Amalgam vs Composite Fillings: Which One Should You Choose?

When a cavity needs filling, the material question usually comes down to two options: amalgam, the traditional silver-colored metal alloy, and composite, the tooth-colored resin most patients ask for by default today. Both are safe and effective, but they're not interchangeable — the right choice depends on where the cavity is and what matters most to you.

What Each Material Actually Is

Amalgam

A mixture of metals — mostly silver, tin, and copper — bound with a small amount of elemental mercury. It's been used safely in dentistry for over a century and remains one of the most durable filling materials available.

Composite

A tooth-colored resin made of a plastic and fine glass or ceramic particles, which bonds directly to the tooth and can be shaded to match natural enamel almost exactly.

How They Actually Compare

Durability

Amalgam generally outlasts composite in large fillings and high-pressure back teeth — well-placed amalgam fillings commonly last 10–15 years or longer. Composite has improved significantly but still tends to wear faster under heavy chewing forces.

Appearance

Composite is essentially invisible once placed. Amalgam is unmistakably silver-gray, which matters mainly for visible front and premolar teeth.

Tooth preparation

Composite bonds directly to the tooth, so less healthy tooth structure needs to be removed to place it. Amalgam relies on mechanical retention, which requires removing slightly more tooth structure to hold the filling in place.

Procedure time and sensitivity to moisture

Amalgam placement is more forgiving of a slightly wet field, useful for hard-to-isolate back teeth. Composite requires a completely dry field to bond properly, which can extend procedure time in difficult positions.

Cost

Amalgam is generally cheaper than composite, largely due to material and placement-time differences.

How Dentists Actually Decide

For large fillings on back molars that take significant chewing force, amalgam's durability often makes it the more practical long-term choice. For visible teeth, smaller cavities, or patients who specifically want a metal-free restoration, composite is usually preferred. Some dentists also factor in whether isolating the tooth from saliva will be difficult — a real consideration for young children or hard-to-reach molars.

Is Amalgam Safe?

Major health and dental bodies, including the WHO and dental associations worldwide, consider amalgam fillings safe for most patients. The mercury is chemically bound within the alloy and released in trace amounts far below any established safety threshold. Pregnant patients and those with specific mercury sensitivities are generally advised to discuss alternatives with their dentist.

The Bottom Line

Neither material is universally "better" — the right filling depends on the tooth's location, the size of the cavity, and what you personally prioritize between longevity, appearance, and cost. Your dentist can walk through which factors apply to your specific tooth.