I am a holistically-minded person and am very cautious about anything I put in my body. At my last dentist appointment, I found out I need a crown. As I began researching it looks like ceramic crowns are best. Is this actually made of glass? I haven’t been able to get a straight answer it seems. I want to stay away from any metals or lithium. I am adamant about this because of my thyroid condition. Any insight you could provide would be greatly appreciated.

-Sheila from California

Sheila,

Ceramic crowns do not contain any metals. But, due to the nature of your question, I’m wondering if you are also insistent on avoiding metal ions as well. Unfortunately, this is a near impossible request, since every dental ceramic contains metal ions.

Here’s some background chemistry information to consider. Iron is a metal. Iron oxide is actually iron and oxygen combined, which is rust. Technically, rust is not a metal. But it does have metal ions in it. Now, you do not want to eat metallic iron. But the ions for iron are a key component in our diet and sustain our bodies. For example, our blood contains hemoglobin and also is responsible for it being red in color.

Stay with me. Another relevant example is sodium. It is a metal, which is toxic when ingested. But as a metal ion, when it is combined with chlorine, the product is salt. Other basic essential metal ions include calcium, potassium, zinc and magnesium. And there are a whole host of others.

So, to go back to your initial concern about lithium. It is a metal that is highly reactive. Therefore, doesn’t exist naturally, unless it is combined with the ion form and with other elements. So, lithium disilicate is a ceramic. It is extremely strong and is very successfully when used in a crown.

Another form of ion combined with oxygen is zirconia, which comes from the metal zirconium. A zirconia crown is one of the strongest materials used in dental crowns today.

When you mention Vita crowns. This is just a certain brand of porcelain. Porcelain crowns do contain metal ions. When the porcelain crown is bonded to the tooth, it can end up being stronger than your natural teeth. Kaolin is a clay that contains silica and aluminum oxide. Notice it is another ion, not aluminum metal.

You also asked about if the crowns were comprised of glass. The answer is no. Glass or silicon dioxide, won’t hold up as a dental crown. Some brands of crowns, like Empress crowns, may use glass in them. For example, in the Empress crowns, leucite glass contains aluminum tectosilicate.

So, those are the facts. I know it’s a lot to digest. But you seem to be a researcher. So feel free to use what I have provided here, along with what you have already compiled to best determine which type of crown is best for you.

In closing, considering your slant toward holistic practices, zirconia crowns would likely provide the least biological impact. Thank you for your question. Hopefully this information was helpful.

This post is sponsored by Houston cosmetic dentist Coleman Dental.