1. Wrap one end around the second finger of the middle finger and save two turns, and then wrap it around the second knuckle of the middle finger of the other hand at a distance of about 20 centimeters. 2, the fingertips of a clenched fist, you can put the dental floss taut. 3, turn over both hands, so that the palm outward, while straightening the thumb and forefinger of both hands, so that they have been angular quadrilateral, while the thumb gently contact and parallel with the dental floss, which is the dental floss in the two middle fingers between the appropriate length, but also this is the operation of the basic gestures of the dental floss. 4, floss over the index finger of one hand and the other thumb head of the meaty place. Keep the floss 1 centimeter long between the two fingers. 5, two fingers straight, fingernail to fingernail, the floss into the gap 6, the floss taut teeth adjacent to the surface so that it is slightly C-shaped up and down scraping, two fingers at the same time up and down movement. 7, scrape the other side of the same tooth. 8, the same way, clean the second gap between the adjacent surfaces of the teeth. 9, scrape the adjacent surface of the lower row of incisors, the index finger to change from the top to the bottom position, at this time the essentials for the index finger arm to be raised. 10, index finger inside, thumb outside, while moving up and down. 11.When scraping the back teeth area, use the index fingers of both hands. 12, one hand index finger will be the corner of the mouth and cheeks slightly open. 13, Starting from the canine teeth, clean the teeth one by one. 14. Move the index fingers of both hands up and down at the same time. 15, can first scrape the upper jaw back teeth area, at this time the head can be tilted back to facilitate the line of sight. 16, scrape the lower jaw of the back teeth area, is the same way, at this time to close the jaw, in order to facilitate the line of sight. 17, to do until the last face of the last tooth. 18, it is appropriate to start from the easier front teeth, gradually to the back teeth. When you are familiar with it, you can start from the upper right back teeth and clean each gap in turn.