[KenoFischer]

Actually I think it's just a difference in definitions. You were looking at practicing dentists, while the number I quoted was licensed dentists. If I'm interpreting the numbers correctly, there are only 13088 dentists actually practicing dentistry (I don't speak polish, so I'm not sure if the difference is explained in the report). I'm also not sure how the world bank data is derived.

[KenoFischer]

And doing even more analysis, there were 87687 practicing doctors (not including dentists) in Poland in 2014, i.e. 2.3 per capita, which is close enough to that it could have been World Bank's data (which isn't available for 2014). Comparing those numbers to the US it just seems that Poland has a smaller dentist/doctor ration than the US.