Contains nano-hydroxyapatite, refillable dental floss David's Premium Dental Floss impregnates the fibers with nanohydroxyapatite, which aids in remineralization between teeth that are difficult to reach with regular brushing, making them less prone to tooth decay. Also whitening effect. Original natural mint oil with a clean and fresh scent. Reusable cases (dispensers) and refills (refills) reduce waste in single-use cases (dispensers). The floss is made of polyester fibers made from recycled PET bottles. While maintaining the good feeling of using plastic fibers, we have adopted environmentally friendly materials.