How Thumb-Sucking Affects Dental Health

Dr. Christopher Li Etobicoke - Li Family Dental

By Dr. Christopher Li

October 22, 2023

children's teeth, dental health, dental issues, oral health, thumb-sucking

The sight of a baby or small child sucking his or her thumb is not uncommon. Thumb-sucking is a natural behaviour that many young children use to help soothe themselves, but that doesn’t mean there can’t be negative side effects. In some cases, there may be psychological effects that can carry into later childhood, but there are also potential dental issues that can develop if a child sucks their thumb for a prolonged period of time. Here‘s how thumb-sucking affects dental health if it carries on for too long.

How Thumb-Sucking Affects Dental Health



An overbite is one of the issues that can occur with prolonged thumb-sucking. A child can have a horizontal overbite or a vertical overbite. A horizontal overbite is when the upper front teeth protrude over the lower front teeth significantly in a horizontal fashion, causing a greater distance between the upper and lower jaws. With a vertical overbite, the upper front teeth overlap the lower front teeth vertically. Overbites can be worrisome because there is an increased risk of trauma to the upper front teeth, and a child may have difficulty chewing properly or speaking clearly. There are also aesthetic concerns associated with having a pronounced overbite.



Malocclusion is a misalignment or improper positioning of the teeth when the jaws are closed together. Basically, the upper and lower teeth don’t fit together properly when the child is biting or chewing. Naturally, this can cause issues when chewing food:  it can create spaces where there shouldn’t be any, cause overcrowding, or affect speech.

Speech Problems


If a child ends up with dental misalignment caused by thumb-sucking, it can affect the proper positioning of the tongue and lips during speech, which may lead to difficulties when forming certain sounds. There may also be issues with a condition known as tongue-thrusting, where the tongue pushes forward against the front teeth during speech. Some children may also develop problems with articulation, lisping, vowel distortions, issues with resonance, or breath control during speech.

Issues With The Palate


There are also a handful of different palate changes that can happen as a result of excessive thumb-sucking. One is narrowing of the palate, which can cause the maxillary arch to become more V-shaped rather than U-shaped, leading to dental misalignment. Thumb-sucking can also create a high palate, which is when the roof of the mouth is elevated, and the arch is more pronounced. The posture of the tongue can also be affected if the thumb is occupying the space where the tongue typically rests against the palate.

Problems With Baby Teeth And Permanent Teeth


Many parents are under the impression that there are no issues with baby teeth and thumb-sucking since those teeth are only around for a short period of time. This is partially true, but vigorous thumb-sucking that persists throughout the life of the baby teeth can still have negative effects on the jaws and palate that can cause issues moving forward. These jaw and palate issues can also affect permanent teeth when they finally come in.

When Do Problems Usually Start?


Childhood thumb-sucking is usually not an issue during infancy and the toddler years when there are no teeth or they’re just starting to come in. And there’s no set age when real problems start happening, but it’s safe to say that the longer the thumb-sucking habit lasts, the higher the chances of dental issues becoming a reality.

Not all children will have the same issues, either. The natural shape and spacing of the teeth, how frequently a child sucks his or her thumb, and how much force is applied during thumb-sucking all play a role in what kind of dental issues will occur, if any. The way a child sucks their thumb is also a factor in whether or not dental issues will occur, as the location and placement of the thumb can make a difference.

While these guidelines are vague, it’s important to note that children who continue to suck their thumb after the age of five have a much higher chance of developing bite issues than children who give it up at an earlier age. 

For Most Children Thumb-Sucking Is Temporary


If you’re a parent who is experiencing any concern or anxiety about your child’s thumb-sucking and possible dental impacts, keep in mind that most children will grow out of it naturally before any problems occur. As children get older and they encounter other kids, there is often a natural type of peer pressure that makes them want to leave their habit behind and be like the other kids.

The best thing to do is remain aware of the situation and do your best to support your child when the time comes to abandon their thumb-sucking habit. Also, encouraging them to develop a strong dental hygiene routine will make them aware that their oral health is important, which may make it easier to get them to stop sucking their thumb when the time comes. 

Useful Prevention Tips


If you’d like to be more proactive and look for ways to prevent your child from sucking his or her thumb, there are several things you can try that have been shown to be successful. Here are some effective ideas:

Ignoring the behaviour completely:  If your child’s thumb-sucking seems to become more persistent the more you pay attention to it, then maybe ignoring it will produce some positive results.

Positive reinforcement:  You can praise them when they consciously take their thumb out of their mouth or even create a system where they can take part and get small rewards like stickers in a notebook.

Manage common triggers:  Some common triggers that may initiate thumb-sucking include when the child is tired, hungry, bored, or anxious. If you notice a pattern, try introducing an activity that makes them use their hands instead.

Gentle reminders:  If your child wants to stop sucking their thumb, gently reminding them in the moment may help them become more conscious about it moving forward.

Thumb shields:  Soft plastic or fabric thumb guards can act as a physical barrier to prevent them from sucking their thumb, especially if they do it while sleeping.

Asking your dentist for help:  Sometimes, hearing straight from the dentist how sucking their thumb can affect their dental health will have a greater impact on a child than hearing it from a parent.

For more information on thumb-sucking or other childhood dental questions, give us a call at 416-232-2033 or request an appointment by clicking here .

Dr. Christopher Li

About the author

Doctor Christopher Li, DDS
Dr. Chris, as he is affectionately known, is a licensed dentist with over 20 years experience. His caring personality makes even the most tentative person at ease. Patients are constantly commenting about how Dr. Chris is incredible at delivering pain-free freezing, and how he has an amazing chair-side manner.  Dr. Chris loves sharing information with his patients and everyone who has teeth about how to care for their teeth, avoid tooth decay, and the treatments available to help them overcome their tooth pain or other dental issues so they can enjoy life and food to its fullest!

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