infected root in tooth

I have a crowned tooth that is infected in the root. I am having troubles with sinuses. I went to the dentist and he wants me to get a root canal. Does anyone know what I can do instead? Maybe something that will get rid of the infection. He said the nerves are dead. I also have 2 crowned teeth that smell when I floss them. They smell like a sewer when I floss. Any suggestions on what I can do with all this bacteria going on in my mouth?

Thanks in advance.