dental decks 2006 have almost all the questions from the 2004 series in them as well as the new additions mentioned above. i think DD 01 are not very different from 04. so 2006 is a must-have. but i feel that the illustrations section in 2006 DD is not very helpful. i had to open the books to look for illustrations for a better understanding. tho the clinical vigenettes are very helpful. they have also covered a whole lot more topics in the 2006 decks. i hope this helps. good luck!