How to Stop Thumb Sucking in Kids

Thumb sucking is a common habit in kids.
 sandrajolly / Royalty-free / Getty Images

Your baby likely started sucking his thumb in the womb—and then perfected the habit as an infant. When a child is young, it’s normal to pop a finger or thumb in his mouth as a way to calm down, self-soothe or fall asleep.

At that age, there’s no harm in this habit. However, if you notice your young child doing this, consider substituting a pacifier. Although pacifiers can cause the same problems, it’s an easier habit to break.

Once a child reaches toddlerhood, thumb sucking usually goes away on its own. Although some older kids may replace it with other habits, like nail biting.

If thumb-sucking is used as a coping skill, a child starts to develop other methods around ages 2 to 4, such as developing language skills. This naturally ends the practice of sucking the thumb, and everyone can move on.

If the behavior continues into the preschool years, issues can arise with both thumb-sucking and pacifier-sucking. If a child doesn’t stop the practice naturally, though, it can lead to developmental issues, both in the mouth and with speech.

Although peer pressure at school typically curbs the habit once a child reaches age 5 or 6, a parent might want to take measures to stop thumb-sucking long before that time.

Potential Dental Problems From Thumb Sucking

Thumb and finger sucking can impact a child’s mouth and jaw as early as 2 years old. The sucking puts pressure on the soft tissue of the roof of the child’s mouth, as well as on the sides of the upper jaw.

When this occurs, the upper jaw can narrow, which prevents the teeth from meeting properly when the jaw is closed. This is an issue that has an expensive fix—braces—but the impact goes beyond that. Narrowing of the jaw can also lead to speech problems, such as a lisp.

As the child grows up, a gap between upper and lower teeth can develop from thumb sucking. At this point, the structure of the jaw has changed and the tongue muscles likely haven’t developed properly.

If she sucks her thumb until after she’s lost her baby teeth and the permanent teeth come in, a “buck teeth” appearance can also develop.

The severity of the physical problems stemming from the habit depends on how vigorously a child sucks his thumb. If he simply rests his thumb in his mouth without actually sucking too much, there will likely be fewer problems than if it’s an active movement. Keep a close eye on how your child sucks his thumb, and make a move to curb the habit earlier if you notice vigorous sucking.

A 2016 study published in Pediatric Dental Journal found that a callus on the thumb or finger caused by sucking predicts a malocclusion—imperfect positioning of the teeth when the jaws are closed—in children. Dentists who discovered toddlers and preschoolers sucked their thumbs often enough and vigorously enough to have formed a callus were likely to have jaw and dental issues.

The same study, however, found that when children stop thumb sucking by the age of four, any jaw or dental problems may resolve themselves. So it’s important to tell your child’s physician and dentist if your child sucks her thumb. Early identification of problems can be key to resolving them.

How to Address Thumb Sucking

Although it’s ultimately up to the child to break the thumb-sucking habit, there are several things you can do to discourage your child from sucking her thumb:

  • Stay calm. Yelling or insisting your child stop sucking his thumb right now won’t be helpful. Although you might be worried about the potential damage he’s doing to his teeth or all the germs he’s putting in his mouth, getting upset isn’t likely to lead to cooperation.
  • Create a diversion. When you see your child sucking her thumb, give her something to do with her hands. If she often sucks her thumb when she’s nervous, give her a stress ball to squeeze. If she sucks her thumb when she’s bored, encourage her to color a picture, toss a ball back and forth, or finger paint—anything that keeps her hands busy and out of her mouth will work.
  • Offer plenty of praise. Whenever you see your child remove the thumb from his mouth on his own accord, heap the praise on him. Say something like, “Great job remembering to take your thumb out of your mouth,” or “I noticed you are keeping your hands on your toys and out of your mouth today. Great job!”
  • Teach new coping skills. Your child is likely sucking his thumb to cope with feeling scared, anxious, sad, or bored. Teach other strategies he can use to handle his uncomfortable feelings. Putting lotion on his hands that smells good, listening to music, or doing some simple kid-friendly yoga moves may help him feel better without sucking his thumb.
  • Point out when it’s happening. While you don’t want to give thumb sucking too much attention (your child might do it more just to see your reaction), you may want to point it out if your child isn’t even aware when he’s doing it. Saying, “No thumb,” might be a good reminder to help him become more aware of his habits. You can also say something like, “Your mouth is for eating and talking and your hands are for building and playing.”
  • Initially, you should also explain why thumb sucking is a bad idea. While a 2-year-old won’t understand a lengthy lecture about the dental damage he may be causing himself, you can tell an older child, “Sucking your thumb is bad for your teeth,” or you might go the germ route and say, “Your thumb has germs on it that you don’t want in your mouth.”
  • Use a thumb cover. If you’re really feeling desperate, purchase a plastic cover for the thumb or finger. They can range from about $20 to $40, and while that isn’t inexpensive, it’s cheaper than braces down the road. Most kids aren’t able to get them off, so it breaks the habit in about two weeks. But, there are certainly some downsides. Kids struggle to play or feed themselves because the cover limits hand use.
  • Offer rewards. Positive reinforcement could motivate your child to keep her fingers out of her mouth. Create a sticker chart and offer her stickers at certain times throughout the day. While you can’t stare at her for 24 hours, you can say, “Here’s a sticker because you didn’t suck your thumb once while we played that game.” You might even tell her, “When you get five stickers we’ll go play at the park,” if she needs more than a sticker to stay on track.
  • Apply a bad taste. There are many stories about parents putting cayenne pepper or hot sauce on their children’s fingers in a desperate attempt to get them to stop thumb sucking. But taking extreme measures isn’t a good idea and it can be quite upsetting to kids. You might try a little vinegar on a child’s thumb to make it taste different without it being dangerous or harmful. You also don’t want to take away your child’s coping skill until she’s ready to give it up.

Be Patient

If your child is still a toddler, the best thing you can do is be patient. Although it’s frustrating—and sometimes disgusting to watch your child put his dirty thumb in his mouth—he’ll likely stop on his own when he’s ready.

It can be stressful for a parent to try to break a thumb-sucking habit in a child who’s just not responding. If your child is five or older, talk to the pediatrician or pediatric dentist about the next steps you can take. Hearing a warning from a dentist may also help motivate your child to stop thumb sucking.

Keep in mind that the same strategies don't work for all kids. Some respond to reward systems while others become motivated after learning about how it could affect their teeth. So keep working on it but be patient with the process.

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