The closely arranged, high-quality bristles remove up to 7 times more plaque than a manual toothbrush. The specially curved active tip also makes it easier to reach the teeth in the back of the mouth. Brush heads lose effectiveness after 3 months, but the smart brush head recognition reminds you beforehand. Your smart toothbrush tracks how often and how hard you brush your teeth and notifies you when it's time to replace the brush head. Don't own a Philips Sonicare smart toothbrush? Just keep an eye on the blue bristles. Once they turn white, it's time for a new brush head.