yes this is the same tooth which i spoke about previously. But you can see this is a terrible dilemma for me.

I dont want to replace the gap if i extract it because that will involve a fair amount work and will likely be more expensive that the root canal. However as you mention the root canal uses harsh chemicals which is unacceptable to me.

How much of a shift will occur if the gap is left? my teeth are already not perfectly straight so would it matter much?

can the amount of shift be accurately guessed or is it impossible to say?