Dental fillings are restorations that replace tooth structure lost to decay, cracks, or wear. A dentist removes the damaged portion of your tooth and fills the resulting hole with a durable material that restores the tooth’s shape and function. Fillings are one of the most common dental procedures, and several material options exist, each with trade-offs in cost, appearance, and longevity.
Types of Filling Materials
The material your dentist uses depends on the size and location of the cavity, your budget, and your cosmetic preferences. Four main types are used today.
Composite resin is the most popular choice for visible teeth. It’s a mixture of glass or quartz particles blended into a resin that can be shade-matched to your natural tooth color. Composite works well for small to mid-size cavities that face moderate chewing pressure. In dental surveys of private practices, composite fillings last a median of about 4 to 8 years, though under ideal conditions some last significantly longer, with studies reporting median survival times up to 17 years.
Dental amalgam is the classic “silver filling” made from a combination of mercury, silver, tin, and copper. It’s extremely durable and the least expensive option, costing roughly $50 to $150 for one or two teeth compared to $90 to $250 for composite. Amalgam fillings in private practice settings typically last 6 to 15 years, and some studies have recorded much longer lifespans. The obvious downside is appearance: amalgam is dark silver and highly visible.
Gold fillings (also called inlays or onlays) are an alloy of gold, copper, and other metals. Gold has been used in dentistry for over a thousand years because it’s exceptionally durable and well-tolerated by gum tissue. It’s also the most expensive option by a wide margin, ranging from $250 to $4,500. Few patients choose gold today, but it remains an option for back teeth where strength matters more than aesthetics.
Ceramic (porcelain) fillings are tooth-colored and highly resistant to staining. They’re typically fabricated in a dental lab as custom inlays or onlays, which makes them more precise but also more costly and time-consuming than composite.
Direct vs. Indirect Fillings
Most fillings are “direct,” meaning the dentist places the material into your tooth and shapes it during a single appointment. Composite and amalgam are both direct fillings.
Inlays and onlays are “indirect” restorations. Your dentist takes an impression of the prepared tooth, and a dental lab fabricates a custom piece that fits precisely into or over the damaged area. This requires a second visit for placement. Indirect fillings tend to last longer than direct ones because the lab-fabricated fit is more exact, and the materials don’t shrink over time the way direct composites can. That shrinkage in traditional fillings can eventually create tiny gaps where bacteria seep in, potentially leading to new decay underneath.
What Happens During the Procedure
Getting a direct filling is straightforward and typically takes 20 to 60 minutes. Your dentist numbs the tooth and surrounding area with a local anesthetic, then uses a small drill or laser to remove the decayed or damaged tissue. Once the cavity is clean, the filling material goes in. For composite fillings, a special curing light hardens the resin in layers. The dentist then polishes the surface smooth and checks your bite to make sure everything feels normal when you close your mouth.
Indirect fillings take two appointments. At the first visit, the dentist prepares the tooth and takes an impression. You’ll wear a temporary filling while the lab creates the final piece. At the second visit, the temporary is removed and the custom inlay or onlay is bonded into place.
When a Filling Is the Right Fix
Fillings work best for small to moderate cavities where enough healthy tooth structure remains to support the restoration. If a cavity is caught early, removing the decay and placing a filling preserves most of the original tooth.
Once a cavity reaches a certain size, though, drilling out the decayed material would compromise the tooth’s structural integrity. At that point, a crown (a cap that covers the entire visible portion of the tooth) is a better option. Teeth that have been weakened by large cavities or repeated dental procedures are also better candidates for crowns than fillings. Your dentist makes this call based on how much healthy tooth is left after the decay is removed.
Recovery and Sensitivity
Some sensitivity to hot, cold, or pressure is normal after getting a filling. For most people, this fades within two to four weeks as the tooth settles. You can eat and drink the same day, though with amalgam fillings you may be told to wait a few hours for the material to fully harden. Composite fillings are hardened with the curing light during the procedure, so they’re ready immediately.
Discomfort lasting more than a month is not typical. Sharp or worsening pain, difficulty eating, or swelling around the filled tooth are signs something needs attention, whether that’s a bite that’s slightly too high, irritation of the nerve inside the tooth, or a filling that didn’t seal properly.
Safety of Amalgam Fillings
The mercury content in amalgam has been a source of concern for decades. Once placed, amalgam fillings release tiny amounts of mercury vapor, particularly during chewing. For most adults, the FDA considers this exposure too low to cause harm. However, in 2020 the FDA issued updated recommendations advising certain groups to avoid amalgam whenever possible. Those groups include pregnant or nursing women, children under six, people with neurological conditions like multiple sclerosis or Parkinson’s disease, people with impaired kidney function, and anyone with a known sensitivity to mercury.
For these higher-risk groups, the FDA recommends non-mercury alternatives like composite resin or glass ionomer fillings. Importantly, the agency does not recommend removing existing amalgam fillings that are in good condition, because the removal process itself temporarily increases mercury vapor exposure and can result in losing healthy tooth structure. The risks of removal generally outweigh the benefits unless there’s a specific medical reason.
Cost Comparison
Filling costs vary by material, the number of tooth surfaces involved, and your location. For a basic one- to two-surface filling, typical price ranges are:
- Amalgam: $50 to $150
- Composite resin: $90 to $250
- Gold: $250 to $4,500
Dental insurance usually covers fillings as a basic restorative procedure, though many plans reimburse only at the amalgam rate even if you choose composite. That means you may pay the difference out of pocket if you opt for a tooth-colored filling on a back molar. Ceramic inlays and onlays fall into a higher cost bracket similar to gold because of the lab fabrication involved.
The cheapest filling isn’t always the best value. A well-placed composite in a small cavity can last well over a decade, while a poorly fitting filling of any material may fail within a few years and require replacement, adding cost and removing more tooth structure each time. The size of the cavity, the tooth’s location, and how well you maintain your oral hygiene all influence how long any filling will last.