What Dentists Use to Fill Cavities: A Simple Guide to Dental Filling Materials

Think back to when you heard, “You have a cavity!” at the dentist. Maybe you were surprised, worried, and had a lot of questions at once. What happens next? What does the dentist actually put in your tooth? And—maybe most important—how do you know which filling is best for you or your child?

Take a breath. You are not alone. Almost everyone will get a cavity at some point. Fixing your tooth does not have to be confusing or scary. Let’s go over everything you need to know about what dentists use to fill cavities, why they pick a certain material, and how you can be involved with your own dental health.

In This Article

• What Are Cavities and Why Do They Need Fillings?
• The Main Types of Dental Filling Materials
• How Dentists Choose the Right Filling Material
• What to Expect During a Dental Filling Procedure
• Taking Care of Your Dental Fillings
• When Do Dental Fillings Need to Be Replaced?
• Your Healthy Takeaway: Empowering Your Dental Choices

What Are Cavities and Why Do They Need Fillings?

Let’s start from the beginning.

A cavity, or tooth decay, is basically a hole in your tooth. This hole is made when bacteria break down sugar from what you eat and drink, making acid that eats away at your tooth’s hard outer layer (enamel). Over time, these acids can make a hole through the enamel, getting into the softer part below called dentin, and sometimes even reaching the inside part with nerves (the pulp).

Why Is Filling a Cavity So Important?

Think of your tooth like a castle. The enamel is your strong wall, keeping everything inside safe. Once decay makes a hole in the wall, bacteria can keep getting in and attack the softer layers. Without help, the damage gets worse—it cannot heal by itself.

Dentists use fillings to:

• Stop decay: They take out the bad part and seal up the hole, so things do not get worse.
• Restore function and comfort: Fillings rebuild your tooth’s shape so you can bite and chew normally.
• Prevent pain and infection: Deep cavities can make your tooth hurt, feel sensitive, get infected, or even be lost—fillings stop that.

So, getting a filling fixes the problem and keeps your smile safe from bigger trouble later.

The Main Types of Dental Filling Materials

Not all fillings are the same. Dentists have a bunch of materials to pick from, and each one has its own good and bad sides. Here’s a simple look at what your dentist might use and why.

1. Amalgam (Silver Fillings)

What Is It?

Amalgam has been around for over 100 years. It is made by mixing mercury with metals like silver, tin, and copper.

It is the workhorse of dental fillings—strong and reliable, but not pretty.

Advantages

• Very strong: Good for back teeth that do a lot of chewing.
• Lowest cost: Usually the cheapest choice.
• Works even if wet: Fine even if the area in your mouth isn’t completely dry.
• Lasts a long time: With normal care, can last over 10 years—sometimes up to 20.

Disadvantages

• Looks like metal: Not tooth-colored, so it stands out as a gray spot.
• Mercury worries: About 50% mercury, but the American Dental Association and the FDA say it is safe for most people.
• No tooth bonding: Held in by shape, not glued on.
• May need to remove more healthy tooth: Sometimes, more tooth must be taken out for a good fit.

Is It Still Used?

Yes, but not as much as before, especially in visible teeth or for kids and pregnant women because of ongoing studies and world efforts to cut down on mercury use.

2. Composite Resin (Tooth-Colored/White Fillings)

What Is It?

Composite resin fillings are a plastic material with tiny glass or quartz bits. Dentists shape it right in your mouth, then use a blue light to harden it so it sticks to your tooth.

Advantages

• Looks natural: Can match your tooth color so well that people won’t notice it.
• No metal or mercury: All plastic and glass.
• Bonds to tooth: Less drilling, so most of your tooth can stay.
• Versatile: Can also fix chips, cracks, or be used for minor cosmetic fixes.

Disadvantages

• Not as tough: Not as strong as metal—may wear down quicker in spots where you bite hard.
• Can stain: May darken over time if you drink a lot of coffee or red wine.
• Costs more: Usually a bit pricier than amalgam.
• More steps: Takes more time to put in.

Quick Fact

Composite is now the #1 choice in many places, thanks to better technology and the wish for natural-looking smiles.

