Can i have just 1 root taken out of a back tooth and how strong will it be. i've had loads of infections in just the one root and 3 root canals.

Hemisection: Yes, sometimes when one root is the culprit of many recurring infections, a removal of just the one root can be done. This is called a hemisection. An oral surgeon or endodontist should evaluate the long-0term prognosis of the tooth to see if this is an alternative for you.

You could, but: I am assuming you have had three root canal procedures performed on the same tooth that has the problematic root. Has the option of an apicoectomy been discussed or offered? You can have just one root removed (root amputation or a hemisection) performed, but with a history of three root canal procedures, is saving the tooth the best option or removal and consideration of an implant better?