Hi, Your question has two different parts. One scenario is after doing RCT ( root Canal) and other aspect is after doing Composite filling. Regarding the Composite Filling, its ready to use as soon as it is done. Now the main thing is RCT. If your RCT was done in single sitting, there may be post obturation (root canal filling) pain and you might feel pain while eating from that side for some days. Even if your RCT was done in multiple sittings, there may be pain while chewing from that side which can last upto a week in some cases. All these differences vary according to the technique used, Root canal Filling material. So its better start chewing from that side 4-5 days after the Root Canal treatment.
Wisdom teeth rct
1) first of all wisdom teeth are most of time don't come in occlusion , so even if you try to eat with that side it will have no. Problem
2) you can even eat during rct , did your doc. Told you not to eat
3) composite is light sensitive as soon as doc. Done with giving light to composite its done , you can do anything