Assistina - How does this thing work?

By: Steve Aucremann


W&H Assistina 301 PlusAs you know handpiece lubrication is the key to bearing life and handpiece performance. Many of your customers may use the Assistina and it will help you to know how this unit works. First of all, the cleaner on the right side is primarily alcohol and is used to clean and disinfect the water line in the handpiece - it has no effect on the turbine or bearings. The oil on the left side is injected into the drive air with the exhaust blocked off, so that it is forced through the turbine and the bearings, and out the back cap and around the chuck opening by a blast of air which lasts about 30 seconds. This forces out any debris and leaves a film of oil to lubricate the bearings.


The Assistina operates like this. With a hand piece in the Assistina and the proper fluids in the reservoirs you press the start button holding it down for 2 seconds then release. When you press the button a 2 chambered pump is activated, pushing a small amount of cleaner up to the water line of the handpiece. The air you hear is blowing the cleaner through and out of the handpiece. When you release the button, the second chamber of the pump pushes the oil into the drive air line *(the reason you hold the button for 2 seconds is because the oil is thick and needs time to draw into the pump chamber). Again the air is blowing the oil through the handpiece to force out any debris and leaving behind a film of oil to lubricate it.


The primary problems happen here. When the air is pushing the oil out through the bearings it is also pushing back against the oil in the tube coming from the pump and if there is any leaking along the line it pushes back the oil so the next time there is no oil at the end of the line to lubricate the handpiece. Now the Doctor thinks he has lubricated the handpiece, but he hasn't. Usually this goes on till the Doctor says that the bearings you just put in aren't lasting long enough. I think you should be pro-active, and check the Assistina for proper operation before you repair the handpieces.


Here is the easy way to test the unit. Take off any attachments or adapters so you can see what looks like a standard e-type connector inside the Assistina. First, look to see that it has 2 o-rings in good condition. Shine a flash light on the connector and press the start button. You should see the burst of cleaner spray down from the connector. When you release the button then you should see a mist or fog of oil. if these are not present close the cover and press the button repeatedly until you can see the green indicator balls popping up - the right one when you press and the left one when you release the button. Now repeat the first test, if it still is not pumping properly, it needs repair. If it works then go away for 30 min. then come back and test it again (sometimes it leaks very slowly). If the unit is working properly then you will get the same burst of fluids every time. If the Assistina is not working just send it to us, we can fix it.


* I am told by by technicians in the field that not holding the button for 2 seconds is the leading causes of malfunction.


Here are a few more tips and tricks.

  • You really can't over-lubricate so tell the Doctor to push the button 2 or 3 times if he is not sure enough oil is coming out.
  • Many times people put the wrong liquids in the unit I have even seen things like bio-cide and film developer in these units which can be very bad. Open the chambers and check the fluids for contamination.
  • The Assistina also lubricates e-type attachments and has a turbine and drive-dog to turn the attachment while the oil is being blown through. Pressing the start button multiple times is always a good idea for these.
  • W&H makes many different adaptors for different handpieces. Be sure they have all the proper o-rings.
  • Always use the proper lubricant in the Assistina. The viscosity of the oil is key to the proper function of the unit.

Assistina is a registered Trademark of A-dec Inc. manufactured by W&H Dentalwerk (Austria) and imported and distributed in the United States by A-dec. These comments are from our own experience and not necessarily the opinion of A-dec or W&H.