Child sucking his thumb
Dr Chris Darby

Dr Chris Darby

Thumb Sucking: The Dangers and How to Break the Habit

Thumb sucking is a calming behaviour that most children exhibit. Usually, thumb sucking falls away naturally, with children growing out of the habit. However, some kids will continue to suck their thumbs well past toddler-age. At this stage of growth of development, parents – and often dentists – will need to intervene to prevent this behaviour.

You may wonder why dentists are involved in this. Persistent thumb sucking can cause significant damage to the face, jaw and tooth development when it continues past the age of three to four. Given the large impact on overall oral health, dentists are generally more than happy to help parents with tips and tricks on overcoming the thumb sucking habit.

The Dangers

Here are some of the dangers you need to be aware of, and why you need to focus on helping your child break the thumb sucking habit.

Open Bite

An open bite is a form of tooth misalignment or malocclusion that is visible even when the mouth is closed. In this form, the top and bottom teeth are directed outwards, and the front teeth don’t touch the bottom teeth, even with a fully closed mouth. A dental intervention will be required to correct this bite.


In this configuration, only the front teeth are directed outward which creates an overbite. The top teeth cover them bottom teeth when the mouth closes, while the bottom teeth rest in the normal position. This can affect the shape of the smile and face, and in extreme cases, orthodontic treatments will be required.

Speech Difficulties

As thumb sucking affects the development of the key speaking muscles and areas, like the jaw, palate and the teeth, speech can be affected by the habit. The most common difficulties come in the form of impediments such as lisping, and an inability to produce hard consonant sounds like ‘T’ and ‘D’.

Skin Issues

Problems aren’t contained to the mouth and teeth. The habit can also affect the thumb, as the constant moisture can cause cracking, bleeding, callouses, infection and even a warped or ingrown thumbnail.

Breaking the Habit

Children continue to suck their thumbs for a variety of reasons, ranging from comfort to just plain old habit. The most appropriate method by which to break this habit is highly dependent on the age of the child.

However, one thing that does not work is aversion therapy. Putting chilli, or other unpleasant tastes on your child’s thumb will not work. It will probably just make your child upset and unhappy with you.

If no damage has been done to the pallet or the bite, you should consider the Thumb Guard. This is a thumb sucking abatement device by Medital. It was developed by an engineer who was struggling to get his daughter to stop sucking her thumb. It doesn’t stop children from sucking their thumb, it just makes it less comforting and reminds your child that they need to refrain from doing it.

The Thumb Guard needs to be worn all day and night, so if your child is school age just tell them to tell their friends they hurt their thumb. It comes in three sizes (Small, Medium, Large) and is perfect for all the subconscious thumb sucking because it breaks the oral vacuum with provides the comfort. Tests have shown it has a 90% success rate.

If you’re child only engages in this habit at night, you can bandage their elbow, so they can’t bend it to perform the action.

Of course, you can even rely on the power of persuasion. Don’t be afraid to tell a few white lies or some horror stories if you think it will work. Some things you could focus on include:

  • Appearance: Even young kids are surprisingly sensitive about their appearance. By telling them that the habit will affect the way their teeth and face look, it might be enough to scare them away from the habit.
  • Germs: Kids are very aware of and very fearful of germs. Tell them about all the dirty places their thumbs have been and why it’s not a very nice thing to put in their mouth.
  • Social Pressure: Explain that thumb sucking is only for young kids, and if they do it at kindergarten or school, they may get teased. You can also tell them about the possible speech impediments they could develop, and that could be more reason for other kids to pick on them.

This may seem like a harsh technique, and it won’t work with all children. No one knows their kids better than parents, and some kids will be able to hear this and respond to it without getting upset or anxious. You have to make that call.

With both techniques, you should keep them up for about a month, and studies show this is how long it takes for children to leave the habit behind for good.

If the habit has caused damage, in the form of narrowing the pallet, you can often kill two birds with one stone by having an expander fitted. This will prevent the thumb sucking, and undo the damage caused in the first place.

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