Children’s primary teeth begin to erupt around six to eight months, and continue until they are about two years old. Their permanent teeth will start to erupt around six or seven years old, and continue until as late as 25 years old¹. Often, parents will not be concerned about the cavities that their children have in their primary teeth knowing that their child’s permanent teeth will eventually erupt. There are numerous reasons to prevent cavities even in the primary dentition – if cavities aren’t prevented, they can lead to serious trouble down the road. In this post we will explore why we should prevent cavities in the primary dentition, as well as how we can do it.
How Do Children Get Cavities?
Cavities, or ‘caries,’ is a process where decay forms from the acids produced by bacteria when we eat sugar. Cavities are caused by a bacteria called S. mutans (among others). There are numerous factors that cause cavities (which are talked about in the link above), though there are some that are particularly relevant to children.

Let’s review the four factors that contribute to cavities – bacterial load, food (sugars), saliva flow, and frequency of brushing. We are going to hit on all four of these in respect to children. When a child is born, they are not born with the bacteria that commonly cause a cavity. Studies show that there is a period known as the ‘window of infectivity’ between 19 and 33 months of age when children acquire the bacteria that causes cavities (cariogenic organisms). This was first established in 1993 by a researcher named Caufield, but has since been reinforced by multiple studies. Where it gets interesting, though, is how the child receives these bacteria. Most commonly, the main perpetrator is the child’s own mother². In fact, ‘child-nurturing habits which facilitate saliva transfer from adults to the children, such as sharing of food and utensils, and habits which involve close contact, such as breast-feeding, kissing and sleeping beside the mother, were also found significantly associated with colonization of the bacteria².’
So What Foods Are Contributing To My Kids Cavities?
We know that cavities are caused by bacteria that fuel themselves off sugars or carbohydrates, but what many parents don’t understand is there are plenty of foods that contain hidden sugars. For instance, in breast milk alone, 17g of sugar is found in one cup according to the USDA (compare that to a cup of soda at around 25g of sugar). There’s also fruit juice, which contains about 23g of sugar per cup, too. All of this information doesn’t take into effect the acidity of the beverages, which also plays a part in the demineralizing factors of the teeth.
‘Children who consumed sweetened beverages in their baby bottles were four times more likely to have MS (mutans steptococci, the bacteria that causes cavities) than were children who consumed only milk’
McDonald and Avery’s Dentistry for the Child and Adolescent, 10th Edition

More and more studies are showing that diet is a primary factor in how children (and adults!) are contributing to their cavities. It was found in an extensive (and widely referenced) study by Gustaffson et al that a group of patients whose diet was low in fat, low in carbs, and free of sugar had low caries activity. This study went on to conclude that the frequency of when the sugars were consumed seemed to be the main factor (such as snacking between meals)³.
What Does Saliva Have To Do With Anything?
Saliva has many uses – it breaks up food, lubricates our mouth, and alkalizes the pH of our mouth when we eat. Discussed in detail in last week’s post about brushing, this helps our teeth stay ‘mineralized’ instead of leaching calcium and other minerals caused by acidic foods. I haven’t met a child yet that doesn’t slobber – so if you’re more interested about how saliva affects our teeth check out the post above.

