I was over in Jan getting some work done. A crown and about 10 fillings... my girlfriend is from Krakow so know her way around. We went to this dentist and he was great. Very professional, really nice guy and reasonable prices. Also make sure to get your tax forms filled out as you can claim against that for work anywhere in the EU.
http://www.twoj-dentysta.med.pl/en/index.html
Email:
t.rozwadowski@twoj-dentysta.med.pl
I got a porcelain crown as it was one of my front teeth and it took around three one hour appointments for that.
Darragh.
P.s. Book in advance if you only going for a week...
P.p.s. Ask for Thom, the nurses don't speak English, it's only the dentist that does.