opinion on dental procedure?

I'm getting braces pretty soon, but I have some cavities. Should I take care of the cavities first, and then get the extractions done? I'm afraid that if I get the cavities done first and later, I find out that I have to get one of the tooth extracted, it'll be a waste of money. What's should I do?
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The teeth usually extracted for Ortho purposes are the first Premolars. Have your cavities filled first and the Doctor will know not to fill the cavities (if any) in the first premolars. Just explain to him the situation.
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