Attack of the Collagen Eaters!

The collagen eaters have been released! When you prep a tooth — actually, when you create injury to any bodily tissue — stuff called matrix metalloproteinases get released. These substances consist of secreted or membrane-bound zinc endopeptidases and include collagenases, gelatinases, and stromelysins.

(If you experienced a biochemistry flashback from that previous sentence, I can assure you that the nausea won’t last. Just lie down until the feeling passes. When you think you’re ready, sit up slowly, take two deep breaths, come back, and complete your reading. Everything will be OK.)

If you felt an electric shiver of excitement up your spine just thinking about the biochemical mechanisms of matrix metalloproteinase, here are two articles that might serve to continue that excitement:

• Effect of dentin etching and chlorhexidine application on metalloproteinase-mediated collagen degradation
• Limitations in bonding to dentin and experimental strategies to prevent bond degradation

For dentists, the problem with metalloproteinases is that they destroy collagen — the stuff you’re counting on to bond your resin materials to dentin. Fortunately, there’s a way to reduce the impact of these biochemical assassins: Prep every tooth for a crown and cement it. OK, we’re not going to do that, so we have to try to inhibit the action of these collagen eaters. Fortunately, there is a real way.

Many of us have been minimizing the effect of the matrix metalloprotienases for years without even knowing it. Turns out that chlorhexidine can reduce the activity of these substances, so those of us who’ve been cleaning the prep with a disinfectant have unknowingly helped our bonds stay bonded. The literature regarding this action of inhibition with dental materials has been done exclusively with chlorhexidine, but the medical literature is replete with examples of this inhibition using a 3% glutaraldehyde solution. Because Gluma is a 5% solution, I bet it inhibits the dental collagen eaters too.

Ed McClaren was at the center recently participating on a panel for our Visiting Faculty day and I had an opportunity to talk with him regarding this. He shared that they’ve found washing the prep with a 2% chlorhexidine solution first, then using Gluma, provided a 10% increase in bond strength over chlorhexidine alone.