Generally artificial teeth/crown are made of two layer's inner one is metal and the outer one is ceramic i. E tooth colour. With time and use of the crown the outer layer i. E. The tooth coloured layer of the crown wears out or gets chipped off due to the continuous pressure on the crown.
You can get a new crown for your teeth or else if it isn't creating any problem then you can continue with the crown.
But do visit the dentist
as by looking at it only a more precised solution can be given to you.