Page 72 - ENGINEERING REVIEW APRIL 2022 DIGITAL MAGAZINE

CASE STUDY
#CERAMIC BEARINGS

Hybrid ceramic bearings in dental

instruments: The benefits

Dentistry tools can rotate at speeds of up to 400,000 rotations per minute (RPM), therefore high-speed bearings
are essential in these applications. When the incorrect bearing is specified for dental instruments, it can lead
to surface wear and eventual breakdown of the tool all together. Here Chris Johnson, managing director of
miniature bearings specialist SMB Bearings explores the benefits of using hybrid ceramic ball bearings in dental
applications and how these bearings can prolong the life of equipment.

Angular or radial: what’s the difference?
Bearings used in dental applications are available in a variety
of forms and materials, leading to a discrepancy in quality and
varying price points. Dental bearings are usually designed with
extreme precision, accuracy, and reliability in mind. In essence,
there are two types of miniature bearings used for dentistry
equipment: radial contact and angular contact bearings. These
bearings are used differently, dependant on their purpose. The
difference between these two types of bearings lies within
the retainer type — radial bearings use what are called crown
retainers, whereas angular bearings use full retainers.
Radial bearings are beneficial because of their ability to be
axially loaded from either side, while on the contrary, angular
bearings can only be axially loaded from one side although with
greater loads than the radial type. Although both bearing types ceramic balls create less centrifugal force when running at
are suitable for dental instrument applications, bearings with an high speeds, causing minimal wear to the raceway and outer
angular contact configuration work best because of their ability ring. What’s more, the surface wear of ceramic bearings is
to bear ‘combined loads’ in both radial and axial directions. significantly reduced due to ceramic and steel being different
in their material composition. Dental equipment with hybrid
Ceramic balls ceramic ball bearings are also quieter and require little to no
When deciding on which bearings are best for dentistry tools, lubrication because of their frictionless characteristics.
using hybrid bearings with silicon nitride balls may be the best While using ceramic bearings within dentistry equipment
option. A significant advantage of hybrid bearings is that their and in the wider medical industry can be deemed as more
ceramic balls are typically harder than heat-treated steel balls, expensive than steel bearings, they are typically made to
making them less prone to causing external damage or bearing high-quality standards. If high-quality bearings are used within
failure due to debris from surface wear. dentistry equipment, this can prevent instrument failure and
Another advantage which sets ceramic balls aside from ball prolong instrument life for the long term.
bearings composed of other materials is that they perform
at cooler temperatures. In turn, this can prolong the life of a
dental instrument. Due to silicon nitrate’s non-porous molecular
structure, ceramic balls are almost laminar — meaning that
they can run at high speeds of up to 400,000 RPM without
concern, as well as making them resistant to corrosion that
harsh chemical sterilisers might cause.
Ceramic balls are lightweight and are around 60 per cent For more information
lighter than steel balls of similar sizing. As a result of this, Website: www.smbbearings.com

70 | APRIL 2022