Dual-length bristles surround and reach deep in-between teeth , Higher density of bristles for an ultimate clean , Unique round brush head with gentle micro-vibrations . The Oral-B iO Series combines powerful, but gentle micro-vibrations with Oral-B's unique dentist-inspired round brush head design for a professional clean feeling every day. Ultimate Clean Refills help remove plaque, leaving teeth feeling clean and bright every time. Tufted, dual-length bristles surround and reach deep between teeth to help better clean hard-to-reach areas of the mouth. The round shape of Oral-B brush heads is designed to mimic the dental professional tools used for tooth-by-tooth cleaning. Dentists recommend changing your toothbrush head every 3 months for best results.  Includes 6 replacement brush heads, compatible with all Oral-B iO rechargeable toothbrushes. Built In Brush Head Reminders For an Effortless Clean Sync your iO handle with the Oral-B app to track your brush head usage. The interactive display on your handle lets you know when it’s time to swap.  #1 DENTIST RECOMMENDED BRAND WORLDWIDE Discover the next level of oral care innovation, brought to you by Oral-B, a worldwide leader in toothbrushes. Each Oral-B electric toothbrush provides a superior clean vs. a regular manual toothbrush. Find your perfect electric toothbrush from Oral-B which is the #1 dentist used and recommended brand worldwide*. *based on surveys of a representative worldwide sample of dentists carried out for P&G regularly.