Dental Care for Children – Thumb Sucking 101

Psycology behind it

Kids do it. So do chimpanzees and other primates.

Many times it starts in the womb.

It comforts, soothes and calms the child and provides an overall pleasurable sensation.

When the habit is developed, a favorite finger may be sucked on…not necessarily the thumb.

At birth, thumb sucking may be looked at as an innate instinct i.e. at birth a baby suckles for nourishment. This may develop into a habit as the child ages. As a child gets older, other reasons for thumb sucking may include being scared, bored, sick, tired, adjusting to a new situation such as daycare and/or falling asleep.

As mentioned previously, at birth, thumb sucking can be seen as an innate process. This is called nutritional suckling. In addition to providing nutrition, the thumb sucking brings warmth and comfort.

At a certain age, the child stops thumb sucking and gets warmth and pleasure elsewhere. This is the desired ‘normal’ reaction. When the child continues to thumb suck, it is because they are experiencing pleasure. This is known as emotional sucking.

Most children stop their thumb sucking habit between the ages of two and four years old. This is about the time that they go to school. The embarrassment of being seen by other children acts as a deterrent.

In some cases, thumb sucking may continue into adulthood. This may be due to:
1) Continuation of the habit.
2) Stereotypic movement disorder (SMD): SMD is a motor disorder with an onset in childhood. It is repeated motor behaviour such as head banging or hand waiving. SMD interferes with normal activities and may cause bodily injury.

Thumb sucking, though not as physically obvious as the above actions, is included in the category of SMD.

Intensity of thumb sucking

In general, most cases of thumb sucking may not be looked at as a problem in young children until their adult teeth come in. This is usually at about six years old. Before this time, there tends to be no effect on their teeth or jaws. However, at times, the intensity of thumb sucking may be a factor even in children with primary (baby) teeth. The greater the intensity of thumb sucking, the greater potential for damage and undesirable movement of the teeth. This applies to both the primary and adult teeth.

If a child rests their thumb gently in their mouth as opposed to intensely, then less damage may occur.

If the child is an aggressive ‘sucker’ then it may be wise to end their habit before their adult teeth come in…say at about four years of age. Otherwise, when the adult teeth come in, the thumb sucking may cause problems with proper growth of the mouth and alignment of the teeth. More specifically it can cause changes in the palate (roof) of the mouth.

As long as the thumb sucking habit is broken by about five years of age, when the permanent teeth come in, the damage seems to be reversible.


Generally speaking, thumb sucking does not have deleterious effects in children who just have primary teeth; however, the intensity of the thumb sucking should be taken into account.

In the next blog, we will look at different strategies to stop thumb sucking…until then.

Yours in dental health,

Dr. F. Keshavarz Dentistry, Brampton Dentist

For any dental questions or concerns, please give us a call today @ 905.791.3867…you’ll be glad you did!


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