A dental filling is a material used to repair a tooth after decay has created a small hole, or cavity. Your dentist removes the damaged tissue and fills the space with a durable material that restores the tooth’s shape and strength. Fillings are one of the most common dental procedures, and most last between 5 and 20 years depending on the material used.
Why You Might Need a Filling
The primary reason for a filling is a cavity. When bacteria in your mouth produce acid that eats through tooth enamel, they create a hole that will keep growing if left untreated. A filling stops that progression by sealing off the space where bacteria were thriving.
Fillings can also repair teeth that have been chipped, cracked, or worn down from grinding. If the damage is relatively small, a filling is usually sufficient. More severe breakdown, where a large portion of the tooth is compromised, typically requires a crown (a cap that covers the entire tooth) rather than a filling.
Types of Filling Materials
Filling materials fall into two categories: direct fillings, which your dentist places and shapes right in your mouth during a single visit, and indirect fillings, which are custom-made in a lab and cemented into place at a second appointment.
Direct Fillings
- Composite resin: A tooth-colored mixture of resin with powdered quartz, silica, or glass. This is the most popular choice for visible teeth because it blends in naturally. Composite fillings typically last 5 to 10 years and cost between $100 and $400 per tooth.
- Amalgam: A silver-colored blend of mercury, silver, tin, zinc, and copper. Amalgam has been used for over 150 years and is extremely durable, lasting 10 to 15 years on average. It costs between $100 and $350 per tooth. The trade-off is appearance: it’s noticeably metallic.
- Glass ionomer: A tooth-colored material made from silica glass powder. It’s often used for fillings near the gum line or in baby teeth. Glass ionomer releases fluoride, which can help protect against further decay, but it’s less durable than composite or amalgam.
Indirect Fillings
- Porcelain: Made from minerals like feldspar, quartz, and kaolin, porcelain fillings (also called inlays or onlays) are tooth-colored, stain-resistant, and can last up to 15 years. They’re the most expensive option, ranging from $500 to $2,800.
- Gold: Gold mixed with silver, tin, copper, or palladium. Gold fillings are exceptionally strong and long-lasting but visually obvious. They typically cost $250 to $650.
What Happens During the Procedure
A standard filling appointment takes 20 to 60 minutes, depending on the size and location of the cavity. Here’s what to expect.
Your dentist starts by reviewing your X-rays and confirming the treatment plan, including which filling material makes sense for your situation. Then they apply a topical numbing gel to your gums before injecting a local anesthetic around the tooth’s nerve. You’ll wait a few minutes for the area to go fully numb.
Next comes decay removal. The dentist uses a high-speed drill to access the cavity and remove the bulk of the damaged tissue, then switches to a slower handpiece for more precise work near the nerve. For very small or shallow cavities, some dentists use lasers or air abrasion (a stream of fine particles) instead of a drill. Once all the decay is gone, the tooth is thoroughly cleaned to eliminate bacteria, and the remaining healthy structure is shaped so the filling material can bond securely.
For composite fillings, the material is applied in layers and hardened with a special curing light between each layer. The dentist then shapes and polishes the filling so it matches your bite. Amalgam fillings are packed into the prepared space and carved to fit. Indirect fillings like porcelain require an impression of your tooth at the first visit, a temporary filling while the lab creates the final piece, and a second visit for placement.
Recovery and Sensitivity
Some sensitivity after a filling is normal. Most people notice improvement within the first 48 hours, and shallow to moderate fillings heal completely within about two weeks. Deep fillings placed close to the nerve can take three to four weeks for sensitivity to fully resolve.
One common issue is a filling that sits slightly too high, which creates an uneven bite and pain when chewing. This is an easy fix: your dentist can adjust the height in a quick follow-up visit.
Certain symptoms, however, signal something beyond normal healing. Pain that gets worse over several days rather than gradually improving, spontaneous throbbing that happens without any trigger, or lingering pain that continues for minutes after drinking something cold or eating something sweet all suggest the inner tissue of the tooth may be inflamed or infected. Visible swelling around the treated tooth, a bad taste or odor, fever, or pus discharge point to a possible abscess. If any of these develop, a follow-up evaluation is important because the tooth may need additional treatment.
How Long Fillings Last
No filling lasts forever. Amalgam fillings generally hold up for 10 to 15 years, composite fillings for 5 to 10 years, and porcelain fillings for up to 15 years. Gold is often the longest-lasting material, sometimes exceeding 20 years.
Several factors influence lifespan. Fillings on chewing surfaces endure more force and wear out faster. Teeth grinding shortens filling life significantly. Poor oral hygiene allows new decay to develop around the edges of a filling, undermining it from below. Regular dental checkups catch deteriorating fillings before they fail completely, which saves you from more invasive (and expensive) repairs later.
The Safety Question Around Amalgam
Because amalgam contains mercury, its safety has been debated for decades. The FDA’s current position is that available evidence does not show mercury exposure from amalgam fillings causes adverse health effects in the general population. However, the FDA does identify specific groups that may face greater risk: pregnant women, women planning to become pregnant, nursing mothers, children under six, and people with neurological disease, impaired kidney function, or a known allergy to mercury or other amalgam components.
For anyone in these groups, the FDA strongly encourages non-amalgam alternatives like composite resin or glass ionomer, provided those materials are appropriate for the tooth being treated. Importantly, the FDA does not recommend removing existing amalgam fillings that are in good condition. Removing an intact amalgam filling means losing healthy tooth structure unnecessarily and actually increases your mercury exposure temporarily from the vapor released during removal.
Cost and Insurance Coverage
Dental fillings range from about $100 to over $1,000 per tooth, with material choice being the biggest cost driver. Composite and amalgam fillings are the most affordable at $100 to $400, while porcelain can reach $2,800 for complex restorations.
Most dental insurance plans classify fillings as a basic service and cover them at around 80%. So a $400 composite filling would leave you with roughly $80 out of pocket after insurance pays its share. Without insurance, you pay the full amount, though many dental offices offer payment plans or discount memberships. Location matters too: fillings in major cities tend to cost more than in smaller markets, and a filling on a molar (which is harder to access and takes longer) usually costs more than one on a front tooth.