Short answer: Thumb sucking and pacifier use are a natural self-soothing behavior in infancy. It is generally recommended that the habit be stopped at around age 3-4. Intense sucking that continues until the permanent front teeth erupt can lead to an open bite in the front teeth, the upper teeth being pushed forward and narrowing of the upper jaw. If the habit stops early, some of these effects can lessen on their own.
A baby sucking their fingers or calming down with a pacifier is a familiar sight to most parents. Thumb sucking and pacifier use are behaviors medically called "non-nutritive sucking," and they are considered completely natural in the first years of life. However, when these habits continue intensely beyond a certain age, they can affect the alignment of the teeth and the development of the jaw. In this article we look at why the habit appears, up to what age it is considered normal, its possible effects and ways to stop it.
Why do children suck their thumbs?
Thumb sucking is an extension of the baby's innate sucking reflex and is most often a way of self-soothing. This reflex can be seen even in the womb; some babies are seen sucking their thumbs in ultrasound images. After birth, sucking is associated not only with feeding but also with a sense of security, falling asleep and calming down.
As the child grows, thumb sucking can become a habit that appears mostly in moments of tiredness, distress, boredom or anxiety. Children who put their thumb in their mouth while watching TV, falling asleep or entering a new environment are common. Changes such as the birth of a sibling, starting daycare or moving house can also intensify the habit. For this reason, it is important to keep the child's emotional needs in mind when addressing the habit.
Until what age is thumb sucking normal?
Thumb and pacifier sucking are normal in infancy and early childhood; most children give up the habit on their own between ages 2 and 4. Organizations such as the American Academy of Pediatric Dentistry recommend that non-nutritive sucking ideally be reduced at around age 3 and ended before the permanent front teeth erupt. The permanent front teeth usually begin to erupt at around age 6-7.
Age is not the only factor that determines the effect. The frequency of the habit (how many hours a day it lasts), its intensity (how strongly the child sucks) and the position of the thumb in the mouth also matter. Brief, gentle sucking while falling asleep and strong sucking that lasts all day do not have the same effect. For this reason, the presence of the habit in a 3-year-old should not be a cause for concern on its own; but as the child gets older and changes start to appear in the teeth, a more active approach is needed.
What are the effects of thumb sucking on the teeth and jaw?
Prolonged, intense thumb sucking or pacifier use puts constant pressure on the teeth and jaw and can change the shape of developing structures. The most common effects are:
- Open bite: Because the thumb or pacifier sits between the front teeth, the upper and lower front teeth do not touch when the mouth is closed. This is one of the most common causes of open bite in children.
- Upper front teeth pushed forward: The pressure of the thumb on the upper teeth can cause these teeth to tilt forward and gaps to form between them. Protruding teeth are more vulnerable to injuries such as falls.
- Lower front teeth tilted backward: The thumb resting on the lower teeth can push them toward the tongue.
- Narrowing of the upper jaw and crossbite: The contraction of the cheek muscles during sucking and the low position of the tongue can restrict the sideways growth of the upper jaw. As a result, a crossbite may develop in the back teeth.
- Tongue and speech habits: The gap between the front teeth can cause the tongue to push into this space during swallowing and speaking, which can affect the pronunciation of some sounds.
Although the effects of pacifiers are generally similar to those of thumb sucking, there are some differences. Because the pacifier can be controlled by the parent, it is often easier to give up. The thumb, on the other hand, is always within reach, so the habit can last longer. If a pacifier is used, choosing one in a size suited to the child's age and not dipping it in honey or sugary substances is also important in terms of cavity risk. Let us also remind you that the habit of falling asleep with a bottle can set the stage for early childhood cavities.
What are the methods for stopping the habit?
The most effective approach to stopping thumb sucking is methods that support the child and involve them in the process rather than punishing them. Pressure, scolding or teasing can increase the child's anxiety and reinforce the habit even more.
Here are some methods families can use:
- Notice the triggers: Observe in which situations your child sucks their thumb. Finding solutions for causes such as tiredness, boredom or anxiety reduces the habit.
- Use positive reinforcement: Mark the days without thumb sucking on a calendar with stickers and set small goals. Supporting success with praise increases the child's motivation.
- Keep their hands busy: At times when the habit intensifies, such as watching TV or riding in the car, keep the child's hands busy with toys, coloring or play dough.
- Special measures at bedtime: For sucking done unknowingly during sleep, a soft glove or a bandage on the thumb can be used as a reminder. Hugging a favorite toy before sleep can be an alternative way to self-soothe.
- Phase out the pacifier gradually: First removing the pacifier from daytime use and keeping it only for sleep, then ending it completely, works for many children.
If these methods are not enough, especially when the permanent teeth start to erupt, a pediatric dentist or orthodontist may recommend an appliance placed inside the mouth that serves as a reminder of the habit. These appliances are more successful when the child is willing to give up the habit, and the decision is made only after an examination.
How do the resulting problems get corrected?
When thumb sucking stops early, the open bite and mild tooth tilting that appear especially during the baby-teeth period often lessen or resolve completely on their own. The lip and tongue muscles gradually guide the teeth into a more balanced position. For this reason, ending the habit is the first and most important step of treatment.
If the habit continued after the permanent teeth erupted, or if the gap does not close after stopping, orthodontic treatment may be needed. A narrow upper jaw can be addressed with expansion appliances during the growth period. If a tongue-thrusting habit is also present, tongue exercises and, if necessary, speech therapy support treatment. In suitable ages and cases, early treatment options with clear aligners can also be considered; you can find information on this on our Invisalign First for children page. We have explained the treatment of open bite seen at an older age in our article on open bite treatment with clear aligners.
If you are wondering when your child should have an orthodontic evaluation, our article at what age can clear aligners be used may provide guidance. As a general recommendation, having the first orthodontic checkup at around age 7 helps detect growth-related problems early.
When should you see a dentist?
If thumb sucking continues intensely after age 4, if you have noticed a gap or a noticeable forward tilt in the front teeth, or if your child wants to give up the habit but cannot, a dental evaluation is helpful. At our clinic in Park Oran Ofis in Çankaya, Ankara, your child's tooth and jaw development is examined and your family is guided through the process of stopping the habit; whether orthodontic treatment is needed is planned according to the child's growth.
Frequently asked questions
Which is more harmful to the teeth, a pacifier or thumb sucking?
Both can have similar effects when used intensely and for a long time. Because the pacifier can be controlled by the parent, it is generally easier to give up. Since the thumb is always within reach, the habit can last longer.
Does an open bite caused by thumb sucking correct itself?
If the habit stops during the baby-teeth period, the open bite often lessens on its own. When the habit continues after the permanent teeth erupt or tongue thrusting is also present, orthodontic treatment may be needed. The situation is monitored through dental examinations.
Does putting a bitter product on the thumb work?
Some families use such products as a reminder, but on their own they are often not enough. The child's voluntary participation in the process and positive reinforcement give more lasting results. It is recommended that you consult your child's doctor before using any product.
