Qualifications For Dental Hygienist To Work In An Orthodontic Office?

Does anyone know if you need more schooling to be a dental hygienist for an orthodontic doctor? Do they get paid better in orthodontics than they do in normal dentistry?

Lack Of Dental Hygienist Benefits?

I am starting to take the steps to educate myself to become a dental hygienist. As I was reading some answers to various DH posts I noticed one that mentioned the lack of benefits dent. hyg. have. For the most part I am so intrigued by the field of dentistry and orthodontics as I have had this feeling for years but it did make me think for a split second. They mentioned not having sick time, insurance, retirement, etc..to have a good support system if kids are sick..I mean right now that doesn’t worry me so much as I am in my 20s and don’t have kids. I wonder does it just depend on the dentist you find to work for? Seems that was the only post I saw mention it..
On a side note- I love orthodontics! Are dental hygienists trained to be able to work in those specialty offices or is it only dental offices? Do most orthos only hire dental assistants and not hygienists?
Thanks :) )