Zirconia is a very strong ceramic that we use now for crowns.
The crown in the 1st photo is the older type of “metal-ceramic” which shows a grey margin after a few years.
The Zirconia crown which we replaced it with (2nd photo) is completely metal-free, extremely durable, and looks far more natural.
![](https://content.ibizify.net/uploads/31c932a2-4bf6-4dee-a143-550bae3315a2.jpg)