Composite vs. Amalgam Fillings: What's the Difference?

A Cochrane review of randomized trials found that composite fillings failed at nearly double the rate of amalgam fillings in back teeth, largely due to a higher risk of new decay forming around the edges of the filling. That number surprises many patients, since composite has become the more common choice in most restorative dentistry practices today.

The real answer to which material is better depends on where the cavity is and what the patient actually cares about most, which is exactly the kind of conversation worth having before dental filling treatment in Cherry Hill, NJ, begins, rather than after.

Why Amalgam Still Wins on Raw Durability

Amalgam has been used in dentistry for over 150 years, and its track record reflects that. The metal alloy resists wear well under the heavy chewing forces found in molars, and the Cochrane data above lines up with decades of clinical use showing it holds up longer than composite in posterior teeth specifically. The FDA's own description of amalgam calls it strong and long-lasting, noting it is less likely to break than some alternative materials.

That durability comes with a trade-off, though. Placing an amalgam filling typically requires removing more healthy tooth structure to create a shape the material can mechanically lock into, since amalgam does not bond to the tooth the way composite does.

Why Composite Has Become the Default Anyway

Composite fillings bond directly to the tooth using an adhesive, which means less drilling and a more conservative removal of healthy structure. They also match the natural color of a tooth, which matters most for fillings, so anyone might notice when a patient smiles or talks. For front teeth and other visible spots, that cosmetic advantage generally outweighs the durability gap seen in molars.

Safety questions come up occasionally, too, since amalgam contains mercury. The FDA's official safety communication recommends that non-mercury materials, such as composites, be used when possible for specific higher-risk groups, including pregnant women and young children, while noting that amalgam remains generally safe for the broader adult population. This is a conversation best had directly with a dentist rather than settling for an internet search, since individual health history affects the calculation.

In practice, the choice often comes down to a few practical factors:

• Location in the mouth: back teeth under heavy chewing pressure may favor the durability of amalgam

• Visibility: front teeth or anywhere the filling shows, usually calls for composite

• Cavity size: very large cavities sometimes favor amalgam's strength over composite's more limited support

• Personal risk factors: pregnancy or certain health conditions may steer the choice toward composite

• Long-term plans: a filling meant to last decades in a molar may lean toward amalgam despite the extra tooth preparation

What This Actually Means for the Visit Itself

The choice of material affects more than just how the filling looks afterward. An amalgam filling typically hardens on its own over several hours, while a composite filling is cured immediately with a special light before the patient leaves the chair. That difference used to matter more for eating right after an appointment, though most patients receiving dental filling treatment today get composite regardless of which tooth is involved, unless there's a specific clinical reason to choose otherwise.

How This Gets Decided During a Visit

At Dental Arts of Haddonfield, the dentist examines the specific tooth, its location, and the size of the cavity before recommending a material rather than defaulting to whichever crown or filling option is more commonly used. Dr. Heidi Choi and Dr. Shiv walk patients through the reasoning before any dental filling treatment begins. This ensures the decision doesn't feel arbitrary, especially for molars, where the durability difference is largest. New patients can also ask about current exam specials when scheduling a visit.

Schedule Dental Fillings Treatment in Cherry Hill, NJ

Whether a cavity calls for composite or amalgam depends on details that are easiest to sort out chairside rather than in advance. Dental Arts of Haddonfield offers dental filling treatment in Cherry Hill, NJ, with a straightforward explanation of which material fits your specific tooth. Call the office to schedule an exam and get a clear recommendation, rather than guessing.