SAN DING automatic expansion of dental floss, and full of expansive use of xylitol in contact with water that is the special fiber material, the surface covered with a layer of natural food wax, is a production through modern technology and disinfection of the new oral hygiene products. Clinical evidence that dental floss with saliva in the mouth after contact with the natural expansion of the formation of many small pores with a reticulate-like soft fibers. Not easy to fork, break, can fill the gap and does not cause tooth gum discomfort, which can effectively package the food residue and bacteria absorbed and removed. Daily, can prevent the formation of periodontal disease.