GUM Eel-Thru floss is coated with a non-stick surface so that it easily slides between tightly spaced teeth and below the gum line to reach the dental plaque. If dental plaque is not removed frequently it can cause inflammation of the gums and lead to gum disease. GUM Eel-Thru is a monofilament made from PTFE, the common non-stick material that creates a satin-like finish that is extremely soft and gentle and also shred-resistant.