How many days can I wait for my crown after permanent filling in RCT?

Hello

You should take care of that tooth because if you bite stronger food and you don’t enough dentin to support the tooth can get broken. So everything depend of that until you get a crown. 

My advise is to try to get your build up and crown asap, but if you need to wait for insurance to be effective just be extremely careful chewing on the side of the crown.  Crowns with CEREC technology can be done on the same day in just a couple of hours.

Hi:Depending on which tooth and the amount of tooth structure removed, you could possibly wait without directly chewing on the tooth to prevent fracture.  For more accurate answer, please post an xray of the root canaled tooth.Best,Dr. Maddahi

I would think that would be ok. Obviously getting the crown placed as soon as possible is best, but usually waiting a few months doesn't cause any harm. That being said, it wouldn't be impossible for that tooth to fracture within the next few months.