High-speed bearings are required in dentistry instruments because they may revolve at speeds of up to 400,000 rotations per minute (RPM). When the wrong bearing is specified for dental instruments, it can result in surface wear and, eventually, tool failure. Chris Johnson, managing director of miniature bearings specialist SMB Bearings, explores the advantages of employing hybrid ceramic ball bearings in dental applications and how they can extend the equipment's life.

Angular or radial: what's the difference?

Bearings for dental applications come in a variety of shapes and materials, resulting in a wide range of quality and price points. Dental bearings are normally made with a high level of precision, accuracy, and dependability. Radial contact and angular contact bearings are the two types of micro bearings utilised in dentistry equipment. Depending on their purpose, these bearings are employed in various ways. The retainer type distinguishes these two types of bearings: radial bearings employ crown retainers, whereas angular bearings use full retainers.

 Radial bearings are advantageous because they may be loaded axially from either side, whereas angular bearings can only be loaded axially from one side, however, with greater loads than radial bearings. Although both types of bearings are useful for dental instrument applications, angular contact bearings perform best since they can handle 'combined loads' in both radial and axial directions.

Ceramic balls

When deciding on which bearings are best for dentistry tools, using hybrid bearings with silicon nitride balls may be the best option. A significant advantage of hybrid bearings is that their ceramic balls are typically harder than heat-treated steel balls, making them less prone to causing external damage or bearing failure due to debris from surface wear.

 Another advantage that sets ceramic balls aside from ball 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 lighter than steel balls of similar sizing. As a result of this, ceramic balls create less centrifugal force when running at high speeds, causing minimal wear to the raceway and outer ring. What's more, the surface wear of ceramic bearings is significantly reduced due to ceramic and steel being different in their material composition. Dental equipment with hybrid ceramic ball bearings are also quieter and require little to no lubrication because of their frictionless characteristics.

 While using ceramic bearings within dentistry equipment and in the wider medical industry can be deemed as more expensive than steel bearings, they are typically made to high-quality standards. If high-quality bearings are used within dentistry equipment, this can prevent instrument failure and prolong instrument life for the long term.