Not all thumb sucking results in damage to the teeth or mouth. For example, passively holding the thumb in the mouth doesn’t typically cause damage. However, active thumb sucking with a lot of motion can cause damage to primary (baby) teeth, though this usually corrects itself as the permanent teeth come in. Persistent, vigorous thumb sucking can sometimes cause misalignment of your child’s permanent teeth and affect the jaw or the shape and roof of the mouth. Thumb sucking may also expose your child to dirt, bacteria, and viruses.

A study, reported in Pediatrics, found that children who suck their thumbs were less likely to experience allergic reactions to substances such as pollen and dust mites later on in life. So, deciding when, or even if, you may want to discourage thumb sucking involves various factors.

Vigorous thumb sucking can have many effects on the teeth and mouth. That’s because of the repetitive pressure the thumb and sucking places on the teeth, jawbone, and roof of the mouth. It may cause any of the following:

  • overbite, where the front teeth protrude out from the jaw and mouth
  • other bite issues, such as the bottom teeth tipping inward toward the back of the mouth or an open bite, where the top and bottom teeth don’t meet when the mouth is closed
  • changes to the shape of the jaw, which can also affect the alignment of the teeth and speech patterns, such as the development of a lisp
  • sensitivity of the roof of the mouth

Most of these issues resolve or won’t develop at all if thumb sucking drops off by the time the permanent teeth are in. Children who suck their thumb for a long time and continue sucking their thumb vigorously may be at increased risk for these side effects.

All children should start regular dental visits by 1 year of age. If later on you notice your child’s front teeth are jutting out, or if your child seems to have a problem with their bite, talk to a pediatric dentist about your concerns.

Your child’s permanent teeth will not start coming in until they are 6 years old. However, damage can be done to their mouths before that time that may or may not correct itself. For that reason, it’s a good idea to talk to a doctor sooner rather than later, especially if you are concerned.

If your child is past the age of 4 and still frequently sucks their thumb during the day, or if you’re concerned about your child’s thumb sucking, talk to their pediatrician or dentist. They may recommend treatments or strategies you can try to help your child stop sucking their thumb. They may also recommend letting your child continue with the behavior until they give it up on their own, despite the possible effects on their baby teeth.

Many children stop sucking their thumbs on their own sometime between ages 2 and 4. Consistent or vigorous thumb sucking that lasts past that time may affect the alignment of your child’s permanent front teeth and the shape of their mouth.

If you are considering trying to get your child to stop sucking their thumb, realize that whatever method you choose has the best chance of success if your child also wants to stop. Helping your child to stop thumb sucking may depend upon their age.

In older children, talking to your child may be enough, especially if they’ve been teased about the practice by other children. Peer pressure can be a powerful deterrent in kids who are entering preschool or kindergarten. If at any point your child is resistant to giving up their thumb sucking, it’s best to just ignore the behavior. Sometimes, the more attention you pay to it, the more persistent it becomes.

Here are other ways to help your child stop sucking their thumb:

Notice your child’s thumb sucking triggers

Some children thumb suck when they are bored, tired, anxious, or hungry. If they appear to suck their thumb as a self-soothing strategy during stressful situations, attempt to figure out the root cause of their anxiety so you can address it. If they are thumb sucking at other times, try to engage them in an activity that uses their hands, such as drawing or playing catch. But don’t let thumb sucking become a means of getting attention, either positive or negative.

Use positive reinforcement

Engage your child in wanting to stop the behavior by praising them when they don’t thumb suck or by letting them track the absence of the behavior with a sticker chart.

Keep them on track with gentle reminders

If your child absentmindedly thumb sucks, calmly tell them to stop. Be prepared to do this many times. This only works if your child wants help stopping their thumb sucking.

Ask your child’s dentist for help

Your child’s dentist can talk to them about their thumb sucking, letting them know of the type of damage they may be doing.

Try an orthodontic device

There are removable and nonremovable orthodontic devices that can be used to disrupt the ability of a child to thumb suck. A pediatric orthodontist can work with you to determine which type is best for your child.

Use thumb shields

There are various types of soft plastic or fabric thumb guards that are available without a prescription if your child is interested in a reminder not to suck their thumb. Your child can wear them all the time or during the times they are most likely to thumb suck. You can also cover your child’s thumb at night with a glove, mitten, or sock if they thumb suck in their sleep. If your child only sucks their thumb while sleeping, remember that this is not something they can control.

Why do kids suck their thumbs? | Benefits

Thumb sucking is a soothing, reflexive behavior. It begins in the womb, before birth. Infants and babies often continue this relaxing practice after birth, which often helps to soothe them into sleep. In some children, thumb sucking may continue into the toddler years and is often utilized as a self-soothing mechanism for coping with stressful situations.

According to the American Dental Association, most children stop thumb sucking somewhere between 2 and 4 years of age.

Thumb sucking vs. pacifiers

One thing you shouldn’t do is replace your child’s thumb sucking habit with a pacifier habit. Pacifier sucking creates the same potential for tooth damage that thumb sucking can. Pacifiers can also fall on the ground, making them germ magnets. The only upside to pacifier use is that you can take them away from your child as a strategy for breaking their habit.

Thumb sucking is a natural reflex that begins before birth. Many children continue the practice up until age 2 or longer. Thumb sucking typically resolves on its own, but it can occasionally cause damage to the mouth, especially if it lasts past age 4, and if the child sucks vigorously and often. This practice may also expose children to germs and viruses.

Parents can help their child break the habit. Your child’s pediatric dentist or pediatrician can also help.