Preheat oven to broil.
In a small bowl, combine melted butter, oregano, garlic powder and salt. Set aside.
Arrange the bottom halves of the slider buns on a foil-lined 9-inch x 13-inch baking dish or sheet pan. Brush with half the butter mixture and broil until toasted, watching closely to prevent burning, about 2 minutes. Reduce oven to 350°F.
Divide turkey evenly on top, followed by marinara, mozzarella and 1 cup of parmesan. Replace top halves of rolls. Brush tops with remaining melted butter mixture and sprinkle with remaining ¼ cup parmesan. Bake for 20-25 minutes, or until tops are golden brown and cheese is melted.