The Philips Sonicare Optimal plaque Control brush head features a concave trim profile specifically designed to target tooth-decaying plaque by hugging teeth and offering better conformity and surface-area coverage. Compatible with all click-on Sonicate models, these replacement brush heads remove up to 7x more plaque than a manual toothbrush. Use with a Philips Sonicate brush Sync(TM) compatible handle (Diamond Clean Smart or protective Clean) to unlock Smart features: brush Sync mode-pairing triggers your handle to select optimal mode and intensity level for exceptional plaque removal (certain models only); brush Sync replacement technology tracks how often and how hard you brush and will notify you when it is time to replace your brush head.essential oil Warning: toothpaste containing essential oils can damage your brush head. Avoid direct contact with products that contain essential oils or coconut oil. Use may result in bristle tufts dislodging.reminder bristles fade to let you know when it's time for replacement. Replace your brush head every 3 months as recommended by the American Dental Association. A fresh brush head every 3 months maximizes the effectiveness of Philips? unique sonic are technology.Philips sonic are optimal plaque toothbrush heads were formerly sonic are Pro results plaque Control. Brush head not well placed Reattach the brush head. Make sure that the brush head is well placed and not loose or wobbly. A small gap between the handle and the brush head is normal. Counterfeit brush heads Counterfeit brush heads may make more noise than genuine Philips Sonicare brush heads. We recommend you to use genuine Philips Sonicare brush heads. Brush head is worn If you used the same brush head for more than three months, you might need to replace your brush head. As brush heads wear out, they may start to produce more noise. We recommend replacing the brush head every three months.