At 16 months I finally retired my baby toothbrush (my wife got me one with a teddy bear on it) and went back to the Sonicare.

One week does seem a little early for these kinds of problems however. I don't recall ever having gum bleeding even during the worst phase.

I got "longer in the tooth" as a result of some gum loss but they held up pretty well. IMRT is the least of the evils for harshness on the gums. More surprising is that it's in your front teeth - typically the teeth most exposed to the radiation take the brunt such as the molars. I would get to a dentist or dental oncologist and have it checked out.

By your comment that your dental health is good I take it that you are free of gum disease as well?

If you are not flossing carefully you can easily cut the gums as well. I used a Waterpik during the worst part of treatment.

I wouldn't plan on loosing any teeth - I still have ALL of mine - I wouldn't let them pull any out.

You must be willing to go the distance however, dental trays, flouride treatments, frequent cleanings, floss, WaterPiks, etc.