Need some advise. I have toothache recently and it was the one that I did filling last year. The filling is near to the nerves and now it is infected and giving me toothache.

My dentist told me my molar (16) is "dead" now and need to do RCT. However this tooth is behind my other tooth (double layer of teeth i have). And I am thinking should I just extract it and go for braces (since dr said my teeth will be shifted if i removed the 16) or go for RCT?

Problem is RCT doesnt guarantee the pain wont come back.
What is the impact in the future if i dont extract and go for RCT? Will the bacteria cause some other disease (im not sure if it is really bacteria related)?