…  and how to make sure they last.

Sound a little existential?   Well yes, it is.   

But it is at least somewhat true.  The dental handpiece is one of the most important tools to the modern dentist, along with newer developments such as digital imaging, CAD/CAM Milling units, etc. But without the handpiece, none of these other tools are of much use.  So arguably the handpiece is the most important tool in the practitioner’s hands – but in some aspects the bane of his existence as well. 

First - - from the patients prospective – the first thing whenever you mention that you are dentist, assistant or hygienist, or even a dental manufacturer, people cringe, and say they "hate" the noise of the drill.   Yes, when I mention to friends and acquaintances that my company manufactures dental drills, the first response is a squinched up face, and the words “I hate that noise!"  So I could only imagine what each practitioner hears every time they say they work in the dental field.   But then in addition, there are also the many other aspects that make the dental practitioner wince about their handpieces.  Among which, how much they cost to purchase, the cost of repair, availability of a handpiece out of the autoclave for their next case, are your assistants maintaining them correctly, using the correct lubricant, or even lubricating at all, do they need to be repaired, who to send them to?  Do we want to send them to the manufacturer and take a month to get them back, or can we trust that local guy, who says he’s putting in quality parts, but who knows what he's putting in there,  but he gets the job done quickly?    Enough to drive you mad, amongst the hundreds of other things you have to worry about while running a dental practice. 

Hopefully we can help you out to make the dental handpiece not another part in your existential crisis, but simply a tool in your arsenal, that if cared for a little and maintained properly, can run worry free for as long as possible. 

 

There is no such thing as over lubrication – though there is such a thing as under purging.   So – what in the world does that mean?   

You can put a gallon of lubricant into a handpiece (if you had the time or inclination) as long as you run the handpiece and purge out a gallon of lubricant.  You see the process of lubrication is not only what you think it’s for (most common thought here is that the handpiece needs oil to prevent friction to keep it running smooth and cool) and yes that’s part of the story, but not nearly half of it.   So we will start at the beginning to get you a little more educated on what a dental handpiece is made up of, and what it does. After your graduation from handpiece school, you will see the light. 

The dental handpiece – One of the fastest moving pieces of machinery on planet earth!
High speed handpieces can run at speeds up to 450,000 RPMS (RPM= Rotations per minute) With the average high speed running at about 400,000 rpms.  Wait- - 400,000 rotations per minute, do the math there, and you’ll come up with an approximate 6,666 rotations per second.   That’s right – your average high speed handpiece spins at over 6,000 times every second.   Count it,   1… there’s 6000, 2, there’s another.  It’s hard to believe something can actually move that fast, but it’s true - About 6,000 rotations every second.  So you’d have to imagine to spin that ridiculously fast it has to be an almost perfect machine – and it is. Most modern dental handpieces are works of wonder, precisely crafted, finely tuned ultra- modern machines at their finest.  Crafted with the finest tolerances available by the most sophisticated digital and laser systems available today. 

 

A brief description of what actually makes a handpiece. 

A high speed handpiece is primarily made of 2 basic parts. The turbine and everything else. In comparison, the turbine would be the engine, transmission and drive train of a car, and the shell would be the frame, doors, hood, etc.  At the back of the shell is a mechanism to connect to a dental tubing, and a few internal lines that allow air and water to pass from your tubing to the turbine Some more modern handpieces have fancy add on’s like retraction valves or water line filters etc. But otherwise the basics are the same. 

 

The spinning of air driven handpieces handpieces is created by a few precise, but simple parts.

The spindle and chuck mechanism is a central shaft running through the center of a turbine and the part of the turbine which also holds the bur.

 

On the spindle is an impeller-  think of a propeller, which pushes air,   whereas an impeller gets pushed by air. 

 

Also on the spindle are 2 sets of bearings, which is how the impeller spins. For the most part the chuck/spindle and impeller are not the parts of the turbine that have issues, though they occasionally do, which we will get to later. It’s the bearings that are the culprit, and even that is a little misleading. It’s a part of the bearing called the bearing retainer that is the real culprit.  Picture something spinning at over 6,000 rotations every second, and think about how finely balanced this must be to spin so fast, and then think about it being unbalanced and what would happen, and how? 

