Why Adhesive on Your Instrument Is Negatively Affecting Your Bond Strength

Despite the long list of benefits composite resins have brought to dentistry, one of the continued frustrations for clinicians is handling. Although newer composite placement instruments coated with aluminum titanium nitride have improved the ease of placement, composite is still … sticky! It can be difficult to ensure adaptation to prep walls and sealed margins when you condense the material and pull back your instrument. It’s not uncommon to pull the recently condensed composite back out of the prep!

One solution that seems to be a popular one is to coat your placement instruments in the adhesive you used just before placing the composite. While it does keep the composite from sticking, it comes with some detrimental side effects.

Adhesive systems containing solvents like acetone or ethanol (found in most single-component and self-etch adhesive systems) are evaporated when you air-thin. When you place adhesive on an instrument, the solvent isn’t evaporated, which in turn inhibits polymerization and can alter the final shade of composite. If you remember my past article discussing glutaraldehyde, HEMA is found in a lot of bonding agents, which also affects polymerization, thereby weakening it. HEMA can also alter the final shade, increasing the chroma.

A great alternative that works arguably better at improving composite handling is the use of a composite wetting resin. Wetting resins are 45% filled, light-cured liquid resin. They’re great for incremental layering and for improving the adaptation of composite during placement. Wetting resin is an extra product to add to your mix, but it won’t decrease polymerization and it improves the color stability at completion.

I have my assistant place a very small amount (less than the size of a pea) on a clean surface on the back side of her glove, and then I dip either my instrument or brush in it. You need very little! Too much of it will actually make handling the composite more difficult. Enough to give the instrument a glossy or wet appearance, but not so much that you can see the material is sufficient.

I use Brush and Sculpt by Cosmedent in my practice, but there are several of these wetting agents available on the market today.

So next time you go to place composite, if you’re struggling with stickiness, think twice before you slop some bonding agent on that instrument!