Experience the Magic of Oral-B iO Technology Say goodbye to guesswork and get back to 100% Cleaner Teeth with Oral-B’s unique dentist-inspired round brush head! With iO refill technology, your brush head knows when it's time for a change. Watch the magic unfold as the color transforms from vibrant blue to pristine white, signaling when it's time to change and ensuring a fresh and effective clean every single time. The iO collection is Oral-B’s best technology. Oral-B's Best Technology for Gentle Care These replacement brush heads contain High Density Dentist-inspired extra soft bristles for a gentle but effective clean.