What if the braces don't work?

I have an under bite and my orthodontist told me I should get the jaw surgery to correct my bite. I refused the surgery and said that I would be willing to remove teeth to straighten out my teeth. He said earlier in the treatment that there was a slim chance that braces alone would work. Now I need to get two front premolar teeth extracted to try to correct my bite. I was wondering if I got these two removed and the treatment didn't work, what would happen to the extraction gaps? Would he just leave them?