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(HealthDay News) -- Thumb-sucking is a natural reflex that allows many children to feel less anxious and more secure.
But the habit can wreak havoc with a child's oral health if it goes on too long, the American Dental Association says. Most kids stop thumb-sucking by the time their permanent teeth are ready to come in.
If a child continues to suck the thumb after the permanent teeth appear, the ADA warns it could lead to problems affecting: