Biological Dentist ...

In NL (I did a search because I didn't have a clue what a "biological dentist was!)

Netherlands - Directory of holistic / bio-compatible / mercury-free dentists

Amsterdam

Erik van Leeuwen
Lisdoddelaan 15, Amsterdam, - 1087 KB.
Phone 011 321 20 668 5991.

Amstelveen
Rene van der Bijl
Dubbelmondehof 33, Amsterdam, - 1069 ZA.
Phone 011 31020 445 9936 or 6102883.

Apeldoorn

Apeldoorn
R. A. Muts
MP3 Tandartsen, 7301 GH Apeldoorn, - 10325.
Phone 155 355 3153.

Like Luke above, I've no idea what a biological dentist is but I checked out Yellow Pages and got the following 2 options:
http://www.goldenpages.be/qn/business/advanced/what/biological%20dentist/