Most children suck their fingers or thumbs from a very young age, and most of them grow out of it by age three without causing permanent damage to their mouth or teeth.
If your child continues thumb sucking as permanent teeth start to come in, we recommend proactively helping your child break this habit. The reason: sucking of fingers or thumbs beyond age 3 can begin to affect the teeth, mouth and even face shape, and it can require orthodontic correction at a later age.