 Small ridges, or denticles, lined the edges of ornithischian cheek teeth in order to crop vegetation.These denticles extend only a third of the way down the tooth crown from the tip in all heterodontosaurids; in other ornithischians, the denticles extend further down towards the root.Basal forms like "Abrictosaurus" had cheek teeth in both maxilla and dentary that were generally similar to other ornithischians