Replacement of O-rings
O-rings are used extensively in dental equipment - everything from your handpiece to your sterilizer uses them. They can be made from a variety of materials and come in a vast array of sizes. Many people also refer to them as gaskets, although o-rings are not truly gaskets.
An o-ring will always be circular and have a circular cross-section. The cross-section can be thought of as the shape of the material that forms the “o.” If you cut an o-ring and look at the end, the shape you see is the cross-section.
Sizing
O-rings come in a variety of sizes and can have many different applications. In our catalog, the o-rings are shown at actual size. To determine the correct size, you can simply lay an old o-ring on the page for identification.
O-ring manufacturers also use a special numbering system for standard o-rings. Standard o-rings have a 3 digit number to correspond to the size. The larger the number, the larger the o-ring. Many equipment manufacturers incorporate these numbers into their part numbers, which simplifies cross-referencing.
For example, A-dec part #030.002.02 corresponds to o-ring number 002 and American Dental Accessories part #18-OR-002. NOTE: while the sizes are standardized, the applications are not. A “002” size o-ring could be used on many different things in many different brands of equipment.
When choosing an o-ring, always look for the correct size, rather than describing your particular application. Having an o-ring kit on hand, can also help you out when looking for a replacement o-ring.
Maintenance
Most o-rings are made in a variety of materials depending on the application. In a typical dental unit, most of the o-rings are made out of some type of synthetic rubber. These dry out over time.
O-rings should be regularly lubricated with a silicone-based lubricant to maintain elasticity and prolong their life. Petroleum-based lubricants (such as Vaseline) can actually accelerate the drying out of o-rings and should not be used. While it isn't practical to completely disassemble your dental unit to lubricate all the o-rings, certain components can be more prone to wear and are more readily accessible.
- Vacuum Valves: The o-rings on vacuum valves can be simply accessed without using tools and should be lubricated at least once a week. See image above of how to disassemble a valve to lubricate.
- Air/Water Syringes: If something is sticking, (like a syringe button, or your foot control) try dismantling to expose the o-rings and generously lubricate with silicone-based lubricant. Many times, this will restore your equipment to normal function quickly and easily.
Read more about o-rings in Practice Tips #100. If you have questions, please ask us. We offer every day low prices, free technical support, and friendly service 64 hours a week. Call 1-800-331-7993 or order online now!
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