Thumb sucking – Is it okay?

Thumb-sucking-advice-victoria-dentalMany children use thumb sucking as a means to soothe themselves. At birth, babies reflexively suck any object placed in their mouths, and this the reflex responsible for ensuring breast feeding. For many babies, thumb sucking becomes a habit that may last several years or more. A question often asked by parents is whether or not thumb sucking (or use of a pacifier/soother) will have any negative impact on the mouth or teeth.

Thumb sucking can have long term consequences.

Thumb sucking results in forces being active in the mouth that would not be present if thumb sucking did not occur. Specifically, due to the position of the thumb and the act of constantly sucking, the upper front teeth are pushed toward the lip, while the lower front teeth are pushed toward the tongue, and the upper arch of the mouth feels pressure in an upwards direction. These forces may vary depending on the intensity and the frequency or duration of the sucking, and whether the thumb, finger or other object is used. In small children prior to the adult teeth coming in, thumb sucking may alter the shape of the upper arch of the mouth, making it taller and narrower. If thumb sucking persists while the adult teeth are coming in, the adult teeth may come in with a forward slant. The adult teeth may not move down as fully or straight as they would be if the thumb was absent from the mouth. The result of the thumb sucking beyond the age of about 6, when the adult teeth come in, can be an ‘open bite’ in which the front teeth do not meet when the molars bite down, and an ‘overjet’, where the top front 4 to 6 teeth protrude forward, and the lower front teeth may slant in towards the tongue.

Can change the shape of the palate.

Some children who do thumb suck do not display any significant defects in dental positioning. However, it has been shown that abnormal sucking habits are more frequently associated with imperfect positioning of the teeth. For example, in a study that looked at children with various thumb sucking habits between the ages of 3 and 5 years, those children that sucked their thumbs tended to have upper mouth arches that were deeper and narrower, presumably as a result of the upward force of the thumb on the top of the mouth (1). Another study showed that a group of 7 to 13 year olds who were persistent thumb suckers were more likely to have and ‘open bite’ and ‘overjet’ than non-thumb suckers (2). Narrow upper mouth arches can be associated with crowding when the adult teeth come in, while an open bite and/or overjet is likely to require orthodontics to straighten and align the teeth.

Change the bottle for the cup.

Because of the impacts that thumb sucking can have on the upper arch and the teeth position, parents are encouraged to try to eliminate thumb sucking behaviour in their children around the age of about 2 or 3 years, and the same for use of pacifiers. Similarly, baby bottles should no longer be used as soon as the child is able to use a sippy cup instead. The reason for this is that the child may bite the bottle, and the weight of holding the bottle by the teeth can have a negative impact. Thumb sucking becomes a major concern if it continues beyond about age 6, when the permanent teeth begin to erupt. If thumb sucking continues, orthodontics may be required to restore the position of the teeth. Generally, the sooner the thumb sucking habit is stopped, the better the outcome for the position of the teeth.

Tips and tricks to stop the habit.

Luckily, most children naturally stop sucking on their thumbs or using pacifiers between about 2 and 4 years of age. This being said, it can be difficult to stop habitual behaviours like thumb sucking. Even once the child has a desire to quit the habitual behaviour, it could take a month or two for the behaviour to stop altogether. Here are a few ideas that could be of help to change your child’s habits.

  • Praise the child for not sucking the thumb to give positive reinforcement, rather than negative comments, which may increase anxiety and sucking.
  • If the child is sucking due to insecurity, try to focus on the root cause of the anxiety and provide comfort.
  • If the child is sucking due to boredom, try to get their attention with an activity.
  • Bandage the thumb or put a sock or glove on the hand, particularly at night.
  • As a last resort, consider a dental appliance that fits in the roof of the mouth and makes it difficult to suck a thumb.


  1. Yemitan, daCosta, Sanu, Isiekwe (2010). Effects of digit sucking on dental arch dimensions in the primary dentition. Afr J Med Med Sci. 39(1): 55-61.
  2. Mistry, Moles, O’Neill, Noar (2010). The occlusal effects of digit sucking habits amongst school children in Northamptonshire (UK). J Orthod. 37(2): 87-92.