No dental floss does not stretch.
You must dental floss because if you don't plaque will grow off the food in your mouth.
Actually, currently biodegradable dental floss in market, only silk and PLA floss can reach 100% biodegradable.
yes, you can.
You can buy refill dental floss for your Glide dental floss tool at most grocery stores. If it has handles and prongs at the top, this is where the refill goes. You can also check big box stores.
Dental floss is a string kind of thing (hard to explain) which you put in between your teeth and go up and down, as a result any plaque between the teeth will be removed.WARNING:Do not swallow the dental floss.
Floss holder and dental floss sticks come in either a "knife" shape or a "Y"shape.
That is equal to the bacteria on your toothbrush, it depends on how often you get a new one. But dental floss is usually cut and tossed away after use, so I´d say the leftover floss is pretty clean. In any ways, if you do not soak the floss in a bacteria-infested liquid, it´s not dangerous to your health at all.