Protecting Our Kids' Smiles

Unless you have an old-style amalgam (metal) dental filling, you would expect your restoration to be the same colour as your tooth. Contemporary fillings are typically made of a composite dental resin, and your dentist goes to some effort to make sure that the filling is the same colour as the tooth that hosts it. This makes your filling, for all intents and purposes, invisible to the casual observer. Until it's not, that is. Why does it seem like your composite dental resin filling is becoming darker?

Into and Across the Cavity

When applied to a cavity, the composite resin expands down into the depths of the cavity, while also covering its entire exposed surface area, overlapping with the natural dental enamel that surrounds the cavity. This overlapping effect creates a strong seal. The seal is intended to be permanent, but this idea of permanence is limited to the life of the filling—and dental fillings aren't immortal. 

Broken Seal

Natural wear and tear can cause micro-movements of the composite resin within the cavity. The filling isn't in danger of falling out (although this might happen without further action), but the filling's seal with its tooth has been broken. This allows seepage into the tooth. Oral bacteria, microscopic particles of food, and other contaminants can enter the tooth and accumulate around the edges of the filling, creating a dark line.

See Your Dentist

In addition to the dark line around the edge of the filling's broken seal, contaminants may be pooling beneath the filling, causing its discolouration. These changes to the appearance of your filling mean you'll need to see your dentist. The filling will need to be replaced before it fails entirely, which will accelerate the deterioration of your tooth. Failure to act means that you may need a dental crown instead of a replacement filling. If the cavity is permitted to deepen, the tooth's nerve may become infected, and you might need a root canal. Your darkened filling isn't a dental emergency just yet, but acting quickly will be in your best interests. 

Staining

Alternatively, a composite resin filling can stain, which causes it to darken. This may be a combination of diet (consuming foods and drinks with high levels of stain-inducing tannins), or even smoking. Remember that your composite resin filling is more porous than your natural teeth, and so is more likely to stain. Have these stained fillings inspected by your dentist. They can still be perfectly intact and functional, but you might want to have them replaced for cosmetic purposes.

Whether a dental filling is discoloured, or the discolouration is limited to around its edge, it's always necessary to have your dentist check it out, in case action is needed. 

For more information about dental examinations, contact a local dentist.