Fillings in baby teeth typically last between 5 and 10 years, depending on the filling material, the location of the tooth, and how well the child cares for their teeth. Composite (tooth-colored) fillings last about 5 to 7 years, amalgam (silver) fillings last 10 to 15 years, and glass ionomer fillings last 3 to 5 years. In many cases, a filling placed in a baby tooth only needs to survive until that tooth falls out naturally, which means even a shorter-lasting material can do its job.
The real question most parents have is not just “how many years” but whether the filling will protect their child’s tooth long enough. Baby teeth follow a predictable schedule. The front teeth fall out around ages 6 to 7, and the back molars stay until ages 9 to 13. A filling placed in a 4-year-old’s molar needs to last roughly 5 to 9 more years. That timeline changes the math for every child. Below, we break down what affects filling longevity, which materials work best, what to watch for, and how to help your child’s fillings last as long as possible.
How Long Do Different Types of Fillings Last in Baby Teeth?
Different types of fillings last different lengths of time in baby teeth because each material has a different level of strength, bonding ability, and resistance to chewing pressure. The three filling materials used most often in pediatric dentistry are composite resin, amalgam, and glass ionomer cement. Each one has a specific role depending on the size of the cavity, the tooth’s location, and the child’s age.
Composite resin (tooth-colored) fillings last approximately 5 to 7 years in children. Composite is a blend of plastic resin and finely ground glass particles that bonds directly to the tooth surface through an adhesive process called acid etching. This bonding mechanism locks the filling to the enamel and dentin, creating a tight seal. Composite fillings match the natural color of the tooth, which makes them the most popular choice for both front and back teeth in children today. According to ADA survey data, fewer than 8 percent of posterior restorations placed by U.S. dentists in 2025 were amalgam, meaning composite has become the standard material for pediatric fillings.
Composite’s main limitation is its sensitivity to moisture during placement and its moderate resistance to heavy chewing forces. Back molars absorb significant biting pressure during meals, which wears composite down faster than it wears in front teeth. A study published in the Japanese Dental Science Review found that at least 60 percent of composite restorations survive beyond 10 years when proper materials and techniques are applied. In children, the expected range is shorter because baby teeth have thinner enamel and because children’s diets and brushing habits create more stress on the material.
Amalgam (silver) fillings last 10 to 15 years and sometimes longer. Amalgam is a mixture of metals including silver, tin, copper, and mercury. It does not bond to the tooth the way composite does. Instead, the dentist shapes the cavity so the amalgam locks into place mechanically. This mechanical retention gives amalgam exceptional durability under heavy chewing forces, especially in molars. A systematic review published in PubMed Central in 2025 found that amalgam restorations show median survival times exceeding 16 years, compared to 11 years for composite in permanent teeth.
However, amalgam use has declined sharply in pediatric dentistry. The FDA recommends that dentists avoid placing amalgam fillings in children under 6 and in other high-risk patients. The Minamata Convention on Mercury set a global phase-down target, and the European Union banned amalgam for children under 15 in 2018. Most pediatric dental practices, including ours, use tooth-colored composite as the primary filling material for children.
Glass ionomer cement fillings last approximately 3 to 5 years. Glass ionomer is a fluoride-releasing material that bonds chemically to the tooth without acid etching. The fluoride release provides a protective benefit by strengthening the surrounding enamel and reducing the risk of new decay around the filling. Pediatric dentists often use glass ionomer for very young children, for small cavities in non-load-bearing areas, or as a temporary restoration when a longer-lasting filling is not yet practical. An umbrella review published in the Journal of Functional Biomaterials in 2024 confirmed that glass ionomer has a shorter functional lifespan than composite but offers valuable cavity-prevention properties in high-risk children.
| Filling Material | Typical Lifespan | Best Used For | Key Advantage |
|---|---|---|---|
| Composite Resin (White) | 5 to 7 years | Front and back teeth | Tooth-colored, bonds directly to enamel |
| Amalgam (Silver) | 10 to 15 years | Back molars under heavy pressure | Exceptional durability |
| Glass Ionomer | 3 to 5 years | Small cavities, young children | Releases fluoride, protects surrounding enamel |
The material your pediatric dentist chooses depends on the size of the cavity, which tooth is affected, and how many years the tooth needs to stay in the mouth. Composite is the default for most pediatric fillings today because it bonds directly to the tooth, matches the natural color, and holds up well for the lifespan of a baby tooth.
Does the Location of the Tooth Affect How Long the Filling Lasts?
