dental floss 
noun [mass noun]
A soft thread of floss silk or similar material used to clean between the teeth.It is very important if your gums are bleeding to clean them more thoroughly, not less, ensuring that you brush every surface of the tooth and clean in between the teeth with dental floss or interdental brushes....
- Use dental floss to clean between your teeth and remove any trapped food that could cause tooth decay.
- Interdental cleaning tools such as dental floss and interdental brushes can help you clean hard-to-reach areas of your teeth, such as between the teeth and under the gumline.