Thumb sucking is one of the most common habits of children. The habit starts early in life, with 90% of newborns showing some form of hand sucking by 2 hours of age.
Thumb sucking is normal in infants and young children and should cause no permanent problems if it is not continued past the age of 5. Likewise, it is generally harmless for infants to use pacifiers.
The American Academy of Pediatric Dentistry states that most children stop thumb sucking on their own between the ages of 2 and 4. The Academy states there is no reason to be concerned until the front teeth start erupting. At this point, some problems may occur, including bite problems, or protruding front teeth. The intensity of the thumb sucking is a factor in determining if problems might develop. If your child is an aggressive thumb sucker and damage is being done to the primary (baby) teeth, see your dentist. Other problems that may occur with thumb sucking are sore thumbs, infections, and calluses on the thumb.
It is thought that pacifier use may actually be better than thumb sucking for the following reasons:
Pacifiers are softer and cause less damage to the teeth.
The plastic rim on the pacifier provides some relief of the tension placed on the teeth.
Pacifiers can be cleaned.
Talk to your child's healthcare provider or dentist if you are concerned with your child's thumb sucking.