Yes, the location of the tooth directly affects how long a filling lasts. Fillings placed in back molars experience significantly more chewing force than fillings in front teeth. Every time a child bites, chews, or grinds food, the molars absorb the bulk of that pressure. This repeated force wears down filling material faster, especially composite resin, which is softer than natural tooth enamel.
Front teeth bear less chewing pressure, so fillings placed there tend to last longer. However, front teeth are more exposed to habits like nail biting, chewing on pencils, or opening packages with teeth. These habits create lateral stress that can crack or chip a filling even in a low-pressure area. Children who grind their teeth at night, a condition called bruxism, put additional strain on both front and back fillings. Bruxism generates forces that exceed normal chewing pressure by a significant margin, and it can shorten a filling’s lifespan by several years. We see this frequently in children at our Yorktown Heights office, and a simple nightguard can make a real difference.
The size of the cavity also matters. A larger cavity requires more filling material, and a bigger filling has more surface area exposed to chewing forces and temperature changes. Larger fillings in molars break down faster than small fillings in the same location. This is one reason pediatric dentists encourage catching cavities early through regular preventive care and checkups.
Can a Filling in a Baby Tooth Last Until the Tooth Falls Out?
Yes, a filling in a baby tooth can last until the tooth falls out naturally, and that is the goal of every pediatric filling. The filling does not need to last 20 or 30 years. It only needs to protect the tooth until the permanent tooth underneath is ready to push the baby tooth out.
Baby teeth follow a predictable exfoliation schedule. The lower front teeth (central incisors) are usually the first to go, falling out around ages 6 to 7. The upper front teeth follow shortly after. The canines and first molars typically fall out between ages 9 and 12. The second molars, the very back baby teeth, are the last to go, usually between ages 10 and 13. According to the American Academy of Pediatric Dentistry (AAPD), preserving baby teeth until they are ready to fall out naturally is one of the most important goals of pediatric dentistry.
This means a composite filling placed in a 5-year-old’s front tooth only needs to last 1 to 2 years before that tooth falls out on its own. A composite filling placed in a 3-year-old’s back molar, on the other hand, needs to last 7 to 10 years. In cases where the cavity is large and the molar needs protection for many years, a pediatric dentist may recommend a pediatric crown instead of a filling to provide stronger, longer-lasting coverage.
Is It Worth Getting Fillings on Baby Teeth?
Yes, fillings on baby teeth are worth getting because untreated cavities cause pain, infection, and damage to the permanent teeth developing underneath. Many parents wonder whether it makes sense to fill a tooth that will fall out anyway. The answer is almost always yes, and the reasons go far beyond the baby tooth itself.
Baby teeth serve three critical functions. First, they allow children to chew food properly, which is the first step in nutrition and healthy growth. A child with painful teeth may avoid crunchy fruits, vegetables, and proteins, limiting the nutrients their body needs. Second, baby teeth support speech development. Children form sounds like “th,” “f,” and “s” using their front teeth. Missing or damaged teeth can interfere with clear pronunciation during the years when speech patterns are forming. Third, baby teeth act as space holders for permanent teeth. Each baby tooth reserves a spot in the jaw for the adult tooth below it. When a baby tooth is lost early because of decay, the surrounding teeth drift into the gap, which can cause the permanent tooth to come in crooked or impacted.
According to the CDC, half of all children aged 6 to 9 have had cavities in their baby or permanent teeth. The AAPD reports that childhood tooth decay is four times more common than early childhood obesity and five times more common than childhood asthma. Despite being so widespread, cavities are almost entirely preventable with proper care, and fillings are the most common treatment once a cavity has formed.
Do 5 Year Olds Need Cavities Filled?
Yes, 5 year olds need cavities filled in most cases. At age 5, a child’s front teeth may fall out within a year or two, so a dentist might monitor a very small cavity in a front tooth rather than fill it. But the back molars at age 5 will stay in the mouth until age 9 to 13. Leaving a cavity in a molar untreated for that long allows the decay to spread deeper, potentially reaching the nerve and causing an infection that requires a pulpotomy or extraction.
Baby teeth have thinner enamel than adult teeth, so decay spreads faster. What starts as a small spot can become a deep cavity within months. The AAPD emphasizes that early treatment with a simple filling prevents the need for more extensive procedures later. According to the CDC, about 1 in 5 children ages 5 to 11 has at least one untreated cavity, which means millions of children are walking around with decay that could be treated quickly and painlessly.
