Any crown given after rct helps in restoring the chewing ability of the that tooth.
The various options available would be:
1) metal crown
Adv: most economic
Disadv: not very esthetic/ not tooth colored.
2) pfm ( ceramic with metal)
Adv: tooth colored
Disadv: the metal layer inside may discolour gums over a period of time.
3) zirconia (all ceramic without metal)
Adv: most esthetic/ very close to natural tooth
-No gum discoloration with long term use
Disadv: expensive compared to others
Crowns have to be chosen based on the rehabilitation required. Primarily it is the function that is chewing, then esthetics and last is the price. please ask you dentist based on these requirements and will be easy for both of you to choose.