Thumbs up...and in

Feb. 1, 2001
A group of thumb-sucking adults proclaims the habit is a 'cheap, convenient, and effective way to calm oneself.'

A group of thumb-sucking adults proclaims the habit is a 'cheap, convenient, and effective way to calm oneself.'

Is it right for us to counsel against thumb-sucking, particularly when it impacts dental health?

Good grief! Did you know Linus Van Pelt has been sucking his thumb and clutching his security blanket in the comic strip "Peanuts" for nearly 50 years? I wonder - did anyone ever put bitter medicine on his thumb to try to get him to stop? Was he ever teased by his peers about his very public habit? Did his dentist lecture him on the damage this can do to his mouth? Of course, Linus just wouldn't look right somehow if he gave up his famous habit. But many parents (and orthodontists) are adamant that thumb-sucking is detrimental - babyish at best and an abomination at worst. What are the actual risks - dental and otherwise - associated with this habit?

Sucking appears to be one of the more basic reflexes of humans. Ultrasound images have proven that infants suck a finger or thumb in utero as early as 18 weeks of age. Once born, an infant who fails to suck fails to thrive. Studies confirm that most children used some form of supplemental or non-nutritive sucking from birth to about age two. Many children spontaneously cease the habit between ages 2 and 3, but some continue thumb- and finger-sucking, even through early childhood.

Thumb- and finger-sucking habits have been studied for many years to discover why children do it, as well as why they appear to be so calm while doing it. Dr. Douglas Woods, an assistant professor of psychology at the University of Wisconsin-Milwaukee, said that there is no certain answer as to why children suck their fingers or thumb. "It could be an attachment issue or may alleviate boredom, and, since it tends to happen during a child's quiet time, it appears to have a soothing effect," he said.

The feelings of warmth and security seem to relieve stress and bring on a near meditative state in the child. Dr. Patrick Friman, an assistant professor of clinical psychology at the University of Nevada, has studied thumb-sucking for more than 15 years. Dr. Friman likens it to a "safety valve" and is reluctant to take it away from the child unless it is harmful. So with our stressed-out, youth-oriented culture, why is there such a social taboo against thumb-sucking? Why do parents go all out and declare war on the thumb-sucking habit?

"I suppose it's because it looks bad," said Dr. Woods, "and parents criticize it. It's certainly a common behavior and nothing out of the ordinary; a lot of kids do it. Besides the malocclusion issues, the idea of it being distasteful is a social phenomenon."

Substituting a pacifier is often suggested as an alternative to a finger or thumb, mainly because it can be removed from the child when it's time for the habit to end. But pacifiers appear to cause many of the same dental manifestations in children as do finger- and thumb-sucking. Pacifiers also can lead to shorter sucking durations, which can increase the number of feedings an infant will need. Studies show that pacifiers used for encouraging sleep can lead to increased occurrences of acute otitis media (ear infection). Pacifier substitution to prevent development of a finger habit works quite well for some children, but studies indicate a thumb or finger habit may suddenly resume when the pacifier is removed.

The risks of thumb-sucking

When should a parent become concerned? A thumb- or finger-sucking habit prior to age five usually is considered benign by most psychologists and dental professionals, since the permanent dentition has not yet erupted. But after age five, the experts' opinions are mixed. Most see thumb-sucking as a "child" issue, not a parent issue. But risks must be considered.

"If the thumb- or finger-sucking habit becomes chronic (defined as digit-sucking in more than one environment) after age five," Dr. Friman said, "there are several risks involved." He cites:

  • Social risks if a child is observed thumb-sucking by his or her peers.
  • Poisoning risks if a toxic substance is on the child's hands.
  • Malformations of thumb or finger caused by prolonged sucking.
  • Dental problems.

Social risks can be significant if a child is thumb-sucking in public. In a study published in the Journal of the American Academy of Pediatrics in 1993, Dr. Friman observed first-grade schoolchildren who looked at photographs of children sucking their thumbs. Later, photographs of the same children were shown - this time without sucking their thumbs. A significant number of schoolchildren said that the children shown while thumb-sucking were less intelligent, unhappier, less attractive, less likable, and less desirable as a friend, playmate, classmate, or neighbor than the same children shown while not sucking.

Poisoning risks, while not very common, are present because the primary route of childhood poisoning is hand-to-mouth behavior. Malformations of finger or thumb can range from nail infections to bone-development deviations that actually cause bending or angulation of the digits. A callous often forms on the base of the digit where the lower teeth rest on the thumb or finger. A quick indication of which digit is being sucked is an exceptionally clean thumb or finger and a reluctance to use the digit or get it dirty.

The duration, frequency, and intensity of the sucking habit, as well as the placement of the digit in the mouth, determine the dental effects seen clinically.

The dental risks are well-documented: palatal arch distortion (which can lead to cross bite and/or narrow, high palatal vault); anterior open bite; maxillary protrusion; mandibular incisors pushed lingually (the sucking action pushes the posterior teeth in toward the tongue); unbalanced orofacial muscles; and tongue thrust. The sucking forces are strong enough to displace teeth and distort growing bone. Dental literature reports that if the habit ceases by age six, the dental problems usually correct themselves spontaneously. Some children continue to suck without obvious dental implications because of finger or thumb placement, as well as low frequency and/or duration.

