Young children often suck on their thumbs. It's perfectly normal, even though some parents fret about it.
"This is usually very reassuring news to parents: Thumb- and finger-sucking habits are common and typically harmless behaviors of infancy and childhood," says Douglas S. Ramsay, M.D., professor of orthodontics and pediatric dentistry at the University of Washington School of Dentistry.
Roughly one out of every three children ages 1 to 4 will suck his or her thumb at least sometimes. About one in five children will still be doing so at age 5 or older. The habit is typically harmless if the child does it occasionally, such as during "tuck in" at bedtime, or in association with a stressful event.
When it's a problem
Older children who chronically suck their thumbs or fingers may need guidance from parents or a dentist to stop the habit, Dr. Ramsay says. That's because the chronic sucking habit can cause the child's permanent teeth to become crooked.
"The kids you worry about are the ones who suck their fingers while watching TV and while they're in the car and while they sleep—and oftentimes, during school. These children can develop dental problems," he says.
If you're in doubt, discuss the matter with your dentist. You may be reassured to learn that if your child is tapering off the thumb-sucking, there is probably no need for treatment. That's particularly true if the child still has baby teeth.
"If the habit stops before the permanent teeth erupt, dental problems are usually self-correcting," Dr. Ramsay says.
Often children themselves will want help to stop. It has to do with social acceptance. A child who is sucking his or her thumb is more likely to be teased by other children, says the American Academy of Pediatrics.
"Your pediatric dentist will carefully watch the way your child’s teeth erupt and jaws develop, keeping the sucking habit in mind at all times. Because persistent habits may cause long-term problems, intervention may be recommended for children beyond 3 years of age," says Dr. Ramsay.
How to break the habit
If you think your child has a problem, you might want to deal with the habit initially by ignoring the behavior. In other words, don't give the child attention when he or she thumb-sucks. Some children unconsciously suck their thumb in order to get attention, even if it's disapproving attention, Dr. Ramsay says.
Put an obstacle on your child's hand. You might try a sock or a glove. You also can buy specially designed mittens or a plastic thumb guard, either of which makes sucking difficult.
Another idea: Provide rewards for positive behavior. Praise your child whenever you notice that he or she is not sucking the thumb. You might mark a star on a calendar when the child goes without thumb-sucking for a day or leaves the sock or glove on all night. Stars could earn an extra story, a trip to the library or some other reward.
Your orthodontist also can give you advice about how you can gradually phase out the use of these methods to keep the habit from returning.
In some cases, your orthodontist may need to place a device inside the child's mouth that holds the thumb slightly away from the roof of the mouth. This interferes with the suction produced when the thumb is inserted into the mouth. The device hangs down from behind the upper front teeth. It allows the child to eat, but interferes with the sensory stimulus of thumb-sucking. The appliance may need to stay inside the mouth for six to 10 months to be effective.
Intervention may need to occur between ages 3 and 6. Permanent teeth usually begin to erupt at approximately age 6.