What Should I Know About My Child’s Thumb-Sucking?

Many babies and young children regularly suck their thumbs, but when is thumb-sucking normal, and when should you be concerned? How and when should you help your child break the habit—and how can your dentist help? Donna Greco, DMD discusses what you need to know.

Why do babies and young children suck their thumbs?

Headshot of Donna Greco, DMD
Thumb-sucking is natural and normal for infants and young babies. Infants have a sucking reflex that enables them to get nutrition, so sucking is very important during infancy. It is also comforting for infants and small children. Whether they are feeding, or sucking a pacifier or thumb, the habit is soothing, and sometimes it can persist into childhood.

Do most young children stop thumb-sucking on their own?

As they learn to eat solid food and drink from a cup, most children will stop thumb-sucking on their own.

When should I worry about my child’s thumb-sucking habit?

If your child is past 18 months old and still sucking a pacifier or thumb (i.e., for non-nutritive reasons), this is usually cause for concern.

What kinds of problems can thumb-sucking cause?

It mainly creates orthodontic and developmental problems by causing structural changes in the mouth, face, and muscles. When human children pass the age of about 18 months, their swallowing pattern normally changes from one in which they use their tongues and thumbs to a mature swallowing pattern with a higher tongue position and no thumb. If children don’t stop sucking their thumbs by the age of 18 months, they will have trouble developing the mature swallowing pattern.

Thumb-sucking past the age of 18 months can also be harmful because as a child sucks his thumb and creates suction, the thumb begins to work as an orthodontic appliance, modeling the growth of the jaws to a more unfavorable pattern. The lower jaw hangs lower than it should, and the upper jaw becomes narrower and begins to grow more forward and protrude. This causes problems with the child’s bite, keeps the airway from growing, and does not allow proper muscle development.

What can I do to encourage my child to break the thumb-sucking habit?

If your child is between the ages of 1½ and 2½ and still sucking his thumb or fingers, you can simply make him aware of the habit, and remind him gently to keep his thumb and fingers out of his mouth.

How can my dentist help?

For children still sucking their thumbs past the age of 2½ (when the two-year molars [the second primary molars] typically erupt), dentists have had success with various orthodontic appliances designed to help them break the habit.

One of these appliances is the Blue Grass Roller. Pediatric dental faculty at the University of Kentucky created this appliance; hence its name. Here’s how it came about. Racehorses are typically young and hot-blooded, and tend to get bored. To keep them calm and occupied, many racehorses are fitted with a bit that has a roller bar—like a fidget spinner for the tongue. The dental professors took this idea and used it to create a pediatric orthodontic appliance that fits painlessly into a child’s mouth and includes a little bead that sits behind the upper teeth. This appliance is a non-punitive method that works beautifully; children are simply instructed to use their tongues to spin and play with the bead. The position of the bead in the mouth keeps children from being able to get their thumbs or fingers in to suck. It retrains the tongue and the closing muscles of the jaw (which have not been previously developed) and helps to create a higher, more normal tongue position.

Dentists can help by prescribing the Blue Grass Roller, the only solution that is non-punitive. Older (punitive) methods have included painting children’s fingernails with a bitter substance, or fitting them with appliances with sharp barbs. Because of the bead on the Blue Grass Roller, children can exercise their underdeveloped muscles without being reminded. Children usually wear these appliances about a year. The thumb-sucking habit will typically stop within a few days, but it can take up to a year of wear for a child to get the full benefit of retraining the muscles and brain, and to develop the mature swallowing pattern.