Dental Assistant training is different for each state.
It is best to look for your states medical board and click on Dentistry.
The pay depends on the state in states that do not require a certification or specialized training ie an Associates Degree, the pay is significantly less.
My friend is a DA and made 22.00 p/h in NC, but now in GA only makes 14.00 p/h ( and she has 10 years of experience).
Hope this helps.