3. Gold Fillings (Inlays/Onlays)

What Is It?

Gold fillings are made from gold that’s mixed with other metals, shaped in a lab outside your mouth, and then glued in. They’re often used for bigger repairs, not small basic fillings.

Advantages

• Toughest of all: Gold can last the longest—even past 20 years.
• Usually safe for allergies: Most people do not react to gold.
• Gentle on other teeth: Gold does not wear down your other teeth.

Disadvantages

• Expensive: Usually the most pricey choice, even up to 10 times the price of amalgam.
• Noticeable: Gold is not tooth-colored.
• Needs two dentist visits: First to prepare and do a temporary, second to put in the gold.

4. Porcelain or Ceramic Fillings (Inlays/Onlays)

What Is It?

Porcelain or ceramic fillings are also made outside your mouth, sometimes using 3D printers and lasers, then glued into your tooth.

Advantages

• Look just like real teeth: Almost impossible to tell from your own teeth.
• Don’t stain easily: Coffee and tea don’t affect them much.
• Strong and lasts: Good for big repairs needing both looks and strength.

Disadvantages

• Costly: Usually similar or more than gold.
• Can chip: More likely if you grind your teeth.
• Can wear down other teeth a bit: Especially if you bite hard.
• Needs two visits: Since the filling is made in a lab.

Tip: If you are thinking about porcelain, a special dental ceramics lab may help make sure the fit and look are just right.

5. Glass Ionomer Cement (GIC)

What Is It?

GIC is a mix of acrylic and a type of glass powder. Not common for adult fillings but great for quick fixes, kids’ teeth, or areas that don’t get heavy biting.

Advantages

• Releases fluoride: This helps stop new cavities.
• Quick and gentle: Great for baby teeth or as a temporary fix.
• Bonds to tooth: Sticks without glue.
• Cheaper: Usually not costly.

Disadvantages

• Not very strong: Not meant for places where you chew a lot.
• Doesn’t last as long: Usually 1-5 years—think of it as a first filling.
• Not clear like real teeth: Looks more chalky or “plastic.”

How Dentists Choose the Right Filling Material

There’s no single answer. Every cavity and every person is different. Here’s what dentists think about before picking a filling:

Where Is the Cavity?

• Front teeth: Usually get white or porcelain fillings to look natural.
• Back teeth: Need to be strong, so silver, gold, or strong composites are used.

How Big or Deep Is the Hole?

• Small, shallow holes: Composite or glass ionomer often works well.
• Big or deep holes: May need something tougher, like porcelain or gold.

Your Life and What You Want

• Want best looks? Composite or porcelain is likely.
• Need something cheaper? Silver or glass ionomer may be suggested.

Do You Grind Your Teeth?

• Gold or some strong ceramics can handle teeth grinding better.

Allergies or Sensitivities

• Rare, but if you’re allergic to some metals, your dentist won’t use those.

Insurance & Cost

• Every dental plan is different. Some only cover cheap fillings for back teeth. Others pay more for the cheaper option.

What About Safety—Is Mercury or BPA a Risk?

You might hear about mercury in silver fillings or BPA in some plastics. Here’s what health experts say:

• Amalgam (mercury): Considered safe for most adults, but kids under six, pregnant people, or those with certain health problems may want to choose something else. The FDA and ADA say it is okay for most.
• Composite resin (BPA): Most modern fillings are BPA-free or have a tiny amount. If you worry, ask the dentist for a BPA-free choice.

Bottom line: Always ask your dentist if you have safety questions. They are there to help.

What to Expect During a Dental Filling Procedure

Not sure what will happen when you get a filling? Here’s what to expect for most people:

1. Diagnosis

• The dentist looks at your teeth and may take X-rays.

2. Numbing (Local Anesthesia)

• You get a little shot to numb the tooth and gum—no pain, just weird “fat lip” feeling.

3. Removing the Decay

• The dentist uses a drill or laser to clean out the decay and shape the space for a filling.

4. Cleaning and Preparation

• They clean and dry the area, and may add a special liner if your cavity was deep.

