Dental Bearings
Most highspeed dental handpieces are driven by small, 
highly specialized, air-driven turbines. These turbines ride on ball bearings, and rotate at approximately 400,000 RPM in most cases. Some Kavo Highspeeds operate at upwards of 420,000 RPM. This is extremely fast (thousands of times faster than the engine in your automobile). With this speed, the margin for error is very small.
highly specialized, air-driven turbines. These turbines ride on ball bearings, and rotate at approximately 400,000 RPM in most cases. Some Kavo Highspeeds operate at upwards of 420,000 RPM. This is extremely fast (thousands of times faster than the engine in your automobile). With this speed, the margin for error is very small.
Handpiece bearings are some of the most highly scrutinized in the bearing industry due to their high speeds when in use, and expected exposure to the constant heating and cooling of the autoclave cycle between uses. Tolerances (distances between rotating and stationary parts) are some of the very tightest in the industry. The Annular Bearing Engineering Committee (ABEC) scale is a system for rating the manufacturing tolerances of precision bearings. Bearings rated under the ABEC system are rated with a number from 1 to 9.
(high number = tighter tolerances = more expensive bearing).
Dental bearings should be rated at ABEC 7 or better.
The two types of bearing most used in the highspeed handpiece application are called angular contact and radial. These terms refer to the type of inner race, or ring. Angular contact bearings are typically preferred by handpiece manufacturers, but some applications dictate using the radial type.
Ball bearings are, in most cases, stainless steel with some sort of low friction component imbedded to make them resistant to failure when exposed to poor lubrication practices. The balls ride in a cage, usually made of synthetic materials like phenolic, polymide, or torlon. Phenolic cages work especially well by absorbing lubricant for added friction resistance.
The use of ceramic balls is becomming more prevalent now in dental bearings. Ceramic handles heat and friction very well, and will not expand to the extent that steel does. Ceramic sealed bearings packed in a high temperature grease are considered lube free. Star has used these for years with great success. Manufacturing difficulties make ceramic bearings considerably more expensive.
Timken, Barden, and New Hampshire Bearing produce very high quality bearings in our opinion, and are available to most dental equipment dealers.