The Oral-B FlossAction Xfilaments replacement brush heads provide a floss-like clean for healthier gums.**does not replace flossing. Designed with unique FlossAction bristles to loosen plaque, the dentist-inspired round brush head has specially engineered bristles for a complete clean. Max Clean Bristles indicate it's time to change your brush head. Make sure to always clean the brush head thoroughly after use. Oral-B—the #1 brand used by dentists worldwide.* *Based on surveys of a representative worldwide sample of dentists carried out for P&G regularly. Oral-B recommends brushing with Crest Toothpaste for optimal results. Do not use on children under age 3. Replace brush head every 3 months or sooner if brush head becomes worn.