How?   Contamination!  There are a few ways for this to happen. With the current technology of dental handpieces, we still have to contend with basic physics. Every time the practitioner takes his foot off the foot pedal an occurrence called “Suck Back” happens. The air is flowing forward through the dental lines, and when it stops a negative air pressure is created and the air flows backward for a moment. Contaminants from the mouth (saliva, blood, amalgam, composite, tooth etc., etc.,) have the opportunity to flow back into the turbine, and they do. On most current handpieces there is also no other real protection in the head of the handpiece for preventing other oral contaminants from entering the head through the small openings in and around the head.  These oral contaminants get inside the handpiece head and eventually get caught up in and on the bearings.  Back to when we were talking about the most finely balanced part of the turbine – the bearings, with these contaminants on them, they are no longer perfectly balanced.  

 

Catastrophic Failure. 

This term is used when the bearings and the piece that holds them in place, the retainer,  completely fails and the bearings will no longer spin at all. 

There is quite a process to get to this point, but the contaminants are where it begins.  With such a finely balanced part, any small “un-balancing” starts the process. The retainer, which hold each individual bearing in place, is generally made out of a softer material than the metal or ceramic bearings. Without issue the bearings spin freely inside the retainer and barely touch the sides of the retainer.  When unbalanced though, the bearings start to rub up against the retainer, and being a harder material, the bearings start to wear down the material of the retainer.  (The result of this wearing is what you see when you maintain your handpieces – the black gunk that comes out of your handpiece) The process of degradation starts with this slight unbalancing, but proceeds rapidly, as once the retainer starts to wear unevenly, it not only unbalances that particular bearing in its specific place, but that loose bearing unbalances the entire bearing set, which causes all of the bearings to run slightly off. This in turn starts degradation at each area where the bearing touches its retainer and cyclically the small degradation creates larger and larger unbalancing, until the point where the bearing hits “catastrophic failure”.   

This is the point when you are using the handpiece- and it basically just stops!!  Can anything be done at this point - - No, simply autoclave the handpiece and send it in to your preferred repair shop, as the bearings need to be replaced. 

Can it be prevented? Yes, at least to some degree.  Eventually as all things do, bearings (or more specifically the retainers) will simply wear down with age and use.  But you can prevent this from happening prematurely by simply keeping your handpiece as clean as possible. 

 And how is this done- Lubrication and Purging!!  As mentioned earlier many think that lubrication is simply used to prevent friction in a handpiece, and again,. that’s partially correct. The lubrication helps the bearings run in their retainers with less friction and less heat, but as important the lubrication is used to help clean out the entire turbine area of all the contaminants that build up during a procedure.  And as important in this process is the purging.   What is purging?   Purging is simply running your handpiece after lubrication. When you lubricate the handpiece, all, or at least most of the contaminants that gather in the turbine during a procedure get lifted off the internal parts and "float" up in the lubricant. The process of running air through the handpiece after it’s lubricated purges out most of these contaminants. 

Lubrication without purging?  Well - - Its better than nothing, but it’s really just half the job. It will prevent friction between the bearings and their retainer, but will do nothing to clean your handpiece. 

In essence, the contaminants that are in your handpiece will be floated in the lubricant, and then simply settle back down, and be cooked on during the autoclave cycle. Now there is an unbalancing agent cooked on to your bearings, with no way of being removed, and so starts the cycle of degradation. 

So – as important as lubrication is, equally as important is the purging after. 

 

With regards to the chuck, spindle and impeller: 

Again, the chuck is the mechanism that holds your bur in place.  Eventually the chuck mechanism will fail on a handpiece and burs will not be retained in the handpiece. This can be a potentially dangerous situation, as burs have been known to fly out of a chuck and fly right down your patient’s throat. So please make sure to check for bur retention each and every time before you use a handpiece to make sure that the bur stays locked in place. There is not much more to do than simply lubricate and purge your handpiece to make sure contaminants are not getting caught inside the chuck mechanism to prevent it from failing. Eventually it will fail, as it is a mechanical part, which will all fail at some point. 

The spindle and impeller rarely fail, and usually the only time they are changed is because on most brand handpieces these days the chuck is permanently attached to the spindle. When the chuck fails, not being replaceable by itself, the entire turbine needs to be replaced. Though there are a few brand handpieces where the chuck is a replaceable item independently from the spindle and impeller, but this is the exception to the rule. 

 

So, by following these simple steps, I can’t promise a perpetual use handpiece, but will guarantee that your handpiece will last as long as these modern marvels are meant to last. 

 

Make sure of the following: 

1-      Your air pressure is set to the manufacturers guidelines of your specific brand of handpiece. Most modern handpieces run at somewhere between 38-42 psi but some are very different, so read your instruction books and set your units to the proper pressure. If you prefer to have more torque, you can leave it at a higher air pressure, but understand you will send your handpieces in for repair more often. 

