Cavities In Kids – 7 Surprising Reasons

cavities in kids
Cavities in kids

Cavities in kids are the most commonly encountered dental problem. They develop from the destruction of tooth enamel by mouth bacteria. The plaque bacteria produce acid from simple sugars and cause enamel demineralization.

A dull white spot along the gum line shows the early sign of tooth decay. As it progresses a brown or black discoloration appears along the gum line and later breaks down and forms a cavity. Because dental enamel is thin in milk teeth, cavities can become painful quickly.

Before jumping on to the reasons that lead to cavities in kids it’s important to know this:

Why is it so important to keep milk teeth healthy when they have to fall out anyway and be replaced by permanent teeth?

First, milk teeth retain the place for the permanent teeth and if they are lost early on they can cause crowding in adult teeth. Second, if cavities in baby teeth are left treated, the infection may come out in the bone and can damage the permanent teeth buds under the milk teeth.

Feeding bottles and nursing bottle tooth decay

Nursing bottle caries occurs predominantly due to the feeding bottles where kids go to bed with a bottle or keep a bottle for a long period in their mouth. The destruction of baby teeth occurs because of the prolonged and frequent exposure to formula, milk, or juices.  This type of dental caries is also known as baby bottle tooth decay.

It affects the upper front teeth and the biting surfaces of back teeth due to the pooling of milk around these teeth. However, saliva released from the nearby salivary glands and tongue positioned over the lower front teeth spares them from getting cavities.

Transfer of germs from mother to baby

Tooth decay in kids can occur anytime after the first pair of teeth comes into the mouth. A child’s mouth is sterile at birth. The germs that cause teeth decay can transfer from mothers’ or caretakers’ mouths through saliva. For instance, kids often throw their feeding spoons or pacifier on the floor and the mother puts them in her mouth to clean them and gives it back to the baby.

These bacteria convert fermentable carbohydrates in milk, formula, and juices to acids that destroy the outer enamel of baby teeth.

Cavities in children from drinking non-fluoride water

Fluoride helps protect against tooth decay. The children living in non-fluoridated areas or the ones who drink spring water are more likely to have cavities than the ones who consume fluoride either through water or food. Moreover, Fluoride works topically to strengthen the tooth enamel and is therefore never given before 6 months of age.

Poor oral hygiene and more cavities in kids back teeth

Good oral hygiene plays an important role in keeping cavities in check. Plaque and bacterial colonies accumulate more on the back teeth. The presence of pits and grooves on their chewing surface and improper and irregular cleaning and flossing creates a suitable environment for cavities to develop.

Dry mouth and cavities in kids

Saliva plays an important role in keeping the mouth moist all the time. It also washes away bacteria and fungi from the mouth and contains antibacterial enzymes and minerals. Therefore, it protects your child from cavities. Reduced salivary flow flourishes bacterial growth on the teeth and provides a favorable environment for the infection to develop.  

First, the most frequent cause of dry mouth among kids is dehydration, and drinking enough water prevents them from dehydration.

Second, frequent intake of caffeinated drinks like cola-cola also decreases saliva flow and works as a double edge sword. Acid formation from high sugar content in these drinks and diminished saliva paves the way for the cavities.

Mouth breathing is next on the list. Breathing from the mouth causes dryness of oral structures and predisposes a child to tooth decay.

Children with a narrow upper jaw and forward-positioned upper teeth often suffer from mouth breathing. The forward positioning of teeth makes it hard for the child to close his mouth and allows him to breathe from the mouth.

Moreover, a nasal obstruction from adenoids, deviated nasal septum or nasal polyps also prevents the child from breathing from the nose.

Encourage your child to breathe from the nose and if you notice it’s difficult for him/her to breathe, consult a GP.

More sugar intake and frequent snacking are associated with more cavities in kids

The foods and drinks containing fermentable carbohydrates, for instance, lactose in milk, fructose and glucose in fruit juices, and glucose in refined foods cause tooth decay in kids. All refined foods such as cereals, pasta, and white bread are stripped of fiber and are high in simple sugars that are metabolized by mouth bacteria into acid.

Research shows that an intake of free sugars of ≤10% of energy is associated with a lower risk of dental caries, but this threshold did not eliminate dental caries. WHO recommends a reduced intake of free sugars, and that in both children and adults the intake of free sugars should not exceed 10% of total energy intake. 

It is surprising to know that it’s not the quantity of sugar that a child consumes in a day matter most but its frequency of eating that has the most impact. For example, drinking a juice in a sippy cup for hours causes hours of sugar exposure to the teeth. However, drinking the same amount of juice with a meal reduces the overall time of sugar your child’s teeth are exposed to. Therefore, the longer duration of sugar exposure to teeth directly relates to the episodes of acid formation and hence enamel demineralization.

Enamel or dentin defects and cavities in toddlers

Enamel is a thin, hard, outer layer of teeth, and beneath enamel lies thick, resilient dentin. Certain rare genetic diseases like enamel and dentin hypoplasia or hypomineralization defects present with defective enamel and dentin respectively in milk and permanent teeth.

The defective enamel chips off early in life exposing the dentin to saliva and cavity formation in enamel defects. On the other hand, in dentin disorders enamel is however normal, but the irregular and non-resilient dentin cannot support enamel and the enamel soon breaks off.

See a dentist if you see more than two missing teeth or the shape of teeth seems unusual to you in your child.

What you can do about cavities in kids to prevent it?

Proper care and and following below measures can save child’s milk teeth until their permanent teeth erupts:

Do not allow your child to sip on milk, formula, or juices throughout the day.

Avoid nocturnal bottle feeding after the first teeth appear in the mouth. Put your child to bed with a bottle containing water if necessary.

Clean the mouth with a clean cloth twice daily in infants.

Start weaning the bottle after child’s first birthday. Introduce training sippy spoutless cups at 6-7 months of age when they start solids.

Book your first child’s appointment with your dentist when he/she turns one. Kids who are at high risk of getting tooth decay require fluoride varnishes. Talk to your dentist if you see two or more cavities in your child’s mouth.

Develop a habit of brushing teeth twice a day in toddlers of 3 years or above with a pea-size fluoridated toothpaste on a soft bristle toothbrush. Adults should supervise their children while they brush their teeth to ensure proper cleaning.


Tooth decay in kids affects children from the time the first tooth appears in the mouth till the last milk tooth falls. It is common to find decay in kids who are put to bed with a bottle. Mouth bacteria convert the lactose in milk and fructose in juices to acid and cause tooth decay. Proper care and weaning off the bottle early on can prevent milk teeth from decaying.

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