The mouth provides a baby’s first contact with the external world, and sucking is an infant’s first coordinated muscular activity. Babies even suck their thumb before they are born. The survival of a newborn baby depends on instinctive nutritive sucking, which allows for essential nourishment. Infants also engage in non-nutritive sucking of their fingers and thumbs, which provides them with a sense of well-being, comfort, and security.
Thumb sucking, however, can also have negative influences on both dental development and speech. Prolonged thumb sucking can deform a child’s upper dental arch, cause a crossbite, protrude teeth, and create an open bite. The extent of these negative consequences are affected by the duration of the habit, the daily frequency of the habit, and the manner in which the thumb is placed into the mouth.
After the age of four, correction of a thumb habit may involve using psychological and/or physical preventive measures. Evaluation by pediatric dentist may be necessary to help resolve the sucking problem. The ultimate goal is to help your child stop the habit rather then forcing them to stop sucking.