Dental ball bearings
Ball bearings that are used in a variety of dental instruments can be divided into two groups, depending on their speed of rotation. It is measured with RPM (Revolutions per minute) - a measure which describes how many turns are completed in one minute around a fixed axis:
- Bearings with RMP from 100,000 to 500,000 are called HIGH SPEED dental bearings,
- Bearings with RPM from 25,000 to 100,000 are called LOW SPEED dental bearings.
All dental rotors/cartridges are assembled with High Speed Ball Bearings. The technical operation of a rotor is highly dependent on the choice of high speed ball bearings.
When selecting bearings one has to be particularly sensitive to the configuration of bearing (1), type of balls (2) and the bearing manufacturer (3).
Ball Bearings are available with Angular contact configuration ? Angular Contact Ball Bearings (ACBB) and Radial contact configuration ? Deep Groove Ball Bearings (DGBB).
The difference between the angular and radial bearings is in the retainer type which defines the support of load from axial and radial direction.
Radial ball bearings (fig. 2) include crown retainer and are more convenient to use because they may be installed and axially loaded from either side. Angular contact ball bearings (fig. 1) include full retainer and can only be axially loaded from one side, but better support "combined loads" (loading in both the radial and axial directions). Angular contact ball bearings perform better at higher speeds. On average they operate longer than radial bearings.
(2) Type of balls? Ceramic or Steel
There are Ceramic ball bearings which include hardened steel rings and silicon nitride (ceramic) balls, and Steel ball bearings with steel rings and steel balls.
The advantage of using a hybrid ceramic ball bearing (fig. 3) is that it runs cooler and extends bearing life.
In addition, a ceramic ball is approximately 60% lighter than the same size steel ball. As a result, the lighter ceramic ball-set generates less centrifugal force when operating at super-high speeds, which minimizes wear on the raceway of the outer ring. Surface wear is further reduced because ceramic and steel are such different materials. Ceramic balls are harder than heat-treated steel balls, so it?s less likely that external contaminants or bearing wear debris will damage them and cause the bearing to fail. Also, a hybrid ceramic bearing operates better than an all-steel ball bearing in low-lubrication conditions.
In conclusion the benefits of ceramic angular contact bearings are:
- Longer lubricant service life
- Lower operating temperatures
- Increased speed rating
- Reduced weight
- No impact on assembly processes
- High stiffness
- Longer life
- Lower noise level (up to 25%)
Because of much better technical performance OEMs assemble their rotors with Angular Contact ball bearings. On the other hand Deep Groove ball bearings (radial contact)
are mainly used in several service-technical organizations offering handpiece-repair or by dental dealers offering low cost rotors/cartridges for various handpieces.
When choosing rotors assembled with angular contact bearings you get the same performance of a rotor as using the original one, but for much less money. We recommend Angular bearings to every our customer, but we also offer rotors with radial bearings as well.
When buying aftermarket dental rotors/cartridges/ turbines or dental bearings you have to pay attention on bearings origin. On the market you can find many providers of dental bearings offering bearings of unknown origin. These bearings mostly come from questionable productions or are produced for low standard markets. We strongly recommend you to ask providers of dental rotors which ball bearings do they sell and assemble on rotors.
V&KL dental rotor offers you rotors assembled with top quality ball bearings, which are produced by Myonic, the producer of bearings for Original Equipment Manufacturers, like Kavo, Sirona and W&H. Bearings can also be purchased as a stand-alone product.