Assistance with Whitney's Dental Bills

I love Whitney so much and I just want to help her out in any way I possibly can. 

First of all, why do dental procedures cost so much? Secondly, why do you have to wait a year after getting insurance to get some procedures done before they are even partially covered?

Whitney had a baby tooth left in her mouth that just never seemed to want to come out on its own. It got to a point this year that it needed to be extracted and the only way to fix it all was to put braces on after the extraction. 

Obviously this is an expensive endeavor and any other year we could manage it without assistance but of course it had to happen in 2020.

Any help would be much appreciated.