However, many finger- or thumb-suckers require orthodontic intervention. Generally, malocclusions due to thumb- or finger-sucking cannot be corrected if a child continues the habit. So if children are harming their dentition by thumb-sucking, how can we help them stop? Like most other habits, psychologists claim sucking habits can be stopped if the person is motivated to give it up. So the first step is the child's desire to quit.

Dr. Friman said, "We always recruit the child to work on the problem, not because an adult has imposed a moratorium. When adults push, it appears to exacerbate rather than improve the situation. A verbal comment usually has a barb to it, which is hard for a child to remove. Kids don't always know how to answer back. And if parents try to help in a critical fashion, a child may not forget what they say."

Dr. Friman suggests that if there is clearly a risk factor to the child, he or she should quit. But he also recognizes that people have lots of little, minor habits. Thumb- or finger-sucking could be just a private habit they do to help themselves fall asleep, for example. "It can be just a private thing that the world doesn't need to know about," he says.

For those who want to quit, methods that often work include behavior modification, alternative activities, and various barriers that interrupt or mute the pleasurable sensation. But not all methods work on every child, and consistency plus incentives along the way are important. And no child, according to Dr. Friman, should be expected to give up a habit "cold turkey" unless it's harmful. And the "harm" done by thumb-sucking may be a subjective observation.

One group that believes children should be allowed to continue thumb-sucking is, interestingly enough, a group of thumb-sucking adults. According to their Web site, thumb-sucking is a "cheap, convenient, and effective way to calm oneself or to achieve sleep regardless of the situation," as well as provide "an easy means of tension relief. It's essentially harmless and doesn't interfere with the rights of others, like smoking does." While these adult veterans of thumb-sucking are not advocating public thumb-sucking, or whenever the urge hits, they are questioning the notion that thumb/finger-sucking is somehow a bad thing to be doing.

The Web site noted, "Unless there are some real and serious health concerns, stopping just because someone else thinks you should stop or because you think something is wrong with you merely because you thumb-suck are reasons you should give more thought to. Why should someone else's values result in you feeling bad about a harmless, gentle habit that you enjoy and need and has some real benefits to it?"

Many adults who claim to still suck their thumbs have written to the Web site about the pain and trauma they feel they endured when being forced to give up the habit.

In a "Peanuts" comic strip published on May 21, 1960, Linus Van Pelt declared that there are "two classes of people in this world violently opposed to thumb-sucking - dentists and grandmothers." With additional research into the psychological benefits and social stigma of thumb-sucking, the possible dangers of being forced to stop, and the dangers of not stopping, maybe some dentists (and dental hygienists) will no longer be found on Linus' list, but will consider the consequences more carefully. But the debate about whether to stop the habit or not will have to be settled individually, one child at a time.

Some Web sites that contain more information include: (American Academy of Pediatric Dentistry); ("Helping the Thumbsucking Child");

Cathleen Terhune Alty, RDH, is a frequent contributor to RDH. She is based in Clarkston, Mich.

Safe use of pacifiers

Guidelines from the American Academy of Pediatric Dentistry include:

  • Never tie a pacifier around a baby's neck. Between 1985 and 1990, the U.S. Consumer Product Safety Commission received reports of 21 strangulation deaths that involved pacifiers tied around a child's neck.
  • Select a pacifier with sturdy, one-piece construction, made of nontoxic, flexible material with an easily grasped handle.
  • The pacifier should be too large to swallow, have a shield or mouth guard that can't be separated from the nipple, and two ventilation holes.
  • To ensure that a piece of nipple can't break off in the baby's mouth, the nipple should be intact without holes or tears. Parents should pull on the nipple to test it, and replace the pacifier when the nipple shows signs of wear.

What works

  • Enlist the child's cooperation first, then give him or her assistance by working to mute the pleasant sensation.
  • When the urge to thumb- or finger-suck strikes, change the habit by having children do something else (clench their fists for one minute, for example), which is called an alternative competing response. Offer social support by praising children when they focus on the alternative response. Instead of emphasizing the negative behavior when backsliding (saying, "Don't suck your thumb!"), redirect children to do the alternative response (saying, "Now is a good time to focus on your hand clenching.").
  • Disrupt the sensation with a surface barrier (for example, Band-Aid, bitter liquid, sock, etc.), plus a daily incentive or reward for compliance.
  • An Ace bandage technique serves as a reminder. Wrap an elastic Ace bandage snugly from mid-arm to mid-forearm on a straight arm. When children bend the elbow to get thumb or fingers into the mouth, the gentle pressure removes the thumb as they drift off to sleep or reminds them not to put their fingers or thumb in their mouths.
  • Some children choose to suck with an object, usually something soft that is stroked or manipulated while sucking. Often the sucking habit can be broken by removing the object from the child.
  • Some dental appliances (although uncomfortable) can deter the habit.

What doesn't

  • Teasing
  • Ranting and raving
  • Belittling
  • Scolding and threatening
  • Habit-cessation techniques on a child suffering from recent emotional trauma
  • Saying, "I'll buy you a new bike if you don't suck your thumb for a month."
  • Tying a child's hands to the bed