I think any toothpaste containng sodium flouride is poison. I used to do the flouride thing because the dentists told me so, now I feel so stupid for believing them. I have lots of fillings and my children do as well. When we stopped injesting poisonous water and using poisonous toothpaste, all of our teeth started looking so much better. Good thing I realized it before my children got any permanent teeth.
I've recently been doing some detoxification on myself. Though I don't usually get cold sores, I did get a whole bunch in my mouth for a week or so. I used the Dr. Schultze's tooth and gum formula and oil swishing, and it cleared them up in 2 days.
Supposedly, a lot of cold sores may mean your saliva is overly acidic. This could be because you don't eat properly, or you used to eat improperly and now your body is trying to get rid of all the toxins. You may want to visit the various acid/alkaline forums.