Thank you for your reply telling me about the cardboard X-film holders putting stress on my jaw during the dental X-rays. I did feel a lot of discomfort at the time when the X-rays were being taken. It makes a lot of sense that the procedure could cause a migraine to flare up.
On another subject, Magnesium for help preventing Migraines, I wonder if anyone has ever tried Magnesium tablets before bedtime to help prevent a migraine from coming on during sleep. I have been told that taking 300-400 mgs before going to sleep can help prevent a migraine from starting. Has anyone else ever heard about this and if it could possibly give some relief from waking up in the middle of the night or early morning with a terrible migraine?