Less mess suction cup. 1 min. ADA Accepted: American Dental Association. Firefly toothbrushes are fun to use and help create good oral care habits at an early age. Our Firefly Ready Go Brush flashes for at least 60 seconds, the dentist recommended time for proper cleaning of each row of teeth. To encourage brushing, the green light flashes for 5 seconds so you know when to change rows. Brush twice per day. Batteries included. When light no longer flashes, it is time to change your brush (approx 3 months).