Place an oven rack in the centre of the oven and preheat to 230°C/gas mark 8.
Cut each pita half into 4 wedges. Arrange the pitta wedges in a single layer on a baking sheet. Brush with the oil, then sprinkle with the oregano, salt and pepper. Bake for 5-8 minutes until crisp and golden.
In a medium bowl, combine the bacon, mascarpone cheese, sour cream, and chives. Season with salt and pepper, to taste. Transfer the dip to a serving bowl.
Arrange the pita chips and dip on a platter and serve.