Here is a picture of my one-year-old daughter, Ada Grace.

Yes, she’s cute. I agree. More to the point, do you notice that she has her thumb in her mouth?  It’s there ALL THE TIME. So, naturally, people ask me how long I’m going to let her suck her thumb.  As a parent, I want to answer, “As long as it makes her stop crying.” As an orthodontist, though, I know that thumb sucking can cause some bad things to happen in the mouth.child who is thumb sucking

In this post, I’m going to cover six potential consequences of thumb sucking for tooth/jaw development. In the next two blog posts, I’ll talk about 1) the timeframe for when these consequences start to happen (i.e., how long I can “let” Ada suck her thumb to her heart’s content) and 2) strategies to eventually get her to drop her thumb sucking habit. For the purposes of this discussion, “thumb sucking” includes other finger sucking or habits like cheek/lip sucking or sucking on a piece of clothing.


Here are some of the negative consequences of thumb sucking:

  1. Constriction of the cheeks during sucking can constrict the growth of the jaws, preventing them from growing to their full side to side width.  This may lead to improper tooth relationships (posterior crossbite), improper jaw joint relationships, and aberrant growth patterns of the jaws. So, bottom line, it can affect growth.
  2. When the thumb sits in the roof of the mouth, it occupies the space that should be occupied by the tongue.  The current theory is that the tongue should, at rest, sit just off of the front portion of the roof of your mouth; and it is the tongue that shapes the roof of the mouth.  Again, this can affect the growth and development of the palate.
  3. When the tongue can’t sit where it should, it has to sit lower in the mouth (more behind the bottom teeth).  This can lead to improper tongue posture which may have wide-reaching effects to include breathing and sleep quality.
  4. Likewise, when the tongue sits lower, it may occupy space between the upper and lower front teeth causing a “tongue thrust.”  This “tongue thrust” may prevent the upper and lower front teeth from coming fully together (we call this an anterior open bite). When you have an anterior open bite, and you bite into a slice of pepperoni pizza, guess what doesn’t come into your mouth?  The cheese and the pepperoni! What a terrible way to eat! Actually, this can result in strange eating patterns like trying to bite with the side of your mouth (where teeth actually touch).
  5. Thumb sucking can inhibit the eruption of permanent teeth, again resulting in open bite. The inhibition of eruption of teeth and the tongue thrust are synergistic, meaning they can make the other one worse.
  6. And, finally, thumb sucking can cause front teeth to stick out, making them at greater risk for trauma.