Composite vs. Amalgam Fillings

Tooth Character

So your kids’ dentist found a cavity in one of your child’s teeth. Thank goodness it’s a small cavity, but it does need filled immediately. Should it be filled with silver amalgam or composite filling material? Is there a big difference between the two materials?

Amalgam Fillings

Composed of silver, copper, tin, and liquid mercury, amalgam is a popular cavity filling material due to its strength, ease of use, and ability to withstand repetitive biting forces exerted on molars. Affordable and offering good sealing properties, amalgam can be applied quickly on moist teeth, a feature that makes it an excellent choice when filling cavities in children. Concerns about mercury poisoning from amalgam fillings has also been thoroughly researched, with the FDA concluding that mercury level in amalgam fillings is so low that it poses no threat to a child or an adult’s health. 

Composite Fillings

Composite fillings are tooth-colored fillings made from powdered quartz particles and acrylic resin, which are used to fill cavities in all teeth but is an especially popular type of “aesthetic” filling for cavities in front teeth or teeth that are visible when a person smiles. Composite resin is available in a variety of off-white shades that can be matched to your child’s enamel color, so the filling is close to invisible. However, composite resin is not as strong as amalgam fillings and is best suited for front teeth, where chewing forces are less robust.

Composite vs Amalgam

While very small to medium-sized cavities on the sides of molars or pre-molars do well with amalgams, large cavities should be filled with composite resin. Although strong, silver fillings tend to break or fall out of large cavities. Moreover, when an amalgam falls out, the tooth has usually experienced some cracking and damage that requires the dentist re-prepare the area before refilling the cavity.

What the American Dental Association Says about Amalgam and Composite Fillings

The ADA reports that amalgam is the best option to fill cavities affecting molars while composite fillings may be used to fill cavities in front and teeth that are visible when smiling or talking. Your kids’ dentist will also help you make a decision by recommending which type of filling is more appropriate for your child’s cavity after considering the size, depth, and location of the cavity.