Preheat oven to 350F.

In a large bowl, combine sour cream, 4 tablespoons of the cheese, Dijon mustard, oregano and black pepper. Fold in artichokes, spinach and basil. Transfer mixture to a shallow baking dish and smooth the surface with a spatula or the back of a spoon. Sprinkle with bread crumbs and remaining 2 tablespoons of cheese. Bake 20 minutes, until top is golden brown. Serve with pita wedges.