Zirconia replaces gold?
Zirconia can not replace gold! In fact, nothing replaces gold. If a patient bruxes and there is very little occlusal clearance, fabricate a gold restoration!!! Zirconia is a poor substitute for gold.
Some laboratories advertise their zirconia to be used instead of gold. In fact they are proud to say that their zirconia is the answer for that ugly yellow, high priced gold. They claim that zirconia can be fabricated very thin on the occlusal and still be super strong. That is a lie!
The fact is that zirconia and emax both need to be at least .8mm thick. That means your prep needs to remove .1 for cement spacer, .3 for clearance, .8 for material thickness (minimum, it may be thicker in other areas) leaving us at 1.2 mm of occlusal prep bare minimum. The walls, M,D.B.L. must all be 1.2 mm (minimum) thickness, thinning out to the correct gingival contour towards the margin. There can be no sharp edges around the occlusal edge. At .8mm you are still flirting with disaster, so always prep a little more instead of less.
How did this material grab such acclaim and popularity in such a relatively short time? The general public wants all natural looking teeth, as white as possible. It had to pass all the tests of a material that survives in the oral environment, (strength, hypo-allergenic, and others) as well as being a material that can be shaped or milled into the exact likeness of teeth. While avoiding the high price of gold, relatively. We begged until we got what we wanted.
That does bring up the question; If gold is the most superior material ever found to restore teeth with, but it is not a natural tooth color, and the price of gold is higher than usual, does that mean we have just traded the most superior material known to man for something cheap, and white (vanity). So our pocket books and vanity are dictating treatment? #cheapnvain