There has been a recent study in Germany and the puzzling thing is that ALL tested dummies tested positive for BPA. Even the ones that were Polycarbonate free and shouldn't have any BPA in them. They didn't quite know why that was but it is worth mentioning that the ones with shields that were made out of other materials than polycarbonate had only very minute amounts of BPA. One theory was migration of BPA from packaging into the dummy.
Anyway, the dummies tested with the lowest BPA values were MAM dummies. NUK was second lowest.
It is usually not the teat that is the problem as both latex and silicone are BPA free. It is the shields you need to worry about.
If you are really worried, you could try one of the all latex dummies like the Natursutten which is available online. Guaranteed no BPA or phthalates.

Hope that helps.