Oral-B Essential Floss Cavity Defense helps remove plaque to reduce cavities. Cleans where your brush can't reach. Wax coating and shred resistant. Instructions: Wind 18 in. (or 45 cm.) of Essential Floss dental floss around middle fingers. Gently slide floss between teeth and under the gumline. Use an up-and-down motion to remove plaque and debris. Repeat between all teeth contacts, advancing floss to a clean section each time.