Practice Tips #30: Air/Water Syringe Installation

Installing a new air/water syringe onto a dental delivery system is a very straight-forward affair. Whether replacing an existing syringe or adding a new one, anyone can install a syringe in minutes.

Tools you will need:

  1. Sleeve tool– a specialized tool used to slide the sleeve clamps over the tubing once the tubing is on your barbs.
  2. Sharp knife – the sharper the better, a box knife, Exacto or something similar is preferred. You will need to use this to trim the twin lines of the syringe tubing.
  3. Diagonal wire cutter or strong scissors – only necessary if adding a syringe to a unit. This will be used to cut existing air and water supply lines so that the tubing for the new syringe can be attached.

We’ll start assuming your adding an extra syringe to your unit. You can skip this if simply replacing an existing syringe and jump to “installing the syringe” below.

When adding a syringe to a unit, in addition to the syringe, you’ll also need syringe tubing, two barb tees (we recommend our part #14-61 as it can be configured with either small or large barbs so you can splice into any size line), as well as a suited to your unit (assuming you don’t have an empty one already). When purchasing tubing, 5’-7’ is a typical length but you should always carefully measure your existing lines or the distance from your source of air and water to the patient (when in doubt, a little extra is always a good idea).
Once you have everything, you’ll need to open your unit and find a live air and water line. The lines are typically color-coded, water lines are blue and live air lines are yellow. Some units use different colors, call and speak with our techs for advice on yours. A typical unit is pictured below:

There are typically several air and/or water lines that are viable within any unit. Before cutting the lines to splice into them, detach them from whatever valves to which they may be attached to see if there is pressurized air or water in the line. If there is, they will be good lines to use. If possible, you can also splice into an existing syringe air and water lines as well. This will always work.

Once you’ve identified an air and a water line, turn off your unit and exhaust the line pressure by running a handpiece or holding down both buttons on your existing syringe until flow stops. Next, cut the air and water lines using a scissors or wire cutter. Screw the correct size barbs into your barb T’s (making sure to use the washers) to match the lines you’ve identified. In the above example, the water line is a smaller (1/8” o.d.) line and the air line is larger (1/4” o.d.) so one T will need to be configured with all small barbs, and the other with 2 large and one small barb (syringe tubing consists of two small lines, so you’ll always need at least one small barb on your “T’s”).

Slide the appropriate sleeve clamp over each end of the tubing you’ve just cut. NOTE: one side of the sleeve clamp will be beveled, when attaching tubing to a metal barb (as in our example) the beveled end should be facing towards the barb. Dip the end of the tubing in hot water and lubricate the barb with a little silicone lubricant or a similar material. Slide the tubing over the barbs pushing the tubing on a little over half way. Using a sleeve tool slide the sleeve clamps down over the tubing and barbs. When the sleeve clamp is pushed on, the tubing will be pushed with it to fully seat over the barb.

Next, using a sharp knife, score between the lines of the syringe tubing and pull the two lines apart for a few inches. Then, use your knife to trim the excess material from the tubing.

Once the excess material has been trimmed, slide a sleeve clamp over each of the individual lines of your syringe tubing. IMPORTANT: While you now have your syringe tubing connected to your air and water lines DO NOT CONNECT YOUR NEW SYRINGE YET. First, feed the syringe tubing through an access hole in the bottom of your unit.

Now that the tubing has been fed through the unit, separate and trim the two lines you did before. Be careful not to split the tubing too far. While this end will go inside the syringe handle, only a few inches will be hidden so do not split the tubing more than an inch or two. You are now almost ready to:

Install the Syringe

For those of you replacing an existing syringe, at this time, shut your unit off and depress both buttons of your existing syringe until all flow stops. Unscrew the syringe handle and cut the tubing as close as possible to the syringe head. Discard the old syringe and handle.

Trace the lines of the syringe tubing to identify which is air and which is water. Once the lines are separated and trimmed, slide a sleeve clamp onto each line. Slide the sleeve clamp a little farther down on the water line than on the air line (this helps you keep track of which line is which). The barbs on your new syringe are metal, so you’ll want the beveled end of the sleeve clamp facing the end of the tubing (where the syringe will be attached).

Unscrew the handle from your new syringe and slide the handle over the tubing. Next, attach the air and water lines of the syringe tubing to the barbs on the syringe head. The water line will usually attach the the left-hand button (when looking at the back of the syringe head) and the air line to the right-hand side. Attach the water line first (the sleeve clamp is pushed farther onto the tubing) by sliding it over the barb. You can dip the end of the tubing in hot water and/or lubricate the barb with some silicone lubricant to make it easier to slide the tubing on. You’ll want to slide the tubing only about 1/2-3/4 of the way on. Once the water line is attached you can then attach the air line using the same procedure. After both lines are attached to the barbs, use a sleeve tool to slide the sleeve clamps over the tubing and barbs. The sleeves will push the tubing the rest of the way onto the barbs when they are seated.

Slide the syringe handle up and hand-tighten it onto the head. Turn your unit on and test the syringe for function. Put the cover back on your unit and voila! You’ve got a new syringe!


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