2-      Never use wipes or chemical disinfectants to clean your handpieces.                

-          Most wipes and cleaners leave behind a chemical precipitant, which gets in the small spaces and will build up and eventually cause issues. Most manufacturers suggest a light rinse in water or a cleaning cloth soaked in water or alcohol only to wipe the exterior of the handpiece. For handpieces with optics, an alcohol soaked cotton swab is recommended to keep them in clean and bright condition 

3-      Always use a good quality lubricant!! And the appropriate nozzle for your handpiece. 

-          Most lubricants on the market today, even some from the big manufacturers are nothing but about $3 worth of mineral oil in a $50 can. The better lubricants are either synthetic, or have a synthetic additive. If your handpiece had an oil pump to keep the bearings in a constant wash of mineral oil, it would be effective. Unfortunately, without a pump, the mineral oil does very little to protect your handpiece. Synthetic lubricants actually create a chemical bond with the bearings, activated by heat and friction. So they are much more effective in protecting your handpiece than a non-synthetic. Lubricants with a contact metal cleaner are even better, as they both clean and lubricate the bearings all at once. If you do use a cleaner/lube, MAKE SURE to shake the can before use, as the 2 parts will separate out like oil and water in the can. Spraying cleaner only, will damage your handpiece. 

-          Use the suggested lubricant nozzle to make sure your lubricant/cleaner gets delivered as the manufacturer designed it to. 

 

STEPS

 

1                     When done with a procedure, lightly wash the shell of the handpiece clean with water or alcohol 

2                     Shake your lubricant can and using the appropriate nozzle spray 2-3 quick bursts of lubricant into the handpiece, until you see lubricant escape the head of the handpiece. If you see contaminants, or the “discolored                               gunk” come from the head, re-spray the handpiece until it flows clearly. Using a cleaning cloth/paper towel, gauze, wipe the excess oil off the handpiece head. 

3                     Reconnect the handpiece to the dental unit (note: see purge unit) and run the handpiece for 10-20 seconds until you see no further lubricant running from the head. If you see more unclear lubricant flowing from the                               head, start again at step 2. If it is clear, bag and autoclave your handpiece according to the sterilizer manufactures instructions. Make sure to let the handpiece come down to room temperature before using it. NEVER                             use a hot or even warm handpiece as it will immediately start a cycle of degradation, even if you don’t notice any difference in the running or sound, the problem has started on a micro level and your handpiece will                               soon be in for repair. If you have to use a handpiece directly out of the autoclave under any circumstance – you don’t have enough handpieces. For every practitioner in the office, there should 1 handpiece in use, 1 in                             the autoclave, and 1 clean handpiece ready to go, and 1 spare in case something is in for repair – at minimum. 

 OK - - So lesson given, hopefully you can turn what you may have considered a bane into a boon if you follow the guidelines and make your handpiece less problematic, less costly etc, etc.  
If you have any questions or want to go over these ideas with your staff, please don't hesitate to contact us via email at Info@sabradent.com or call us at 800-888-4435, and me or one of my staff will be glad to walk you through it or answer any questions you may have.   We're glad to be of service . 

Quick note about purge units. 

If handpieces are maintained in the central sterile area and running a handpiece after lubrication back in an operatory is problematic, we suggest a handpiece purge station for your central sterile area. Purge stations are small devices that connect to an airline and can run air through, or purge the handpiece anywhere it is installed. With the appropriate adaptor and usually a small install fee from your technician, a purge station will usually cost less than $500 for the cost of the unit, the adaptor and the labor to install the air line, and the unit itself.  Figuring you can potentially save $500 in the first year alone in handpiece repairs, now that you are properly maintaining them, the purge station is generally a good investment over the long run and makes the whole process easier for staff that is doing the maintenance.  Note: There are systems called lubrication stations on the market for up to $5000. We generally don’t suggest these, as they basically do the same thing as the purge station does, but they do the lubrication part as well – and to spend an additional $4000 for a unit that simply replaces pushing the nozzle on the top of the can, simply doesn’t make sense to us. In addition, people tend to rely on these stations and assume that by using them, they don’t have to visually inspect the handpiece. If there is extra contaminant that is still in the handpiece – using a lubing station does not lubricate the handpiece again to purge it out. They rely on the unit to do all of the maintenance, and do not take the responsibility themselves, which can lead to less than perfect conditions.