Only 3 out of 5 tooth surfaces can be adequately cleaned with a toothbrush.
Dental floss must be used to clean the others. You should floss at least once a day- preferably before going to bed. Cut off a piece of dental floss about one feet long. Wrap one end around the right index finger for holding or anchoring. Use the right thumb to hold the floss against the right index finger. Grasp the other end of the floss on the left hand so that a one inch length is between the hands. Slip the floss between each pair of teeth by drawing it
gently and slightly back and forth. Carry the floss under the gum until you feel definite resistance without discomfort, completely hugging the side of that tooth that you're working and then do the up and down motion scraping it along the sides of both teeth.