What Is a Cavity in Milk Teeth?
A cavity in milk teeth is a small hole in a baby tooth caused by tooth decay. It forms when bacteria and sugar wear away the hard outer layer of the tooth.
Milk teeth are the first set of 20 teeth a child gets. You may also hear them called baby teeth or primary teeth. They usually start coming in around 6 months of age and stay in the mouth until the adult teeth are ready to replace them.
Cavities in baby teeth are extremely common. Research demonstrates that dental caries is among the most widespread chronic diseases affecting children across the globe.[5][9] When decay starts very early and affects several teeth, dentists call it early childhood caries. A common form is baby bottle tooth decay.
Some parents assume baby teeth do not matter because they fall out. That is not the case. Healthy baby teeth help a child chew, speak, and smile. They also hold space so the permanent teeth can grow in straight. Losing a milk tooth too early can crowd the surrounding teeth and may lead to orthodontic treatment later. Protecting milk teeth protects a child's oral health for years to come.
What Causes Cavities in Baby Teeth?
Cavities in baby teeth happen when mouth bacteria feed on sugar and make acid. That acid slowly breaks down tooth enamel, the hard surface of the tooth. Over time, this creates a cavity.
Sugar, Bacteria, and Diet
Every time a child eats or drinks something with sugar, the bacteria in the mouth make acid for a short time. Frequent snacking and sipping sugary drinks keep that acid attack going. This is why how often a child eats sugar matters as much as how much.
Sticky foods, candy, and sweetened drinks raise the risk. Water and plain foods do not feed decay the same way. Wiping the gums and brushing with a small smear of fluoride toothpaste helps remove the bacteria and sugar that cause tooth decay.
Bottles and Feeding Habits
Baby bottle tooth decay happens when a baby's teeth sit in contact with milk, formula, or juice for long periods. This often occurs when a child falls asleep with a bottle or sips from one all day.[11]
The front baby teeth are usually affected first. To lower the risk, avoid putting a child to bed with a bottle of anything except water, and offer a cup instead of a bottle as the first birthday nears.
Other Risk Factors
Some children face a higher risk for cavities in milk teeth for reasons beyond diet. Defects in how the enamel formed before birth can leave milk teeth softer and easier to decay. Research has linked deciduous teeth hypomineralisation to certain perinatal risk factors around the time of birth.[3]
Nutrition may also play a part. A systematic review examined the role of vitamin D in caries risk in children's deciduous teeth, suggesting low vitamin D may be associated with more decay, though more study is needed.[4] Children with special health care needs can also have a different risk profile; one study compared caries risk factors in children with Down syndrome and children without special health needs.[7] A child's individual risk is best judged by a pediatric dentist.
Signs a Child Has a Cavity
The first sign is often a chalky white spot near the gumline, which means enamel is losing minerals. As decay grows, the tooth appears to have brown or black spots or a visible hole.
What Parents May Notice
Early cavities in baby teeth often cause no pain at all. That is one reason they are easy to miss. As the cavity gets deeper, a child may complain of sensitivity to hot, cold, or sweet foods.
Later signs include toothache, trouble chewing, swelling near a tooth, or a tooth that looks darker than the surrounding teeth. A young child may simply become fussy at meals or avoid chewing on one side.
How Cavities Are Diagnosed
A dentist diagnoses a cavity by looking at and feeling the child's teeth, often with dental X-rays to check between teeth and below the surface. Early detection lets the dentist treat a small spot before it turns into a larger problem.
Several tools support early caries diagnosis beyond the eye alone. A systematic review and meta-analysis evaluated detection methods for finding early caries, helping dentists catch decay sooner.[8] Regular dental check ups give the dentist the chance to track small changes over time.
When to Seek Care
Call a dentist if you see a white, brown, or black spot, a hole, or any swelling, or if your child has tooth pain. The American Academy of Pediatric Dentistry recommends a first dental visit by the first birthday or when the first tooth comes in.[11] Early visits help keep milk teeth healthy and catch problems while they are small.
