A downhole cutting tool includes a body having a central axis extending therethrough, a plurality of blades extending outwardly from the body and converging towards a central region around the central axis, and at least one cutting element having a longitudinal axis, a non-cylindrical substrate, and an ultra-hard material body on the non-cylindrical substrate, the ultra-hard material body having a side surface extending around a cutting face and defining a cross-sectional shape of the ultra-hard material body, and the side surface comprising an edge having an inner angle of less than 180 degrees.