When Is It Too Late to Fix a Cavity in a Baby Tooth?
It is too late to fix a cavity in a baby tooth with a simple filling when the decay has reached the nerve of the tooth or when the tooth is very close to falling out. A filling works by removing the decayed portion and sealing the remaining healthy tooth structure. When the decay extends into the pulp (the soft tissue inside the tooth that contains the nerve and blood supply), a filling alone cannot stop the infection.
In those cases, the pediatric dentist may recommend a pulpotomy, which removes the infected pulp tissue and preserves the rest of the tooth. A crown is usually placed over the tooth after a pulpotomy to protect it. If the infection is too severe or the tooth structure is too compromised, an extraction may be the only remaining option. After an extraction, a space maintainer holds the gap open so the permanent tooth can come in properly.
If the baby tooth is already loose and close to falling out on its own, a filling is usually unnecessary. The pediatric dentist evaluates the child’s tooth eruption timeline and X-rays to determine whether the tooth has enough time left to justify treatment. This is one reason regular dental checkups are so important. Catching decay at the earliest stage, when it is still in the enamel layer, makes treatment simple, fast, and painless.
How Do You Know If Your Child Needs a Filling?
You know your child needs a filling when the dentist detects a cavity on an X-ray or during a visual exam, or when your child reports pain, sensitivity, or discomfort in a tooth. Many cavities in baby teeth cause no symptoms at all in the early stages. The enamel breaks down silently, and the child feels nothing until the decay reaches deeper layers of the tooth.
Some signs of a cavity that parents can watch for include visible brown or white spots on a tooth, sensitivity to hot or cold foods, pain when chewing, or complaints that a tooth “feels funny.” However, the most reliable way to detect cavities early is through regular dental visits. Pediatric dentists use digital X-rays that reveal decay between teeth and below the enamel surface, areas that are invisible to the naked eye.
The AAPD recommends that children visit the dentist every six months starting by their first birthday. These routine checkups catch cavities when they are small enough for a simple filling. Children who skip regular visits often present with larger cavities that require crowns, pulpotomies, or extractions instead of fillings.
What Are the Signs of a Failed Filling?
The signs of a failed filling include tooth sensitivity, pain when biting or chewing, visible cracks or chips in the filling, discoloration around the filling, or a rough or uneven edge the child can feel with their tongue.
Sensitivity to hot, cold, or sweet foods and drinks often signals that the seal between the filling and the tooth has weakened, allowing temperature changes and sugar to reach the dentin layer underneath. Pain when biting down can mean the filling has cracked or that new decay has formed beneath the restoration. Visible damage, such as a missing piece of filling material, dark staining around the edges, or a noticeable gap between the filling and the tooth, indicates the filling is no longer protecting the cavity.
Children may not always describe these symptoms clearly. Parents should watch for signs like avoiding certain foods, chewing only on one side, or touching the jaw frequently. Any change in how your child eats or talks about their teeth warrants a visit to the dentist. Regular six-month checkups allow the dentist to examine fillings with specialized instruments and X-rays, catching problems before they become painful.
Do Cavities Come Back After Fillings?
Yes, cavities can come back after fillings. A filling repairs the damaged portion of the tooth, but it does not make the tooth immune to future decay. The natural enamel surrounding the filling remains vulnerable to bacteria, acid, and plaque buildup. When new decay forms at the edge of an existing filling, dentists call it recurrent caries or secondary caries.
Recurrent caries develop when bacteria infiltrate the margin where the filling meets the natural tooth. Over time, normal wear and tear can create microscopic gaps at this junction. Plaque accumulates in these gaps, and the acid produced by bacteria erodes the enamel around the filling. Poor brushing and flossing habits accelerate this process. A diet high in sugar and acidic drinks also weakens the seal between filling and tooth.
According to research published in PubMed Central, secondary caries is the most common cause of composite filling failure. This is why oral hygiene after a filling is just as important as before. Brushing twice a day with fluoride toothpaste, flossing daily, and limiting sugary snacks all protect the filling and the surrounding tooth structure. Fluoride treatments at the dentist’s office further strengthen the enamel and reduce the risk of recurrent decay.
Do Teeth Rot Under Fillings?
Teeth can rot under fillings when the seal between the filling material and the tooth breaks down, allowing bacteria to enter the space underneath. This breakdown happens gradually over years of chewing, temperature changes, and normal wear. A filling that was placed correctly and bonded well may eventually develop a microscopic leak as the material ages. Bacteria colonize this leak and produce acid that erodes the tooth from within, often without any visible signs on the surface.