Treating Cavities in Baby Teeth
Treatment depends on how deep the decay has gone. Early decay may be slowed or reversed with fluoride, while a true cavity needs a filling, a crown, or pulp therapy to save the tooth.
Fluoride and Early Treatment
When decay is caught at the white-spot stage, the tooth can sometimes heal before a hole forms. Dentists may apply fluoride varnish and recommend brushing with fluoride toothpaste to add minerals back to the enamel.
Sealants are another preventive option. A Cochrane review looked at sealants for preventing dental caries in primary teeth, supporting their use to protect the chewing surfaces of back baby teeth.[6]
Fillings and Crowns
Once a cavity has formed a hole, the dentist removes the decay and fills the space. Fillings restore the tooth's shape and stop the decay from spreading to surrounding teeth.
When a cavity is large and a filling would not hold, the dentist may place a crown that covers the whole tooth. Crowns are common on back baby teeth that take heavy chewing force.
Pulp Therapy for Deep Decay
If decay reaches the soft inner tissue, called the pulp, the tooth needs pulp therapy to be saved. Treatment guidance on vital pulp therapies in primary teeth helps dentists decide how to manage a tooth where the pulp is still healthy.[1]
When the pulp is already infected or dying, a different approach is used. A systematic review and meta-analysis of nonvital pulp therapy for primary teeth supports treatments that keep a baby tooth in place when possible.[10] Keeping the tooth helps preserve space for the adult teeth.
When a Tooth Must Be Removed
If a tooth is too damaged to repair, the dentist may remove it. Because a milk tooth holds space for a permanent tooth, the dentist may place a space maintainer so the surrounding teeth do not drift. This can lower the chance of crowding and future orthodontic treatment.
Recovery and Aftercare
Recovery from a filling or crown is usually quick, and most children return to normal eating within a day. Numbness from local anesthetic wears off in a few hours, so watch that your child does not bite the cheek or lip.
After a filling, mild soreness or sensitivity to cold is common and typically fades within a few days. After pulp therapy or an extraction, the dentist may suggest soft foods for a short time and a children's pain reliever as directed. Results vary by child and by how deep the decay was.
Aftercare is mostly about prevention. Brush twice a day with a small amount of fluoride toothpaste, limit sugary drinks, and keep regular dental check ups. Good daily habits protect both the treated tooth and the surrounding teeth, and they set the stage for healthy adult teeth.
What Treatment Costs
The cost of treating a cavity in milk teeth depends on the treatment, the tooth, and your location. A simple fluoride treatment costs far less than a crown or pulp therapy.
As a general guide, fluoride varnish often runs in the range of about $25 to $75 per visit, a filling roughly $90 to $300, and a crown or pulp therapy several hundred dollars per tooth. These are estimates only. Costs vary by location, provider, and case complexity.
Many dental insurance plans and public programs for children cover a large share of preventive and basic restorative care, including check ups and fillings. Ask the dental office what your plan covers and whether they offer payment plans. Preventing cavities through daily care and early detection is usually the lowest-cost path of all.
Pediatric Dentist vs. General Dentist
A general dentist can treat many cavities in baby teeth, but a pediatric dentist has extra training focused on children. They are often the better choice for very young children, for early childhood caries affecting several teeth, or for a child who is anxious or has special health care needs.
Pediatric dentists also manage behavior and comfort in ways suited to small children, and they plan ahead for how milk teeth guide the adult teeth. The American Dental Association offers parent-friendly guidance on children's oral health that can help you decide.[12]
If your child has deep decay, needs pulp therapy, or has a medical condition that raises caries risk, a specialist visit is worth considering. The goal is the same in every case: keep milk teeth and healthy teeth working until the permanent teeth arrive.
Find a Pediatric Dentist
If your child has a cavity, or you want to prevent one, a pediatric dentist can help build a plan for healthy baby teeth and lasting oral health. Learn more on the pediatric-dentistry page and find a specialist near you for an evaluation and regular dental check ups.
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