5. Placing the Filling

• Composite fillings: Put in layer by layer, each one hardened with blue light.
• Amalgam: Packed and shaped quickly.
• Gold/ceramic inlays: You get a temporary filling while yours is made at the lab. Second visit, it is glued in.

6. Finishing Up

• Dentist trims, checks your bite, and polishes it smooth.

How Long Does It Take?

Simple fillings can be done in less than 30 minutes. Bigger or lab-made fillings may need two visits.

Taking Care of Your Dental Fillings

Want your filling to hang on for a long time? How you look after your mouth matters.

Do:

• Brush and floss daily: This stops new cavities and keeps fillings clean.
• Go for dental checkups: Cleanings catch problems early.
• Watch what you eat: Sticky candy or chewing ice can damage fillings.

Don’t:

• Bite hard things: Like pens, ice, or hard candy—they can break your fillings.
• Ignore pain or sensitivity: If it keeps bothering you, let your dentist know.

What If You Grind Your Teeth?

• You might want a night guard, which can be made by a night guard dental lab, to protect both your fillings and teeth.

When Do Dental Fillings Need to Be Replaced?

Fillings do not last forever. Here’s when you should check in:

• You feel pain or sensitivity: New or lingering pain means get it checked.
• You spot a crack, chip, or missing bit: Sometimes you can wiggle it!
• Filling feels rough or high: Rough edges can trap germs and food.
• You see discoloration: Dark edges could mean decay underneath.
• X-rays find a problem: Sometimes issues show up that you can’t see or feel.

About half of all filling replacements happen because of new decay under or around them; cracks and breaks are next most common. Usually, silver fillings last 10-15 years, composites and porcelain around 5-10 years (sometimes longer), and glass ionomer less.

Your Healthy Takeaway: Empowering Your Dental Choices

Let’s sum it up so you know what to expect.

What Did We Learn?

• Fillings fix cavities and restore your tooth so you can keep using it.
• Fillings come in several materials: Silver (amalgam), white (composite), gold, porcelain, and glass ionomer.
• Each material is different: The best choice depends on where the tooth is, money, allergies, if you care how it looks, and what your dentist suggests.
• Safety matters: Experts say silver is safe for most, but ask your dentist if you are worried or want something else.
• Getting a filling is quick and usually not painful: Most fillings are done in one visit (except gold and porcelain, which may take two).
• Care for fillings like your own teeth: Brush, floss, eat healthy, and see the dentist regularly.
• All fillings end up needing a change: Watch for pain, cracks, or changes, and keep up with checkups.

What’s Next?

• If your dentist says you need a filling—ask what types they suggest and why.
• Tell the dentist what you want or if anything worries you—they work with you, not just your teeth!
• Good brushing, flossing, and dentist visits keep fillings (and your mouth) healthy.

Still Have Questions or Want a Second Opinion?

Dentists work as a team for your care. If you ever need special work—like crowns or a tricky porcelain repair—a skillful 3D dental lab might also help you get the best results.

Frequently Asked Questions

How long does a filling last?

• Amalgam: 10-15+ years
• Composite: 5-10+ years
• Gold: 15-20+ years
• Porcelain/Ceramic: 10-15+ years
• Glass Ionomer: 1-5 years

Is the procedure painful?

Not usually—the numbing should make it comfortable. Soreness or sensitivity for a few days is normal, especially with deep fillings.

Can I eat right away?

If you had a composite (white) filling, you can eat when you are no longer numb. If it’s a silver filling, you might want to wait a few hours. Avoid hard, sticky, or hot foods at first.

Is there a chance of allergy?

Rare, but can happen—especially with some metals. Always tell your dentist about known allergies.

How do I make fillings last longer?

Brush and floss every day, avoid bad food habits, visit the dentist often, and fix any problem (like pain or a crack) right away.

Your dental health does not have to be a mystery. Ask questions, learn your options, and keep up with simple good habits—your fillings (and your smile) can last many years.

Be proactive, stay informed—and remember, your dentist is there to help you every step of the way.

*Medically checked by a licensed dentist for accuracy.

References: American Dental Association (ADA), U.S. FDA, World Health Organization, CDC.*