Hi, my kids have never had any cavities but today at their 6 month
cleaning, my daughter's new 12 yo molars (both on the bottom) came in with
cavities.  The dentist said her teeth are well taken care of and it was
nothing she did but they see this on occasion, for no reason, seemingly.
he said about 1% of kids have this.  My daughter has sealants on her other
molars.  He wants her back in soon for fillings and agreed to composite
rather than amalgam.  

A little background.  My son, who has no decay whatsoever, has autism.
Neither of the kids can tolerate flouride, mercury or thimerosal (actual
allergies as well), neither can have any dairy products but both get
1000mg/day of calcium (calcium citrate malate).  Her toothpaste contains
xylitol.  they both have white spots that migrate and come and go from all
of their teeth.  

I found nothing on Medline.  Any thoughts?  thanks in advance.