In some cases where you want to make sure you have coverage before a procedure is done. What a dental office or your self for that matter can do is to fill out a claim form stating it is a Quote only, and that work was not yet done but you want to make sure you stay with in your UCR rates. In fact some dental insurance plans will state that you have to submit claims as quotes for anything higher the 300.00. This is to help you stay with in the UCR rates. If you at that point still want the work done then you know you are paying for whatever the additional amount is.
In your case it seems as if the dental office did not list this procedure as a quote but as work in fact done. I would confirm with my insurance carrier just how it was filed to them. As a quote only or as a true claim. If they say it was showing as true claim then at that time it would be up to you to take action against the dental office. Also you can advise your insurance company not to pay any bills from this dental office with out confirming it from you first.
Either way you may want to go to a different dental office. So that they are not processing anything weather it is a claim, or a quote for one without you be fully inform of that fact.