The triggered ability of Dennick, Pious Apparition looks at what type the cards are after they move to the graveyard to determine whether the ability should trigger, regardless of any types they may have had before they were in the graveyard. For example, a creature card that has become a noncreature permanent, perhaps because it was enchanted by Minimus Containment, will cause the ability to trigger when it's put into a graveyard. By contrast, a noncreature card that has become a creature on the battlefield will not cause the ability to trigger when it's put into a graveyard.