Thumb sucking affects dentition

Children who continue to suck their thumbs or fingers or use a pacifier after the age of two may be more likely to develop an overbite i.e. protruding upper teeth. The overbite can also interfere with the child's ability to form words correctly. The researchers from the University of Iowa studied non-nutritive sucking among 372 children. The study included children who sucked their thumb/finger or used a pacifier from birth. Parents answered questions about their child's sucking habits and the children were put into one of five groups based on when they had quit this habit. Dentists examined the children and made models of their teeth between 4 and 5 years. The models were measured for dental arch parameters (including arch width, arch length and arch depth) and assessed for overbite and crossbite. Then they compared the dental arch and occlusal conditions. The study found that most children sucked a finger, thumb or a pacifier at some point. Nearly one third of the children had stopped sucking by the age of 1 year, and about 16% continued to suck a finger or pacifier at age four. Kids who used a pacifier or sucked their fingers or thumb by the age of 4 to 5 were more likely to develop protruding front teeth and an irregular bite, compared with their peers who gave up the habit at an earlier age. Previously, sucking habits were not thought to be very important until children reached the age where their permanent teeth began to erupt. It was believed that once the habit was stopped, the conditions (crossbite, protruding upper front teeth) resolved by themselves as long as the permanent teeth weren't involved. However, this study found that more children, who persisted in sucking their thumb, fingers or a pacifier, developed protruding front teeth and that this did not resolve by itself, even 2 to 3 years after giving up the habit. The findings suggest some potential harm in continuing habits beyond two years of age, with greater risk of developing occlusal problems with longer sucking-habit duration, particularly habits persisting to four years of age or beyond. Therefore, to satisfy infants' need for sucking while minimizing their risk of developing dental abnormalities, the ideal age for discontinuation of nonnutritive sucking habits may be around two years. Relatively little harm occurs if such habits are continued to three years, so that early dental visits should provide parents with anticipatory guidance to help their children cease such habits by three years of age or younger. However, if the child's habits persist by the time he or she is 3 to 4 years of age, professional assistance in habit discontinuation may be warranted to minimize the risk of developing malocclusion. It may be prudent to revise suggestions that sucking habits continued to as late as 5 to 8 years of age are of little concern.

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