Dental floss is a special elastic nylon thread, specially designed to clean both sides of the teeth and gums deep in the crevices, these brushing toothbrush can not reach the place. When used to intercept a section of 40 to 50 cm long, both ends wrapped around the middle finger of both hands, taut between the two teeth, the lower teeth with the index finger, upper teeth with the thumb, pressed into the crevices of the teeth, the dental floss along one side of the teeth adjacent to the up and down to pull for cleaning, and then clean the other side of the teeth, repeat this action between each two teeth, and finally don’t forget to clean the last teeth adjacent to the surface.