is thumb sucking harmful to teeth

Sucking a thumb, finger or dummy is one of the ways babies calm themselves. It starts in the womb, and most children give it up on their own between two and four years old. Up to that age, it rarely causes problems worth worrying about. The question is not whether your child sucks a thumb, but for how long, how often and how hard.

What a long-standing habit can do

• Protruding upper front teeth ("buck teeth"), which are also more likely to break in a fall.
• An open bite: a gap between the upper and lower front teeth when the back teeth are together, often the shape of the thumb.
• A narrow upper jaw and crossbite, where the upper back teeth bite inside the lower ones, because the cheeks squeeze inwards during sucking.
• Speech changes, such as a lisp, and a tongue that pushes forward when swallowing.
• Problems with the thumb itself: calluses, cracked skin and infections around the nail.

A child who rests a thumb loosely in the mouth while falling asleep is at lower risk than a child who sucks hard for hours during the day. If you hear a popping sound when the thumb comes out, the sucking is strong.

The ages that matter

• Under 4: usually leave it alone, apart from gentle distraction.
• 4 to 6: a good time to help your child stop, before the adult front teeth arrive. Changes in the milk teeth often correct themselves if the habit stops now.
• 6 and older: the habit now shapes the adult teeth and the growing jaw. Get a dental assessment.

How to help a child stop

• Talk, don't scold. Shaming, slapping the hand, or the old trick of chilli or bitter neem on the thumb often makes a child suck in secret. Children stop more easily when they want to.
• Notice the triggers. Many children suck when tired, bored, watching TV or anxious. Give their hands something else to do at those times.
• Praise and a chart. A star for each day or night without sucking, with a small, non-sweet reward at the end of the week.
• Night-time help. A sock or cotton glove over the hand, or a loose bandage on the thumb, reminds a sleeping child without punishing them.
• Ask the dentist to talk to your child. Hearing it from someone outside the family often works surprisingly well.

If none of this works in an older child, a dentist may suggest a habit-breaking appliance: a small wire device fixed behind the upper teeth that makes sucking less satisfying. It is a last step, used when the child understands and agrees, never as a punishment.

Dummies and pacifiers

Dummies cause similar changes. They are easier to take away than a thumb, so aim to stop dummy use by about two to three years. Never dip a dummy in honey, sugar or sweetened gripe water, as that coats the new teeth in sugar.

If your child is past six and still sucking, our paediatric dental and orthodontic specialists can check the bite. Read more about the bite problems involved on our abnormal bite page.