The correct way to use dental floss. Step 1: Pull out a piece of floss about 25 centimeters long from the floss box, and wrap the ends of the floss around the first knuckle of the index finger of each hand 2 to 3 times, with a distance of about 5 centimeters between the two index fingers. Step 2: Straighten the floss by supporting it with your thumb or middle finger, and guide the floss to slide gently along the side of the tooth into the gap, while bringing out the food inclusions. Step 3: Place the floss against the neighboring surfaces of the teeth in a C-shape to increase the contact area, and then scrape gently up and down, side to side, to clean the surfaces and sides of the teeth, as well as the crevices deep in the gums. Step 4: After scraping the neighboring surfaces of one side of the tooth, scrape the other side of the same gap until the food inclusions, plaque and soft tartar in the gap are brought out with the movement of the floss. Step 5: Replace the floss with a clean one, and use the same method to scrape the neighboring surfaces of the teeth one by one, and rinse off the food residue, plaque and soft tartar. Note: The use of dental floss should be gentle, the beginning may not be too skilled, you can try a few times in front of the mirror, practice makes perfect, and gradually it will become an indispensable necessity in your life.