Sarah Hudson recalls slipping into a bathroom stall in elementary school at anxious moments to do it. She kicked the habit in childhood, but peering into a mirror today, she still feels a bit self-conscious about its lingering effects on her smile.
Nikki Martin says it, coupled with a satin-edged blanket, is a part of her 5-year-old daughter's daily bedtime routine. Martin said she knows it's a habit that has to stop soon.
"We have been letting it slide because it makes her so happy," said the St. Paul mom.
The urge to suck one's thumb or finger is a survival skill that starts at birth. But at about age 5, when permanent teeth start coming in, it's time to put an end to the habit, dentists say.
Nearly one-third to half of all preschoolers suck their thumbs. The number falls to about 6 percent of 7- to 11-year-olds. But those who don't or can't quit find that thumb sucking can become embarrassing, disfiguring and expensive. Fixing the effects of a prolonged sucking habit often requires a full mouth of braces, costing upwards of $5,000, and may not completely reverse the damage.
"When you continue sucking beyond the first year of life, it more generally becomes a habit and affects the position of your teeth, the shape of the roof of your mouth or your palate," said Twin Cities pediatric dentist Dr. Teresa Fong, also an adjunct professor at the University of Minnesota. It can affect speech and tongue position, too.
As children get older, they realize that thumb sucking is something they shouldn't do and they may become secretive about the habit, hiding it from friends. Numbers of adults who suck a thumb or finger are harder to discern. Many don't disclose it to health care providers.
Bloomington speech and language pathologist Jennifer Connelly said that one in five of her thumb-sucking patients is a teen or adult. They often come to her for lisps, tongue thrusting and other oral issues but she soon discovers that thumb sucking is the underlying problem.