Thumbsucking is one of the most common habits of children. The habit starts early in life. It should cause no permanent problems if it stops by age 5. It's also generally harmless for babies to use pacifiers.
Most children stop thumbsucking on their own between the ages of 2 and 4. There is no reason to be concerned until the front teeth start erupting or breaking through the surface. At this point, some problems may occur, including bite problems, or protruding front teeth. The intensity of the thumbsucking is a factor in determining if problems might develop. If your child is an aggressive thumbsucker and damage is being done to the baby (primary) teeth, see your child’s dentist. Other problems that may occur with thumbsucking are sore thumbs, infections, and calluses on the thumb.
Experts believe that pacifiers may actually be better than thumbsucking for the following reasons:
Pacifiers are softer and cause less damage to the teeth.
The plastic rim on the pacifier eases some of the tension placed on the teeth.
Pacifiers can be cleaned.
Talk with your child's healthcare provider or dentist if you are concerned with your child's thumbsucking.