Emax vs zirconia crowns?

Hi:Normally for grinders I recommend zirconium crown.  No matter which crown you go with you also need to wear a nightguard to protect your teeth against grinding pressure.Best,Dr. Maddahi

If you are looking for a great aesthetic result from restoring 18 teeth, I would definitely recommend Emax. They are very strong once bonded, and will give you the transparency that natural teeth present. Zirconia can be a great option for posterior, or back teeth, but they will appear dull and opaque, giving you less of a natural-appearing result for your smile. There are different shades of cement your dentist can use to "block out" the yellow tone of your natural teeth so that the crowns/veneers won't appear as dark. As for your grinding, I would suggest you get a nightguard to protect your teeth and jaw, regardless of which material you end up choosing. Botox injected into your jaw muscles is also a great option to weaken the muscles so that you are no longer able to grind your teeth. 

I tend to place eMax over Zirconia in all situations. In addition to being more esthetic and stronger, I find that eMax bonds to the teeth much better!  Zirconia crowns don't adhere to your tooth as well, and can become loose needing to be re-cemented.I don't think your deep yellow stains will show thru the eMax crowns if they are blocked out properly.  Regardless, I would leave it up to your dentist as there may be more factors he's considering while opting to place Zirconia on the back teeth.

I recommend zirconia is grinders for it's strength. But Emax is more esthetic and can be bonded to the teeth decreasing the chance of it coming off. As far as translucency, either option should be able to mask the discoloration of your natural teeth. 

Can't go wrong with Emax in your case.  The material is very strong and will hold up with your bruxism habit.  In addition, the material can be layered to give a highly esthetic look.  Important to decide on a color that you want with your veneers first though and relay that to the dentist so the final result meets your expectation.  With your 'yellow' starting color, the dentist will have to account for the change of color necessary by altering his preparation depth as needed at the time of treatment.