A few misconceptions of flossing lie in our lack of understanding to its purpose. The goal of flossing your teeth is not to get visible food particles out, while it is a bonus it is not the end goal. Biofilm is a collection of bacteria that forms on surfaces where they continue to grow unless disrupted. The plaque on your teeth is actually a biofilm, the bacteria in your mouth has been allowed to rest long enough to form a colony of various species and can now begin metabolizing your teeth.
Flossing disrupts the biofilm in a way that brushing your teeth or using mouthwash cannot. It is essentially poking an ant hill; the ants will be more focused on rebuilding their habitat than on hunting down the piece of fruit you left on the counter. Instead of eating away at your enamel the bacteria must reform its community. The time period for when plaque is reestablished is hard to estimate, however, flossing before bed is your best bet to prevent the film from being able to reorganize. For tips on how to floss you can visit Mouth Healthy from the American Dental Association. And for more information about flossing and methods of cleaning you can visit the American Dental Association website.
Below is also a video on how to floss your teeth with visual reasons to want to do so.