Oregon

File a complain with Board of Dentistry. 

https://www.oregon.gov/dentistry/Pages/complaint.aspx

File a complain with Oregon Department of Justice consumer protection 

https://www.doj.state.or.us/consumer-protection/

I think board of dentistry is more applicable because they would know what is a proper price to charge in your situation.  Consumer protection is more about fraud and lemon.