October 11, 2018


Why some kids are more prone to dental decay

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Up to 14% of toddlers have “hypomineralised second primary molars” (HSPM), where the enamel (outer layer) of the second baby molars doesn’t develop properly.

Mihiri Silva, Murdoch Children’s Research Institute; Katrina Scurrah, University of Melbourne, and Nicky Kilpatrick, Royal Children’s Hospital

A quarter of children have dental decay by the time they start school. This occurs when bacteria in the mouth break down sugar to produce acid, which attacks and dissolves the teeth.

Avoiding sugary food and drinks and brushing regularly with an age-appropriate fluoridated toothpaste remain the best ways to ensure children have healthy teeth. But despite parents’ best efforts, some children’s teeth are inherently weak and decay more easily.

Historically this was thought only to affect a very small minority (0.1%) of people who had rare genetic conditions such as amelogenesis imperfecta (enamel malformation).

But more recent Australian studies have reported that up to 14% of pre-schoolers may have “hypomineralised second primary molars” (HSPM), where the enamel (outer layer) of the second baby molars doesn’t develop properly, making them weak and prone to damage.

The second primary molars (marked in purple) are the back ‘baby’ or ‘milk’ teeth.

What it means for kids

The teeth of children with hypomineralised second primary molars may have white or yellow patches with rough areas where the weak enamel has broken off.

The teeth can be so weak that they’re unable to cope with the demands of chewing and break down soon after they come through the gums.

These teeth are often highly sensitive and children may avoid brushing them because they hurt. Such sensitivity, combined with the weak enamel, means dental decay occurs more readily.

Read more:
How to (gently) get your child to brush their teeth

Providing dental care for children with these teeth is challenging, as the usual anaesthetic agents to numb teeth are less effective, and teeth often hurt during treatment.

The usual filling materials, which work by sticking to the enamel, don’t last as long because of the poor enamel quality, so these children need to have dental treatment more often.

All of this has been shown to lead to higher rates of dental anxiety and phobia.

The bad news doesn’t end there. If the baby teeth are affected, the adult teeth are also more likely to be affected.


Tooth enamel is formed long before the teeth come through the gums. The baby molars start to form halfway through pregnancy, and are essentially completely formed by birth.

Unlike skin and bone, tooth enamel can’t naturally heal, so any damage would still be present when the second primary molars erupt, at around two years of age.

Despite the recommendation for children to have a dental checkup by the age of two, only one in three children has seen a dentist by age four. Defective teeth are sometimes not noticed until they break down and become infected. In such cases, they may need to be removed.

Read more:
Child tooth decay is on the rise, but few are brushing their teeth enough or seeing the dentist

A recent study of twin children found that the causes may not be genetic, but rather due to something that happens during pregnancy or birth. Hypomineralisation of second primary molars has been linked to maternal illness, smoking and alcohol use in pregnancy, and research is ongoing to clarify these links.


Conditions that weaken enamel mean that while a healthy diet and good brushing help, additional precautions are needed.

Dentists can help detect signs of weak teeth before they break down. They can help protect these teeth using seals or fillings that cover weak parts.

In badly affected teeth, this window of time is narrow, so it’s important to have regular dental visits, starting as early as 12 months of age, or when the teeth first come through.

Read more:
Bad teeth? Here’s when you can and can’t blame your parents

The Conversation

Mihiri Silva, Paediatric dentist and PhD candidate, Murdoch Children’s Research Institute; Katrina Scurrah, Senior Research Fellow (Biostatistician), University of Melbourne, and Nicky Kilpatrick, Associate Professor and Paediatric Dentist, Royal Children’s Hospital

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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  • This was a very informative article.


  • Wow what a great read thanks for all the useful information


  • I never realised that this could happen. My boys didn’t start going to the dentist until they started school. I’m glad to say they had no problems with their teeth but I’ll definitely be passing this on to my boys so they can make sure their kids go to a dentist much sooner.


  • My almost 4 year old niece has very damaged teeth, including fillings. It’s from poor hygiene and night breastfeeding (extended BF beyond 2 years)


  • I always take kids for regular checkups as I have had lots of problems when I was younger


  • I have a friend who’s 4 yo has just had to big molars pulled out. I thought it was because he wasn’t brushing properly and eating too much crap. Seems I may be wrong. The tooth fairy paid for the pulled out teeth, which isn’t right cos she doesn’t want faulty teeth ????

    • If that’s what the parents decided to do to help their child with the fact his/her teeth were being pulled out then I don’t see the issue. If it was my child and they had to have teeth pulled I would still say the tooth fairy is coming to collect them. If it was due to lack of looking after them, then it’s the parents responsibility still at that age to ensure their child is brushing their teeth properly and going over them to make sure after the child has finished brushing. I would use it as an opportunity though to explain to the child that if they don’t look after their teeth and they go yucky, then the tooth fairy will only give you less for a tooth than one that is nice and healthy


  • Unfortunately a lot of parents are hesitant to take young children to the dentist. They are sure they will be scared of the dentist and the financial gap in account can be horrific. It would be an excellent idea if dentists had a plan where children went at a much younger age and the dentist just looked in their mouths with the mirror and touched a few teeth without having to do anything or much for just 5 minutes or less to get the child used to having to open their mouth – not just to say aahh for a Dr. They could make a small introductory charge and it would be very beneficial to children.

    • We have this Child Dental Benefits Schedule. The Child Dental Benefits Schedule (CDBS) is a scheme run by Medicare that provides eligible children up to $1,000 over 2 calendar years to pay for a range of dental services. It’s aimed at families who are already receiving other benefits, such as Family Tax Benefit A payments.
      If your child is eligible, the CDBS will cover dental services including examinations, routine cleaning, repairing cracked teeth, fillings and root canals. It doesn’t cover orthodontic treatment (such as braces to straighten crooked teeth), any dental work that needs to be done in hospital, or cosmetic dental procedures (such as replacing missing teeth).


  • My teeth were weak as a toddler because of antibiotics. Thankfully now they aren’t as bad, but I use to have at least 2 fillings every time I went to the dentist, which was twice a year. Didn’t matter how often I brushed.


  • My son at age 5 had 2 molars broken off by the root. He needed to have them removed under narcosis. Now at age 13 his teeth are quite good, but I had all molars sealed.
    My 8 year old foster daughter had a very poor diet and very bad care till she was 3,5 yrs old, at which time she was removed from her parents. At age 4 she had 10 teeth removed and got 2 crowns placed. With a healthy diet and good dental care, her teeth at age 8 are good & healthy.
    I took my kids to the dentist before they turned 1 and we go every half year.


  • Worrying to think it happens so young


  • My 3 year son is very fond of chocolates. He love to eat chocolate but as we know that more choco become the reason of dental problem, same thing happens with my son. I am looking for a frankly nature doctor who can treat my son properly. When I visit at the clinic, I am assured that I choose the best place for my son treatment. The doctor was very friendly. He become my son’s friend. I am very happy with them.

    Read More about :- http://evedentalcentre.com.au/dentist-clyde/


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