Thumb sucking habits are common in infants, and as they grow older, they tend to stop them. In most cases, this habit ceases spontaneously between 2 and 4 years of age. Experts say that children below the age of 5 years should not be forced to stop thumb sucking. Sometimes, even adults might resort to thumb-sucking, during stress and anxiety.

Thumb sucking usually involves placing the thumb into the mouth and rhythmically repeating sucking contact for a prolonged duration. It can also be accomplished with any organ within reach such as other fingers and toes.

Thumb Sucking is Prevalent in Children Across the World

Thumb sucking is a behavior that can be grouped under a list of habits known as non–nutritive sucking habits. Within this group, we can also find the use of pacifiers, blankets, or sucking on other fingers as a comforting behavior. 

Sucking by itself is a primitive reflex that appears early in infants. Sucking behavior in children is associated with self-comfort and security feeling for a release of psychological and physical tension. 

Thumb sucking is prevalent among children all over the world, including all socioeconomic classes. Prevalence of non-nutritive sucking ranges from 82% during the first five months of life, to 48-73% between 2 and 5 years. It persists in 12.1% of children older than 7 years, and 1.9% of 12-year-old children.

Consequences of Thumb Sucking

Thumb sucking can be characterized by the frequency, intensity, and duration of the habit. The duration of the force in the thumb is more critical than its magnitude, and the resting pressure has the greatest impact on the position of the tooth.

1. Thumb sucking can cause dental malocclusions, (the abnormal alignment of the upper and lower teeth). Frequent thumb sucking can lead the upper jaw (also known as maxilla, which holds the upper teeth) and the teeth in the upper jaw to protrude from the face.

  • The pressure of the thumb forces the lower incisor teeth to tip towards the tongue.

  • Anterior Open Bite: Open bite is a dental condition where the top and the bottom teeth do not make proper contact. Open bites may make speaking and chewing difficult for your child.

  • Crossbite: The formation of the upper jaw is too narrow for the lower jaw, so the upper and lower teeth do not fit together properly. This can occur as a result of the flexing of the cheek muscles while your child is sucking his/her thumb.

2. Thumb sucking can also lead to deformity of the nail or infection in the nail bed (paronychia). Prolonged exposure of the skin to saliva (the colourless, complex fluid produced by the salivary glands in the mouth) can lead to maceration and irritation. 

Maceration occurs when the skin is in contact with moisture (due to saliva) for too long, causing pain and discomfort and making the skin vulnerable to infections. 

3. Thumb sucking exposes your child to various foreign substances such as bacteria, viruses, and other pathogens that can cause infections and illnesses like the common cold, the flu, stomach upset, a blocked nose, coughing, or sneezing.   

4. Thumb may have blisters (sucking pads or calluses). Repeated thumb sucking results in friction, burning, and infection, resulting in blisters. 

When Should You Intervene?

Thumb-sucking in children younger than 4 is usually not a problem. Children who suck their thumb around age 4 or 5, and continue sucking their thumbs at age 6, have to be discouraged. 

Remember, whatever method you choose to get your child to stop thumb sucking, will only work if your child also wants to stop doing it. 

If your child is entering preschool (3-5 years) or kindergarten (5-7 years), talking to your child may be enough, especially if they’ve been teased about this practice by other children. If at any point your child is resistant to giving up his/her thumb sucking, it’s best to just ignore the behavior. The more attention you pay to it, the more persistent it becomes.

Treatment for Thumb Sucking

Thumb sucking in children less than 3 years of age do not need any treatment. At these years, the child begins to assert his/her independence from the mother and inevitable tensions and frustrations may occur, causing an occasional short-lived sucking episode. If your child is in preschool and sucks his/her thumb only before going to bed, it can be disregarded.

Treatment for older children initially involves counseling the patient and the parent, implementation of behavior-modification techniques such as Positive Reinforcement (using praises or rewards to shape your child’s behavior). Applying a nasty tasting substance to the child's thumbs or nail (bitter nail polish), or applying thumb guard can also be done, only after consulting your peadiatrician.

Resistant cases have to be treated by a peadiatric dentist with the use of dental mouth appliances such as mouth guards, retainers, or braces. Children with dental malocclusion and anterior open bite will require some form of active orthodontic treatment. Consult your peadiatrician to understand how to reduce/stop thumb sucking in your child.

Disclaimer: This article is written by the Practitioner for informational and educational purposes only. The content presented on this page should not be considered as a substitute for medical expertise. Please "DO NOT SELF-MEDICATE" and seek professional help regarding any health conditions or concerns. Practo will not be responsible for any act or omission arising from the interpretation of the content present on this page.