Hi all, just for your information: Radiation is a localized treatment, whereas Chemotherapy is systemic. If you are having radiation to your head and neck area, your teeth may be affected, but radiation for breast cancer wouldn’t cause problems with your teeth. However, it is taxing for the body to go through the repair cycles that happen with radiation, so an existing issue might become more severe because your body is working hard to repair the area that was affected by cancer. That is why fatigue is the most common side effect from radiation. It is more likely that side effects from chemo may be causing problems in areas away from the cancer site or that the issue with your teeth is completely separate from either of those treatments.