A few myths about cavities in baby teeth

Baby at dental check-up – baby’s head is in dentist’s lap knee-to-knee with a mom who is holding on.

Author: Dr. Dami Kim is a board-certified pediatric dentist. Before joining the WVU School of Dentistry as a full-time faculty, Dr. Kim worked in private practice for over 10 years in NJ and served families from all walks of life. 

As a pediatric dentist, I often hear some comments from parents and family members about why they believe the young patients have cavities on their baby teeth. 

  1. Cavities run in family genes.
  2. Some baby teeth already had cavities when they came into the mouth.
  3. My child’s teeth are weak and get cavities no matter what.

The good news is that none of the above is true and dental cavities are preventable diseases, even in baby teeth. For any teeth to develop cavities, two things need to be on the teeth: sugar and bacteria. The following explains where the sugar comes from.

Myth 1. Cavities run in family genes.

Most of the time, the reason for multiple members in one family to share the same dental problems is that they have a similar preference for choices of foods and similar habits of oral hygiene. When children are surrounded by certain types of foods, they learn to consume those foods as their daily source of nutrition. Of course, this comes with individual preference and that’s why siblings can have different dental experiences; one may choose chicken nuggets while another one prefers sweet pancakes. Oral hygiene habit is also a learned behavior. This is why it is important for all family members to make smart choices of foods and practice daily oral hygiene around the children.

Myth 2. Some baby teeth already had cavities when they erupted.

On occasions, parents notice some new baby teeth erupting already have cavities in them. This indicates that the baby is already having a source of sugar that is present in the mouth for a significant amount of time. Breast milk does not cause cavities on its own. However, when on-demand breastfeeding continues until the age to start baby foods during the day and if the teeth are not brushed before bedtime, the baby can still get cavities. The baby foods sitting on the teeth can cause the cavities more easily when the teeth are bathed in breast milk because it inhibits saliva from its anti-cavity actions. These cavities can form even on a small surface of teeth present in the mouth and this is why, sometimes, teeth look like they came in with cavities. The same is true for non-breastfed babies. However, additionally, the content in any feeding container (baby bottle, sippy cups, etc), anything other than water, such as formula or juice, can also develop cavities. These drinks contain sugar without the protective protein breastmilk has and even a very small amount of sugar can cause damage if it is present in the mouth for sufficient time for bacteria to metabolize the sugar. This is why watered down juice can still cause cavities. It is not the amount of sugar but the length of time in the mouth that matters in developing cavities.

Myth 3. Some teeth are weak and get cavities no matter what

There are some medical conditions that can cause the formation of the outer surface of teeth, called enamel, brittle, or inner surface, called dentin, thin. This happens, however, not very often and the people affected by them are a few. Even if this is true, the cavity formation always requires sugar. By reducing the amount and length of time of sugar consumption and cleaning the surface of the teeth, cavities are preventable.  

The bottom line is that there is always something that we, as parents and family members, can do to keep the white pearls healthy and beautiful. These are some of many things we can try at home to improve every one’s oral health.

  1. Find non-nutritional alternatives to soothe babies to fall asleep at night. Try to wean off the babies from on-demand breastfeeding or any other feeding as soon as possible as they develop new teeth or close to the time to get teeth (On average, the first tooth erupts around 6 months). You may take some transitional steps such as putting water instead of milk in the bottle or switch to a pacifier instead. However, for normal tooth development, the alternatives need to be also weaned off eventually.
  2. Brush the teeth daily, especially at bedtime, as soon as you can see the white in the mouth.
  3. Minimize the frequency of snacking and feed more during mealtime. Constant exposing foods throughout the day keep the mouth a harsh environment for the teeth. The mouth needs breaks so the saliva and tongue can keep the teeth clean. 
  4. Take care of yourself first! Keeping your teeth healthy results in fewer bacteria to pass to your babies. This, in turn, results in less chance for the babies to develop cavities now and in the future!
  5. Visit your local pediatric or family dentist as soon as the first tooth comes in and establish a dental home for regular check-ups and fluoride treatment.


1. https://www.aapd.org/resources/parent/

2. Pediatric Dentistry Infancy through Adolescence 5th Edition by Casamassimo, Fields, McTique and Nowak