The contact is just
too tight. If this is the case your dentist can lighten up the contact for you
with a minor procedure. Actually taking a sand paper or metal strip between
the teeth and removing some filling material. You want a tight contact so you
don’t get food caught, but you also want to be able to floss. There are
special flosses on the market that can be helpful for tight contacts, ask your
dentist.

       The floss is getting
caught on a rough, overextended or broken portion of an existing filling. If
this is the case your dentist may suggest that the old filling be replaced
with a new one. It may be the same type of filling or it may require the
filling be a casting, such as a gold inlay or a crown. This is necessary
because the portion that is catching your floss is also catching plaque and
bacteria. This plaque can lead to gingivitis or perhaps gum disease if not
treated. Once treated the floss should pass through without shredding.

       The floss is shredding
because there is a sharp surface around an area of decay between your teeth.
Your dentist can x-ray this area and determine the amount of destruction
present. Then you and your dentist can determine the appropriate course of
action. Whether it be a silver filling, a gold filling, or a crown the decay
must be removed and a restoration placed.