I used to get the same type of headaches when I had my braces. They were worse after my ortho appointments, probably because they tightened the braces. The only thing that ever worked for me was an OTC pain killer (Tylenol or Ibuprofen) and rest.
Make sure that she's drinking LOTS of water. I get bad migraines and most of the time it's due to the fact that I'm dehydrated. For some reason, it took my doctors years (and a few hospital visits) to make the correlation. The last time I went to the hospital, they told me I was severely dehydrated. Up her water intake and see if that helps.
Other than that, I would do some research on different types of headaches and maybe consult a headache center.