 An example of this are dinosaurs of the group Heterodontosauridae and the enigmatic early dinosaur, "Eoraptor".While most dinosaurs had a single row of teeth on each side of their jaws, others had dental batteries where teeth in the cheek region were fused together to form compound teeth.Individually these teeth were not suitable for grinding food, but when joined together with other teeth they would form a large surface area for the mechanical digestion of tough plant materials.