Who is eligible for getting dental worked financed at the dentist's office?

I'm likely going to need at least (by my estimate) $5000 worth of dental work done. I think my insurance would cover $1500 of it. My credit scores, if a factor, range from 650 to 690 - worst things showing on them is a paid collection from 2004 and a 30 day late CC payment from 2007. Is that likely to prevent me from getting financing on this? Would I be better of paying for TWO dental insurance plans? Can I even do that, and file two claims? The form I need to fill out for the dentist says "I agree to be responsible at the time of visit for all services provided." I honestly don't, and won't have that much money up front any time in the near future.
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Not available at the dental practices with the current financial crisis, you cant file two claims only one
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