Why Should I Prevent Cavities In My Child? Won’t They Have New Permanent Teeth?
For 2015–2016, prevalence of total caries (untreated and treated) was 45.8% and untreated caries was 13.0% among youth aged 2–19 years according to the CDC⁴. That’s a pretty large amount of cavities for children – and the problem isn’t going anywhere soon. So why do we need to be concerned? Let’s review.
First and foremost, cavities can develop the deeper they move into the tooth – resulting in inflammation of the bone that holds them and leading to infection. Abscess can develop, or worse, a spread of the infection into fascial tissue. The obvious problem here is the pain it can cause your child, though more seriously (although rarely), a systemic infection. It’s more obvious that we want to prevent cavities to prevent these issues.
But what about the underlying issues that cavities can cause? It’s been known that, in children who experience early childhood caries of their primary teeth, they are at a greater chance to develop caries as an older adult (with their permanent teeth)⁵. In the study cited, children who had early childhood caries, regardless if they were treated or not, still experienced a higher risk for developing permanent caries in their first permanent molars. There’s even studies that show cavities on primary teeth contribute to defects in the enamel of their successors – ‘In one report, if the primary tooth developed caries, the successor was twice as likely to demonstrate a circumscribed enamel defect. In addition, if the primary tooth was extracted for any reason other than trauma, then the prevalence of a demarcated enamel defect increased fivefold⁶.
There’s one more reason we should prevent cavities in our children – primary teeth are there to hold space for the permanent teeth. If we lose too many of our primary teeth, our permanent teeth may not have the proper amount of space to erupt in the correct sequence. This can cause functional problems throughout their adult life, as well as esthetic problems. If a child loses any of their back teeth too soon, it’s important to let your dentist know!
How Can I Prevent The Cavities In My Child?
The biggest advice we give to new parents, and perhaps one of the most important, is to send your child to see the dentist as soon as their first tooth erupts (around six months, if you’ve been paying attention). This will allow the child to normalize what being at a dentist feels like, as well as allow the dentist to begin charting their progress. The sooner the child feels comfortable with the dentist, the easier it will be to prevent and treat any issues in the future.
It’s not that easy, though, there’s multiple methods we can use to reduce the chances they get cavities at all. To begin, we’ve already touched on diet. Stay away from sugary beverages and leaving a bottle of milk for them at night – diet is one of the main contributors of cavities. That being said, foods like cheese can actually help the oral environment, and raw fruits and vegetables won’t contribute to caries as much. Avoid between-meal snacks, too, especially those that are sugary. Remember, it’s the frequency of eating these foods that plays a larger role in developing cavities.
Don’t forget about how the child get’s the bacteria that causes these cavities – we now know it’s mother’s that most commonly deliver them to their child. Avoid sharing drinks, kissing on the mouth, or sharing spoons or toothbrushes.
Lastly, it’s important the child is brushing their teeth with a fluoridated toothpaste. Fluoridated toothpaste has been accredited with the dramatic decline in caries of the last decade of the twentieth century⁷. For children below the age of three, just use a ‘smear’ or ‘rice-size’ amount of toothpaste. This can be done with a rag or towel, if needed. For children above the age of three, use a ‘pea-size’ amount of toothpaste⁸. It cannot be stressed the impact of fluoride on oral health, and its use will be discussed in later posts.

To Summarize:
- Children’s primary teeth are just as important as their permanent successors
- Bacteria, saliva, sugars, and brushing all play a role in cavities
- Mother’s commonly give their children the bacteria that cause cavities
- Fruit juices and milk are huge contributors to cavities
- The frequency of snacking plays a larger role than the quantity of snacking
- You may have more cavities as an adult if you have them as a child
- Your child should see the dentist as soon as they have their first tooth
- Use a fluoridated toothpaste for your child
References:
¹Dean, A., J. (2015). McDonald and Avery’s Dentistry for the Child and Adolescent, 10th Edition. [VitalSource Bookshelf 9.4.0]. Retrieved from vbk://9780323287463
²Damle, S. G., Yadav, R., Garg, S., Dhindsa, A., Beniwal, V., Loomba, A., & Chatterjee, S. (2016). Transmission of mutans streptococci in mother-child pairs. The Indian journal of medical research, 144(2), 264–270. https://doi.org/10.4103/0971-5916.195042
³GUSTAFSSON, B. E., QUENSEL, C. E., LANKE, L. S., LUNDQVIST, C., GRAHNEN, H., BONOW, B. E., & KRASSE, B. (1954). The Vipeholm dental caries study; the effect of different levels of carbohydrate intake on caries activity in 436 individuals observed for five years. Acta Odontologica Scandinavica, 11(3–4), 232–264. https://doi.org/10.3109/00016355308993925
⁴Fleming E, Afful J. Prevalence of total and untreated dental caries among youth: United States, 2015–2016. NCHS Data Brief, no 307. Hyattsville, MD: National Center for Health Statistics. 2018.
⁵Songur, F., Simsek Derelioglu, S., Yilmaz, S., & Koşan, Z. (2019). Assessing the Impact of Early Childhood Caries on the Development of First Permanent Molar Decays. Frontiers in public health, 7, 186. https://doi.org/10.3389/fpubh.2019.00186
⁶Chi, A., Neville, B., Damm, D., Allen, C. (052015). Oral and Maxillofacial Pathology, 4th Edition. [VitalSource Bookshelf 9.4.0]. Retrieved from vbk://9781455770526
⁷Colak, H., Dülgergil, C. T., Dalli, M., & Hamidi, M. M. (2013). Early childhood caries update: A review of causes, diagnoses, and treatments. Journal of natural science, biology, and medicine, 4(1), 29–38. https://doi.org/10.4103/0976-9668.107257
⁸American Academy of Pediatric Dentistry (2015/2016). Policy on Early Childhood Caries (ECC): Classifications, Consequences, and Preventive Strategies. American Academy of Pediatric Dentistry Clinical Guidelines, 37 (6), 50-52.
Liability Statement:
The medical advice given in this blog should only be utilized by a medical professional who has received a medical degree. I am not responsible for the medical advice given in this blog and each case should be reviewed extensively with sources outside my blog. This blog is for education purposes only and is not meant as a substitute for an academic institution.