Decay under a filling is particularly concerning because it is hidden. The filling covers the problem, and the child may not feel pain until the decay has spread significantly. This is why pediatric dentists use X-rays at routine checkups to look beneath existing fillings. Digital X-rays reveal shadows and dark areas under restorations that indicate decay forming below the surface.
Can I Wait 2 Years to Fill a Cavity?
No, waiting 2 years to fill a cavity in a baby tooth is not recommended because decay does not stop growing on its own. A cavity is an active bacterial infection in the tooth. The bacteria continue to produce acid that breaks down enamel and dentin every day. In baby teeth, this process moves faster than in adult teeth because the enamel layer is thinner and the pulp chamber is larger.
A small cavity caught at a routine visit can be treated with a quick, painless filling. That same cavity left untreated for two years may grow deep enough to reach the nerve, turning a simple filling into a pulpotomy, crown, or extraction. According to the AAPD, untreated early childhood caries can penetrate deep into the nerve tissue, causing infections that may require hospitalization in severe cases. The CDC states that untreated cavities can lead to abscess, a severe infection that can spread to other parts of the body.
Children also miss school because of dental pain. The CDC reports that approximately 34 million school hours are lost each year due to unplanned dental care. A study published in the American Journal of Public Health found that children with poor oral health were nearly three times more likely to miss school because of dental pain. Filling a cavity early prevents all of these outcomes.
Is It Bad to Have Cavities for Years?
Yes, it is bad to have cavities for years because untreated decay continues to destroy the tooth and can lead to pain, infection, and damage to permanent teeth. Bacteria responsible for cavities do not go away on their own. They multiply, produce acid continuously, and eat through the tooth layer by layer. In baby teeth, which have thinner enamel and larger nerve chambers, this progression from surface cavity to deep infection can happen in a matter of months.
The World Health Organization reports that 514 million children worldwide have dental caries in their primary teeth. The AAPD notes that children who have cavities in their baby teeth are at significantly higher risk for cavities in their permanent teeth. The bacteria remain in the mouth even after a baby tooth falls out, ready to attack the new permanent teeth as they come in. Treating cavities promptly breaks this cycle of infection and protects the child’s long-term oral health.
What Happens If a Filling Falls Out of a Baby Tooth?
If a filling falls out of a baby tooth, the exposed cavity is vulnerable to bacteria and new decay, so you should contact your pediatric dentist promptly. A lost filling leaves an open space where food particles and plaque can collect. The tooth underneath is already weakened from the original cavity, making it more susceptible to rapid decay and sensitivity.
Here is what to do right away:
- Check to make sure your child did not swallow the filling. If they did, it will pass harmlessly through the digestive system in most cases.
- Rinse your child’s mouth gently with warm salt water to clean the area and reduce bacteria.
- Avoid giving your child hard, sticky, or very hot or cold foods on that side of the mouth to prevent further damage or discomfort.
- Call your pediatric dentist to schedule a repair appointment. Most offices can see a child within a day or two for a lost filling.
- If the child experiences pain before the appointment, an age-appropriate dose of children’s acetaminophen or ibuprofen can help manage discomfort.
A filling can fall out because of normal wear, biting on something hard, new decay forming around the edges, or the natural loosening process as the baby tooth prepares to fall out. The dentist will evaluate whether the tooth needs a new filling, a crown for added strength, or whether it is close enough to falling out naturally that treatment is no longer necessary.
Do Fillings Fall Out When Baby Teeth Fall Out?
Yes, fillings fall out along with the baby tooth when the tooth falls out naturally. As the permanent tooth below pushes upward, it dissolves the roots of the baby tooth above it. The baby tooth loosens gradually and eventually comes out on its own, filling and all. The filling does not interfere with this natural process. Parents do not need to worry about the filling staying behind in the gum or affecting the permanent tooth’s eruption path.
In rare cases, a baby tooth with a large filling or crown may take slightly longer to loosen because the restoration adds weight and surface area. If a filled baby tooth seems stuck while the surrounding teeth have already fallen out, a quick visit to the dentist can confirm whether the tooth needs a little help or just more time.
How Can Parents Help Fillings Last Longer?
Parents can help fillings last longer by maintaining consistent oral hygiene habits, controlling sugar intake, scheduling regular dental visits, and protecting teeth from physical damage.
