Do you know of a good dental insurance that covers braces?

I need a dental insurance that covers getting braces (in a adult not child). Do you know of one?
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Lots of dental insurances cover orthodontia, most, however, have a lifetime maximum of usually about 2000.00. Private insuraance is expensive, and doesn't usually have a high routine maximum, and no coverage for orthodontia. This is for Canada. Not sure about the US.
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