Contrary to the belief of some, it is possible for cavities to form under dental fillings! Although
dental fillings are designed to seal your tooth and protect your teeth, no dental filling material
lasts forever. Whether you have silver amalgam fillings or composite resin ones, your filling will
need to be replaced at some point.
So why would a cavity form under your dental filling? Here’s how decay can creep in under your
filling and cause a new cavity.
The Filling Has Been Damaged
If your filling sustains any type of damage, whether it’s from everyday wear and tear or you
accidentally injure it, you open up your vulnerable tooth to bacteria that can cause a new cavity
to form underneath your filling.
Such activities that can damage fillings may include grinding your teeth, chewing on ice, or
chewing on hard, sticky foods, such as candy. A damaged filling needs speedy repair by your
dentist; although unfortunately, some people don’t know that their filling has been damaged,
which is why regular checkups are so important!
Your Dental Filling Is Dated
Filling materials can become damaged over time or worn out. Your filling does have a life
expectancy depending on its material. For example, silver amalgam fillings have a life
expectancy of 10-15 years while composite resin fillings have a lifespan of 5-7 years.
Fillings experience everyday wear from your regular mouth functions of biting and chewing.
This wear and tear can cause the seal that binds your dental filling to your tooth to wear down,
which can cause bacteria to slip underneath the filling and begin damaging the tooth again.
In addition, for some patients, the seal is not initially created properly, which can lead to a
shortened lifespan of the filling and the need for early replacement.
Your Filling Is Too Large
If your cavity was a large one and there wasn’t enough existing tooth structure to properly
support the filling, your filling may be faulty and allow for decay to begin forming again
underneath. Typically, fillings like these will instead require a dental crown.
If your dentist attempted to fill your cavity to protect the tooth when there should have been a
crown, you may be more at risk for the filling to allow decay to form—or your filling may simply
fall out—and you’ll need to get a dental crown at some point.
Are you concerned that a new cavity may be forming under your dental fillings? The best way to
determine the health of your dental fillings is to visit your dentist for an exam. These fillings are
best evaluated by a professional, and your dentist can tell you if your fillings are in good shape,
if they need repair, or if you have decay underneath. Getting your fillings examined can help
prevent cavities from forming underneath!