December 15, 2009

By Claire McCarthy, M.D.
Boston Children's Hospital
There's something so sweet, at first, about seeing your baby curled up with her thumb in her mouth. But as she gets older and the thumb is still there, and visions of buck teeth start swirling in your head, it's a lot less cute.
Sucking, whether it's on the breast, bottle, a pacifier or a thumb, is very soothing to babies. It's so strongly associated with feeding and nurturing that it's no wonder some kids don't want to give it up. That may be why 25% to 50% of 2-year-olds suck their thumbs.
It can be a difficult habit to break. Unlike pacifiers, which can be taken away, thumbs are, well, attached. And many children suck their thumbs without realizing it, or while they sleep. So when do parents need to step in and do something?
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When To Step In
According to the American Dental Association, you don't need to stop kids from sucking their thumbs until their permanent teeth come in around age 6. But some research suggests that thumb-sucking and pacifier use after age 2 can cause dental problems. So waiting until age 6 may be too late. It's probably a good idea to stop before then for psychological reasons, as young children who suck their thumbs may be teased at school by their peers.
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How To End Thumb-Sucking
Here are some ideas about how to end thumb-sucking in your house:
- Talk about stopping first, to get your child used to the idea. If your child is 4 or older, talk about why it's bad for his teeth. Ask your child for good ways to help him stop. Younger children may have more trouble grasping the idea that thumb-sucking has dental consequences, so you may have to take the "Big girls and boys don't suck their thumbs" approach, and give them a heads-up that you're going to help them stop.
- Be positive. Don't blame your child. Understand that giving up thumb-sucking is hard for many children; you don't want to make them feel bad.
- Understand your child's thumb-sucking. Does he do it when he's tired, worried or sad? Once you have a better idea of what makes that thumb head toward the mouth, you can begin to think about other ways your child can comfort herself and perhaps look at ways to limit the stress and worry in her life. (This is a good thing to do anyway!)
- Think about your timing. Don't take this on if something big is going on in your child's life, like a move, a new sibling, or starting a new daycare. And don't take it on if you're asking something else of him, such as potty training. Be fair!
- Use incentives with realistic goals. "If you can keep your thumb out of your mouth this morning, we'll go to the park this afternoon." All morning may be too long. You may need to work up to that. My personal bias is that incentives are best when they involve time with you, an activity, or something healthy or educational (like a trip to the library) rather than toys or candy. At the very least, use toys or candy sparingly.
- Try reminders, like a Band-Aid on the thumb. If your child sucks while she sleeps, try putting a sock on her hand. Stop if either upsets her.
- Notice achievements, no matter how small. If, for example, your daughter usually sucks her thumb in the car, and you look in the rear view mirror and see that she's not, say something!
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When the Usual Strategies Fail
If your child is older than 6 and having either social or dental problems due to thumb-sucking, you may need to take more dramatic steps. These should be considered only if you've tried everything else, and after talking with both your dentist and your pediatrician.
- Adversive therapies You can buy icky-tasting stuff to paint on the finger that makes it less appealing to suck on it. I've known parents who've used spicy things like salsa, too. It's interesting, though, how many kids either find a way to get the stuff off or get used to the taste.
- Mechanical devices Your dentist can fit your child for a device that goes in the mouth to make thumb-sucking impossible. This can be especially useful for those night suckers but, again, should only be done in dire circumstances.
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The Bottom Line
It's important to be patient. While most kids give up thumb-sucking, it's not always a quick process. Just when you think your child just might suck his thumb as he gets his high school diploma, remember that this, too, shall pass.
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Claire McCarthy, M.D., is an assistant professor in pediatrics at Harvard Medical School, an attending physician at Children's Hospital of Boston, and medical director of the Martha Eliot Health Center, a neighborhood health service of Children's Hospital. She is a senior medical editor for Harvard Health Publications.