Thumbsucking and Pacifier Use

Thumbsucking is a natural reflex for children. Sucking on thumbs, fingers, pacifiers or other objects may make babies feel secure and happy and help them learn about their world.

Young children may also suck to soothe themselves and help them fall asleep.

How Can Thumbsucking Affect My Child’s Teeth?

After permanent teeth come in, sucking may cause problems with the proper growth of the mouth and alignment of the teeth. It can also cause changes in the roof of the mouth.

Pacifiers can affect the teeth essentially the same ways as sucking fingers and thumbs, but it is often an easier habit to break.

The intensity of the sucking is a factor that determines whether or not dental problems may result. If children rest their thumbs passively in their mouths, they are less likely to have difficulty than those who vigorously suck their thumbs.
Some aggressive thumbsuckers may develop problems with their baby (primary) teeth.

https://www.mouthhealthy.org/en/az-topics/t/thumbsucking