Can a dental office submit claims to insurance LATER?

I went to my dentist yeaterday. I supposed to have dental insurance trough my wife's work (actually we paid for it), and HR ar her work told her that the insurance will kick in Nov 01/2007. Yes, but when I went to the office they checked with the insurance company and said to me that there is no insurance under our name. When my wife double checked with Human Resources they told her that the insurance actually will kick in Dec 01/2007 (one month later). I didn't pay the bill. The dentist said to me to clarify the problem and call them bak. I am going to call the office tomorrow. Is it possible for them to claim the work they did after Dec 01/2007 or I have to pay cash AGAIN. It is so painful paying cash and insurance at the same time, isn't it?
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They can pretend that you got the work done on Dec. 7 instead of Nov. 7, but its technically insurance fraud. however, if they are willing to do it, let them do it.
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