Brushing twice a day with fluoride toothpaste removes plaque that produces the acid responsible for decay around fillings. The ADA recommends a smear of fluoride toothpaste (the size of a grain of rice) for children under 3 and a pea-sized amount for children 3 to 6. Flossing once daily cleans between teeth where a toothbrush cannot reach, and these contact points are exactly where recurrent decay around fillings tends to start.
Preventing cavities from forming in the first place is even better than treating them. Diet plays a major role. Sticky, chewy candies like taffy and gummy bears can physically pull on fillings and dislodge them. Sugary drinks bathe the teeth in acid throughout the day. Encouraging water over juice or soda neutralizes acid and promotes saliva flow, which naturally protects enamel. Limiting snacking frequency also helps. Each time a child eats, bacteria produce acid for about 20 minutes afterward. Fewer snacking episodes mean fewer acid attacks.
Regular dental checkups every six months allow the dentist to monitor existing fillings and catch early signs of wear, cracking, or recurrent decay before they become bigger problems. Professional fluoride treatments strengthen the enamel surrounding fillings. Dental sealants on healthy molars prevent new cavities from forming in the grooves of the teeth. According to the CDC, sealants prevent 80 percent of cavities in back teeth for two years after application and continue to protect against 50 percent of cavities for up to four years. School-age children without sealants have almost three times more cavities than children with sealants.
For children who grind their teeth at night, a pediatric dentist may recommend a nightguard. Bruxism puts significant repetitive pressure on fillings and can cause them to crack or wear down prematurely. Protecting fillings from grinding forces extends their functional life considerably.
Frequently Asked Questions
Can Fillings Last 20 Years?
Fillings can last 20 years in adult permanent teeth with excellent care, but this timeline does not apply to baby teeth. Baby teeth fall out naturally between ages 6 and 13, so a filling in a baby tooth only needs to last until the tooth exfoliates. In permanent teeth, amalgam fillings have been documented to last 15 to 20 years or more. Composite fillings in permanent teeth can last 10 to 15 years with proper oral hygiene and regular dental visits.
Are White Fillings Safe for Children?
White (composite resin) fillings are safe for children. Composite resin has been used in pediatric dentistry for decades. The American Dental Association and the AAPD both recognize composite as a safe, effective, and durable restorative material for primary and permanent teeth. Modern composite formulations are BPA-free or contain such minimal trace amounts that they pose no measurable health risk. Composite has largely replaced amalgam as the standard filling material in children’s dentistry.
Do Dentists Fill Cavities Unnecessarily?
Reputable pediatric dentists do not fill cavities unnecessarily. A filling is recommended only when a cavity has broken through the enamel and formed a hole that the tooth cannot repair on its own. Very early-stage decay in the white-spot phase can sometimes be reversed with professional fluoride treatments and improved brushing habits. If you ever have questions about a recommended treatment, ask your dentist to show you the X-ray and explain what they see.
How Many Cavities Will a Dentist Fill at a Time?
The number of cavities a dentist fills at one time depends on the child’s age, behavior, attention span, and the location of the cavities. Some children do well having two or three small fillings completed in a single visit. Others, especially younger or more anxious children, may benefit from shorter appointments that address one or two cavities at a time. Nitrous oxide (laughing gas) can help children stay calm and comfortable during longer treatment sessions.
Is It Better to Not Get Fillings?
It is not better to skip fillings when a cavity has formed. An untreated cavity will continue to grow. It will not heal on its own. Without treatment, the decay eventually reaches the nerve, causing pain, infection, and potentially the loss of the tooth. The only situation where a dentist may choose not to fill a cavity is when the tooth is already very loose and close to falling out naturally, or when the decay is so minimal that remineralization therapy may reverse it.
Putting It All Together
Fillings in baby teeth last anywhere from 3 to 15 years depending on the material, but the most common composite fillings typically hold up for 5 to 7 years. The good news is that a filling does not need to last forever. It only needs to protect the tooth until the permanent tooth below is ready to take its place. Early treatment keeps the process simple and comfortable. Waiting turns a small filling into a bigger, more involved procedure.
The best way to protect your child’s fillings is consistent brushing, flossing, a low-sugar diet, and regular dental checkups every six months. Catching problems early keeps treatment simple, fast, and comfortable for your child.
At Cohen Family Smiles, our board-certified pediatric dentists provide gentle, kid-friendly care for children of all ages. If your child needs a filling or if you have questions about an existing one, call us at 914-245-2965 to schedule a visit.
