i was going to post the same suggestion.
my son is 3 1/2, about a year ago he had many cavities, about 6 i think, only one we had filled and the others took a wait and see approach. I started cod liver oil and butter with him and really cracked down on his diet, and now a year later, i dont see any brown spots left(they were all visible) and latest check dentist said only one small cavity too small to fill(tiny teeth!)
I had a filling fall out, and havent had it replaced, in this past year i also began the cod liver oil butter combo, and the area looks much more like a healthy tooth now, not like a tooth with holes all over it. I have yet to find out if it is doing the trick, but i think it is.
the oil pulling has helped all gum inflammation and discomfort in my receding area go away, but unfortuately i havent been consistent with it enough to see results beyond that, hope to get back on that soon as the results were fast and dramatic for my gums!
if you go the cod live oil route, be sure to carefully choose, so as not to injest metals and the what not. i use carlson, and the lemon flavor one is really great, almost no detectable fishiness!
good luck