Practice Tips #67: Syringe Tips 101

Air water syringe tips are one of the most common products dentists and hygienists use in dental offices. So let's get to know more about the differences between syringe tips and which ones will work best for your practice.

The basic design of the standard air water syringe tip has remained unchanged for decades.  The air water syringe has two concentric passageways, one for air (usually the outer passage) and one for water (usually the inner passage).

The central tube (see image below) is for water. On most standard tips, this tube is longer and projects out the back of the tip. This design allows the water tube to penetrate a small o-ring (#01-06) inside the syringe head to help keep the air and water separate.


On many disposable tips, the inner water passage is the same length as the rest of the tip; this means that these tips will require a special adaptor to help keep the air and water separate. If used without an adaptor, they are much more prone to cross-over (See Practice Tip #50 & Practice Tip #51). This is one reason that autoclavable tips will usually deliver superior performance.

On most syringe tips, air moves through the outer passage of the tip coming out at the end. Sometimes the air is expelled through a simple gap but sometimes several holes are used (this aspect of the design can vary widely). Most metallic tips will have a series of holes regularly spaced at the end of the tip to allow expulsion of air (see image below). The regular and consistent spacing of these holes provides a consistent spray pattern (when spraying both air and water mist). As a cost saving measure, many disposable tips simply use the natural “gap” between the inner water line and outer air line of the tip to allow air to escape out the end. Relying on this gap provides inconsistent spacing and an irregular and inconsistent spray pattern.

As mentioned, syringe tips at their most basic are simply an assembly of two concentric tubes. These are round. They go into a round passage in the air water syringe and are normally secured with o-rings.  This means you’ve got a round tube in a round hole. It will spin. Many practitioners like to use the syringe tip for retraction and will push on the cheek with the syringe tip. If pushing with the tip, rotation is not desired. Most syringes are designed for quick changing of tips (as the tip should be changed after each patient) which does not normally allow for a mechanism to reduce the ability to spin if pushed on. The DCI rotation lock tips (#01-97) are an exception to this.

The rotation lock tips have a series of “dimples” (see image below) around the perimeter of the tip which will lock in with the ball bearings of the DCI syringe holding mechanism (“collar”) making it harder for these tips to spin. These tips will only work in a DCI syringe (#01-01Q or #01-85) which has 6 ball bearings in the collar to secure the tips. The ball bearings are retracted to change tips, so using a design that incorporates the ball bearings does not preclude quickly changing tips either.

With most other syringes, two o-rings (#01-04) are used to hold the tips in place. On some of these, one o-ring may be replaced with a cone (#01-21). Along the length of the cone is a slit (see image below). This slit provides lateral tension making it harder to spin the tip. Some syringes can be adapted to use a cone instead of an o-ring if you wish to minimize tip spin. Normally, use of a cone will make it more difficult to change tips, but it shouldn’t prevent quickly changing tips. Consult with our staff and we will help you determine if you  can incorporate a cone in your syringe.

As you can see, many aspects of the tip design affect syringe performance. Keep your needs and uses in mind when purchasing tips and syringes.

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