Many experts say children can safely suck their thumbs or pacifiers until they enter school, but a new study published in the December issue of the Journal of the American Dental Association suggests if the behavior persists after age two, children's bite may be affected.
"Sucking is a natural reflex, which comforts infants and young children. Any recommendation to stop thumb, finger or pacifier sucking before a child is two years old would be unrealistic, potentially detrimental and unnecessary from a dental standpoint," states lead author John J. Warren, DDS, MS, of the University of Iowa College of Dentistry.
Funding for the study was provided by the National Institutes of Health. However, the study, conducted by Dr. Warren and colleagues at the University of Iowa College of Dentistry and the Tokyo Dental College, reveals that children who continue to suck a thumb, finger or pacifier past age two increase their risk of developing protruding front teeth. In addition, such habits increase the risk of an improper bite with narrowing of the upper jaw relative to the lower jaw (crossbite).
Dr. Warren's group studied 372 children in Iowa who sucked a thumb, finger pacifier, or combination thereof, from birth through age four. Each year, researchers administered questionnaires to the parents about their children's sucking habits. At the end of the fourth year, the children were assigned to one of five groups, depending on the year they stopped the habit. The fifth group was made up of children who continued to suck their thumb, finger or pacifier. Models of the children's teeth were made between the ages of four to five and certain dimensions measured. Researchers then compared the measurements from each of the five groups.
Results indicate that the prevalence of crossbite in the molar area steadily increased from 5.8 percent for children who stopped the habit by one year of age, to 13 percent among children who stopped between two and three years old, to more than 20 percent for those who continued the habit after they turned four years old.
The researchers plan to continue the study to determine if the dental condition persists after the children's baby teeth are lost. In the meantime, Dr. Warren suggests that if three- to -four year old children persist in sucking their thumb, finger or pacifier, professional assistance may be needed to correct the resulting conditions.
Note: Although the study reference above appears in The Journal of the American Dental Association (JADA), it does not necessarily reflect the policies or opinions of the American Dental Association (ADA). For information about the ADA's position on oral health issues, visit www.ada.org.
