If you have to have dental x-ray done, load up on some methylene blue, niacinamide, caffeine and aspirin about an 1 hour before the x-ray. Then, after the x-ray is done take the above mixture for 3 days. This should take care of the most damaging part of the immediate and post-exposure x-ray effects.
Btw, this recommendation would apply for any x-ray anywhere in the body. If you are getting a CT scan, which is essentially an x-ray on steroids, I would up take the combo for at least a week after the CT scan.
The dosage of each ingredient individually shown to provide some protection is 15mg methylene blue, 1,000mg niacinamide, 1,000mg aspirin, and 400mg caffeine.
@haidut - Do you have any updates to this protocol? I think I have to get a cone-beam CT of my skull in the next few months and want to minimize/negate the damage.