Philips Sonicare Premium HX9044 / 17 spare heads 4 pcsPhilips Sonicare C3 Brushheads Premium Plaque Defense offer superior plaque removal results. The heads must be replaced at prescribed intervals , both to maintain full functionality and for hygienic reasons. Ideally, replace the warhead every three months. You will also be reminded of the need to replace the special blue fibers, which turn white when worn too much. The heads offer up to four times greater contact with the surface of the teeth and