If you haven’t already had to treat a cavity, then there’s a good chance you might at some point in your life (cavities affect over 90% of adults at least once). The good news is that, these days, we can treat most cavities with tooth-colored fillings, made from natural-looking composite resin rather than metal, like many older fillings. The differences between metal and tooth-colored composite resin fillings may seem obvious, but they extend to more than just the filling’s appearance. In many ways, a tooth-colored filling can also out-perform metal amalgam to create a more effective, longer-lasting restoration.

The Point of a Dental Filling

To understand the important differences between metal and tooth-colored fillings, you first should understand the full purpose of a dental filling. When your tooth develops a cavity, the hole in its structure will continue to grow until you treat the infection that causes it (known as tooth decay). After your dentist cleans the cavity, he can place a filling inside of it to restore your tooth’s strength and prevent oral bacteria from re-infecting it.

Amalgam vs. Composite Resin

Performance

Metal amalgam has been used for so long because it can endure even the most intense of your bite’s pressure. Still, the metals in dental amalgam cannot bond to your tooth’s structure, and it can therefore fail to protect the tooth from oral bacteria.

Composite resin is made from a mixture of finely-ground acrylic particles, and unlike metal, it can be bonded to your tooth.

Appearance

Perhaps the most obvious difference between metal and resin is their appearance. Amalgam is made of a number of trace metals, like tin and mercury, and therefore maintains a silver metallic look, which clashes with your tooth’s soft white appearance. By contrast, composite resin can be specially tinted to match your tooth’s exact color and hue, so your filling remains unnoticeable when you speak and smile.