Did you know that bacteria thrive on a toothbrush after use? In a warm, moist environment of an average bathroom, bacteria on your toothbrush can double every 20 minutes resulting in as many as 100 million microorganisms on your toothbrush! The Mouth Watchers innovative antimicrobial bristles eliminate 99.9% of bacteria build up on the toothbrush bristles. Made from advanced PBT (polyester) plastics, these bristles outlast less expensive nylon bristles found on competitive toothbrushes. You can also choose the bristles in either soft or hard variants--soft dental floss bristles for cleaning between teeth and in hard to reach locations; thicker, harder inner bristles to ensure complete cleaning.