which are used to properly maintain the handpiece (ie: sufficient lubricant is injected, it is properly purged through the handpiece and the internal handpiece cleanliness is checked by studying the cleanliness quality of the purged lubricant: if not, then should be re-lubricated and again fully purged until the expelled lube is CLEAN), then two things are to the advantage of the handpiece welfare:

1) it is clean inside around the bearings and chuck, when sterilized, hence, the detritus in the handpiece is flushed out, and is not being ‘cooked’ into the bearings/spindles/chucks: simply put, it is clean inside.

2) with a GOOD synthetic lubricant, which is designed with a high flash point, and which will withstand the rigors of sterilization better without loosing it’s lubricating (friction reducing) properties, higher than normal sterilization temperatures (WITHIN REASON: 4-6 degrees) can be reached without unduly injuring the rubber seal/O-rings, etc: of the handpiece. REGARDLESS: there is no need for higher-than-normal (132-134C) sterilization temps, and it is generally deleterious to all equipment.

Where does EZ lube OneStep Dental Handpiece Lubricant come in?

a) It has a very good inherent cleaning property: used properly for a couple weeks in clinical sterilization cycles, the interior cooked-in debris, left from using substandard lubricants: will begin to ‘wash’ off the interior parts of the handpiece. You may find handpieces coming in where the supply (air/water spray) lines have been clogged by the debris that is now being dislodged from the lines by EZ lube: that is a natural and desired effect. You KNOW the handpiece is being cleaned inside. After unclogging those lines, and explaining to the client what it happened, it is very doubtful that the Doctor will again see that problem relating to that specific handpiece. It should also convince him that EZ lube is indeed doing it’s job.

b) It has a very high flash-point (517F), and withstands the effects of the normal temperatures without any effect on the friction-reduction potential of the lubricant: simply put: it holds up properly in sterilization. Hence, when the handpiece is properly maintained (proper amounts are injected into the handpiece with the proper delivery method: Spray-cans for swivel hp’s, high-speed electric handpieces done properly), and properly purged to flush out the debris from the handpiece: there is NO need for additional lubrication AFTER sterilization.

That is NOT the case with many of the sub-quality handpiece lubricants, especially those which require a pre-cleaning solution to be injected into the handpiece, and also especially those with petro/veggie base. They tend to leave a film or crystallization build-up in the handpieces: both of which shorten the lifespan of the handpiece, and reduce it’s effectiveness (torque) while it does last.

You will find that once it is used for a few months to prove it self: you will recognize the benefits of continued use. It truly is the best lubricant available for the handpieces, and reducing repair administration time cost, repair and parts costs, and shipping costs: means it is good for your business’s bottom line as well.