Dr. Nammy Patel from Green Dentistry in San Francisco answers the question — what’s wrong with metal crowns? She explains how they can lead to gum recession, and she talks about the benefits of Emax crowns.

Dr. Nammy: Well, the problem with metal fused to porcelain, or metal, is that the metal actually causes an oxide reaction because it’s not pure metal. Even the gold isn’t pure gold. The gold is going to have several other metals associated with it to give it the strength it needs in order to resist the biting forces because gold itself is actually really soft.

So in order to give it the hardness, it has to be combined with silver, tin, a bunch of other things. And same thing with the porcelain fused to metal, it has a metal base and then a porcelain on top. And again, all of those will cause oxide reactions. And those oxide reactions basically are an inflammatory response. Your body doesn’t like metal. It doesn’t want metal. So it actually fights it… it eats away the gum tissue, and that’s when you get something called the gum recession.

The thing with porcelain is that the porcelain is made in a laboratory and it’s stacked on, so it’s baked on, so there’s layers and layers of the porcelain. And so, what’s common with that is that the porcelain breaks. So my favorite type of biocompatible material is actually an Emax crown, and those are really great because they’re compressed at high pressure and temperature, and they’re inert so they don’t cause any sort of problems at all in the mouth.