Should I get root c now?

Recently a tooth in my upper left side had been aching. I went to my dentist, he saw "nothing," on an x-ray. He referred me to an endodontist. This guy is very good, and through a microscope he found a microscopic crack in my tooth. He says I need a root c, but my tooth hasn't hurt in over two weeks and I'm due to get the root c next Monday. I keep hearing "You could lose the tooth if you don't get the root c." Just wondering can I/should I just wait?