A while ago, I had the opportunity to repair a small bubble in an old composite restoration, and I got to thinking you might like to know how I use air abrasion to do this type of repair.

I don’t know how many times you see this, but I frequently see small holes in old composite restorations. In many cases, the margins look good. Everything looks good about the restoration except where there was an air bubble when the composite was placed and now there is a little hole on the occlusal surface. Food can get trapped and staining can occur in the hole, but the hole doesn’t descend into the tooth. And sometimes I see a little gap on the margin of an old composite with staining or early decay. In both cases, I don’t want to remove the entire restoration.

I use a lot of air abrasion in my practice, and in particular, I find it is wonderful for repairing old composite. I have the EtchMaster® from Groman. It’s a little handpiece that is super easy and convenient. It makes using air abrasion chairside something you will want to do every day.

Use 50-micron aluminum oxide air abrasion to clean out the stain, etch the old composite, and etch the tooth. If any tooth structure is to be etched, this air abrasion is a replacement for phosphoric acid. So, in one easy step, you have prepped the tooth and the composite. A plus of this technique is that local anesthetic is not needed if the hole does not extend into the tooth.

Now you can go in and use your dentin adhesive and replace your repair composite. Today, dentin adhesives contain MDP or PMMA which is the chemistry we need for the new composite to bond to the old composite. If I were to repair a composite restoration with a handpiece and a burr, I would not get the same bonded interface between the new resin and the old resin.

For both ease, patient comfort, and the best bond, I choose to treat previously polymerized resin with air abrasion and then some sort of resin that contains either MDP or PMMA.

Chair-side air abrasion has numerous advantages, especially today when we use adhesive retention so much of the time.

The advantages for many years have been outweighed by the logistic challenges. With the advent of small, lightweight, easy to use air abrasion handpieces this is no longer true. When I became aware of the etchmaster I was skeptical, but I am now a believer and use air abrasion int he operatory all day long.

The Clinical Applications

One of the first things that many of us will utilize air abrasion for is to “etch” zirconia restorations for bonding during final seating. The only way to prepare the inside of a zirconia restoration is with 30-50 micron aluminum oxide. The particle size and type is critical. The ideal pressure is 1 bar (15psi). Next on my list is to clean tooth preparations prior to bonding and cementation. To me there is no better way to assure the removal of temporary cement and prepare a tooth for maximal adhesive retention than with 30 micron aluminum oxide.

My list goes on as I have started to prepare small class one cavity preparations using small glass beads in my chair-side unit. Cleaning out the occlusal grooves prior to a sealant and etching un-prepped enamel for anterior esthetic composite margins are other uses. In addition sodium bicarbonate can be used to remove stain. Now that I have a convenient, easy to use unit, I find more and more reasons everyday.

Air Abrasion Made Easy

When I first began to experiment with air abrasion the biggest challenge was the equipment and managing the logistics.  The Etchmaster is a small 3 to 4 inch attachment that connects to either a 3 or 4 hole line on your unit. The pressure is precisely controlled, for great clinical outcomes, and it means the patients mouth is not full of powder when you are done. The powders come in pre-filled tips that slide into the top of the hand-piece. You can choose from a variety of sizes and particle types and sizes. This means no more filling a reservoir with powder, wondering if you have too little or too much. It also means not wondering what particle type and size is in the reservoir the next time you go to use the unit.

Have you explored the clinical advantages of air abrasion? How has this been beneficial in your practice?