I am currently in chemotherapy. I am trying to give my body as much help as I can to stay strong and to heal. For example, studies have shown that oral health is very much connected to overall health. I have some teeth with cavities that have been filled to keep them viable, but the fillings are there because I haven't been able to afford crowns and are a stopgap measure. They should have crowns on them before they get to the point of needing to be extracted or having root canals. I do not think it would be a good thing to have root canals while undergoing chemotherapy treatment. The chemotherapy is enough stress on my body as it is. I also have several teeth that already have had root canals. One of them is decades old: a front tooth. Another had a crack that went into the root before a root canal was done. It probably should be extracted. I am missing an upper right first molar and the tooth that had the crack in the root is the same tooth on the left side: the upper left first molar. If I had the tooth on the left removed, I could then get some sort of bridge or flipper to make it easier to chew. If anyone is able to help, I would be most grateful for your kindness.