Thumb sucking and pacifiers are normal oral habits in infants. They provide comfort before going to sleep and help calm down your child when they are upset. Most children stop before they get to school. However, if your child sucks strongly on a pacifier, thumb, or fingers beyond 2 to 3 years of age, it could affect the shape of her/his mouth or how the teeth line up. If your child stops sucking on a pacifier or fingers before the permanent front teeth come in, there’s a good chance his bite will correct itself, but if this does not occur then orthodontic treatment may be necessary.