The Cardassian Bureau of Identification was a government agency that collected personal information on all inhabitants of the Cardassian Union.
All Cardassians were required to give the Bureau their first molar. This usually occurred at age ten. Non-Cardassian persons taken into custody for crimes within Cardassian space were also compelled to have a molar removed. This happened to Miles O'Brien when he was arrested by Cardassian authorities in 2370. (DS9: "Tribunal")