Infants may use pacifier or thumb or fingers to soothe themselves

Thumb sucking is a behavior found in humans, chimpanzees, and other primates.^[1] It usually involves placing the thumb into the mouth and rhythmically repeating sucking contact for a prolonged duration. It can also be accomplished with any piece of skin within reach (such as the big toe) and is considered to be soothing and therapeutic for the person.

At birth, a baby will reflexively suck any object placed in its mouth; this is the sucking reflex responsible for breastfeeding. This reflex disappears at about four months of age; thumb sucking is not purely an instinctive behavior and therefore can last much longer. Moreover, ultrasound scans have revealed that thumb sucking can start before birth, as early as 15 weeks from conception; whether this behavior is voluntary or due to random movements of the fetus in the womb is not conclusively known.

Children suck on objects (including pacifiers) to soothe themselves; sucking is one of a baby’s natural reflexes and completely typical for babies and young children.^[2] As a child develops the habit, it will usually develop a "favorite" finger to suck on, in much the same way it develops a favorite hand to write with. It is not known if the preference for a hand to suck on affects handedness in any way, or vice versa.

Thumb sucking can start as early as 15 weeks of growth in the uterus or within months of being born. Prior to 12 weeks, the fetus has webbed digits. Most thumb-suckers stop gradually by the time they are five years old. Nevertheless, many older children will retain the habit, some into adulthood. Thumb sucking in adults may be due to stereotypic movement disorder, another psychiatric disorder, or simply habit continuation where the adult thumb sucker can avoid the social implications by indulging stealthfully or by ignoring any outside reaction. For many who have continued to adulthood occlusal effects were either minimal or nonexistent.

[edit] Dental problems

Alveolar prognathism, caused by thumb sucking and tongue thrusting in a 7 year old girl.

Thumb-sucking can cause problems for dental development. To prevent their children from sucking their thumbs some parents put hot sauce or bitter-tasting chemicals such as thiomersal^{[citation needed]} on their child's hands — although this is not a procedure encouraged by the American Dental Association^[3]: or the Association of Pediatric Dentists. During the 1950s, parents could get a series of sharp prongs known as "hay-rakes" cemented to a child's teeth to discourage sucking.

Most children stop sucking on thumbs, pacifiers or other objects on their own between two and four years of age. No harm is done to their teeth or jaws until permanent teeth start to erupt. The only time it might cause concern is if it goes on beyond 6 to 8 years of age. At this time, it may affect the shape of the oral cavity or dentition.

Newborn baby thumb sucking

Tips from the American Dental Association [1]:

• Praise children for not sucking, instead of scolding them when they do.
• If a child is sucking its thumb when feeling insecure or needing comfort, focus instead on correcting the cause of the anxiety and provide comfort to your child.
• If a child is sucking on its thumb because of boredom, try getting the child's attention with a fun activity.
• Involve older children in the selection of a means to cease thumb sucking.
• The pediatric dentist can offer encouragement to a child and explain what could happen to its teeth if it does not stop sucking.
• Only if these tips are ineffective, remind the child of its habit by bandaging the thumb or putting a sock/glove on the hand at night.

Summary of Best Practices Recommendations:

• American Academy of Pediatrics ^[5]: Most children suck their thumbs or fingers at some time in their early life. The only time it might cause concern is if it goes on beyond 6 to 8 years of age or affects the shape of the child's mouth and the position of teeth.
• American Dental Association ^[3]: Children suck on objects as a natural reflex; however, during and after the eruption of the permanent teeth, such sucking may cause problems with the skeletal development of the mouth and alignment of the teeth.

[edit] Fictional references

• The Peanuts character Linus van Pelt is possibly the most well-known example of fictional thumbsuckers. He is frequently shown sucking his thumb and holding a security blanket throughout the comic strip, a habit at odds with his overly mature and philosophical nature.
• Irish Mythological figure Fionn mac Cumhaill commonly sucked his thumb while thinking, though in his case it was to gain access to the oil of the salmon of wisdom that was there rather than childhood habit.
• The 2005 movie Thumbsucker by director Mike Mills focuses on a 17-year-old who has the habit of sucking his thumb. It was based on a 1999 novel of the same name by Walter Kirn.
• Walt Disney Studio's 1973 film Robin Hood portrays Prince John as an adult thumb sucker.

[edit] See also

• Stereotypic movement disorder
• Prognathism

[edit] References

[edit] External links

• http://www.ada.org/public/topics/thumbsucking.asp
• http://jada.ada.org/cgi/content/full/133/12/1610-b
• http://www.cda-adc.ca/en/oral_health/cfyt/dental_care_children/pacifiers.asp