We’ve talked before about the remarkable durability of CEREC restorations, how they are the only restoration that lasts longer than gold fillings. But what makes CEREC restorations so durable? It’s a material secret that we’re proud to share.
Not Quite Diamonds
CEREC is made of ceramic, but it’s an advanced ceramic composite that is designed to take some punishment. One of the major ingredients in CEREC blocks is aluminum oxide (Al2O3), which is also called alumina. When found in nature in its crystalline form, it’s called corundum. Never heard of it? That’s understandable, but you’re probably familiar with two of its variants: sapphire and ruby.
In addition to being a gem of great value, corundum has something else in common with diamonds: it’s very hard. While diamonds are a 10 on the Mohs hardness scale, corundum is a 9 (that’s not quite as good as beating gold, but it’s close). For comparison, your natural tooth enamel is about a 5.
High Impact Applications
In addition to its natural hardness, alumina is notable for some of the applications it’s used in. Alumina is one of the most common ingredients in ceramic body armor and tank armor. It’s not used in its pure form, but is instead combined with other ingredients to make a very durable armor capable of deflecting the impact of bullets and even armor-piercing tank shells.
Check out this recent test of an alumina-based body armor to see how well it works.
A Composite Designed for Your Teeth
In order to make alumina suitable as a restoration material, it can’t be used pure. Think of it this way: would you really want something so hard that it wears away your natural tooth on the opposite side. So the alumina is softened by blending it with other ingredients. This blending also makes sure that alumina has the proper translucency so that it looks like your natural enamel.
The result is a material that is durable, but not too durable, and practically indistinguishable from your natural teeth.