“What's the difference between porcelain and zirconia crowns?”

They are 2 different materials widely used in dentistry. They both have indications and when used in treatments they are indicated, they last for a long time. 

These are two different materials and used in different situations. First off they are both tooth colored materials and there are different variations of each material. Zirconia is a much harder material then the strongest porcelain on the market. Porcelain acts much more like tooth structure and can be bonded to the tooth leading to potentially more conservative restorative work.
You would have to have your personal situation to see what material would be right for you. You are more then welcome to call the office for a complimentary consultation to talk over your options.

There are many different kinds of both porcelain and zirconia used to make dental crowns. The primary difference is the aesthetics and strength. In GENERAL porcelain can be used to make much more aesthetic and natural looking dental crowns. Zirconia is getting more aesthetic usually as the strength is compromised. Zirconia can be the strongest material used to manufacture a dental crown. All this said the expertise of the dentists and the laboratory used will have the most effect on the aesthetics.

The porcelain is fired and the Zirconium is pressed.