A dental crown made from Zirconium Dioxide ($ZrO_2$), a white crystalline oxide of zirconium. It is classed as a metal-free ceramic but has the strength of metal.
It is virtually unbreakable. Unlike porcelain (which can crack) or metal (which looks ugly), Zirconium offers the perfect balance. It is biocompatible and does not cause gum irritation.
Typically 15–20 years or longer.
Yes, they are the strongest tooth-colored material available in dentistry.
No. The material is non-porous and highly resistant to coffee, tea, and smoke stains.