Zirconia in Dentistry
There’s a new big player in dentistry and it’s name is Zirconia. It’s a material
for dental crowns, used in the form of zirconia dioxide. (It is stabilized by another metal oxide, yttrium oxide.)
So what are the advantages for this material that has now captured a 50% of the dental lab market?
It is hard. This is one of the hardest dental materials we’ve ever had, and it will hold up very well with strong chewing. It also holds up well to the oral fluids.
Zirconia is tooth colored. When I do esthetic crowns on front teeth I like using porcelain fused to zirconia because I don’t have to worry about the metal showing through as would happen with traditional metal alloys used in the past. Zirconia has been developed to make it look as nice as the porcelain crowns and provides more strength. In other words, you don’t have to worry about porcelain chipping off of the crowns.
Are there any down sides?
One problem is cutting them off. They are SO hard that normal burs (the part of the dental drill that cuts the tooth) won’t cut it. I have to order special burs and even those get worn out very quickly as well. Cutting the crown off would happen if there is porcelain that chips off, or there is decay around the tooth.
A more serious problem is that the zirconia will wear out the opposing tooth. I attended a seminar earlier this year, and the clinician showed slides of the teeth opposing some of these crowns after they have been in the mouth 5-6 years. The result is that the opposing teeth will need a crown in short order; not what we want! Other materials, like cast metals, are less abrasive and will not wear down the opposing teeth (though they won’t be white).
I think zirconia is here to stay a while. Dentistry is a very creative field with regard to our instruments and materials. In another 20 years we’ll probably find something better as we always seem to do.