What's A Dental Cavity Liner, And Why May Your Tooth Need One?

If a dental cavity is deep enough, it stretches through the tooth's outer enamel and inner dentin to the tooth's nerve (also called the pulp). This sharply increases the tooth's risk of experiencing an infection of the pulp. If the pulp is unable to recover from this infection, it's likely you'll need a root canal (involving the removal of your inflamed pulp). But what about when the cavity is deepening, but hasn't quite reached the pulp? If your dentist simply fills such a cavity, will your pulp be adequately protected?

Proximity to the Pulp

A deep cavity that hasn't yet breached your pulp chamber can simply be filled, but given the cavity's proximity to the pulp, special measures can prove to be necessary. The filling itself must be reinforced. Failure to do so increases the cavity's chance of extending to the pulp chamber. This may be due to the continuing decay of the tooth beneath any filling that might be applied. This scenario isn't necessarily likely (removal of the decayed portion of the tooth is intended to halt further decay), but is possible. Alternatively, the biomechanical forces a tooth experiences (due to the pressure of biting and chewing) can rupture a sufficiently thin sliver of dentin, which might be the only thing that stands between your dental pulp and your tooth's cavity.

Cavity Liners

Due to these potential risks, your dentist must take special care when applying dental fillings close to the pulp. This involves the addition of a cavity liner. The cavity is a hollow, and a liner reinforces this hollow, readying it for the application of filling material. Although it's a two stage process, these types of fillings can be achieved in a single visit. You can expect it to take slightly longer than a standard filling.

Applying a Liner

The cavity liner itself can be made of the same material as the filling, namely a tooth-colored composite resin. It's applied, then heat-cured for immediate setting. The main filling is then applied. A dentist can also opt to apply a liner made of a glass ionomer filling material. This can have dental fluoride embedded in it, which is then slowly released into the tooth, meaning this option is useful when the tooth may benefit from some remineralization. 

Even without a cavity liner, a cavity close to your dental pulp can perhaps be successfully filled. But since the risk of damage to your pulp exists, your dentist may decide to offset this risk with the simple use of a cavity liner. A place like Dental Care Associates has more information.