Are thumb sucking and pacifier habits harmful to a child's teeth? 

Early on, thumb sucking and use of the pacifier can actually be beneficial. They both serve to help the newborn strengthen the muscles needed for them to suckle and feed adequately to provide for the nourishment so important for their growth and development. Also, as the name implies, pacifiers help to pacify infants helping them to quiet themselves; the same applies to sucking of the thumb or fingers. As time goes on, however, prolonged use of the thumb or pacifier (or other oral habits) can become harmful. Prolonged use can alter the development of the mouth and jaws and impact in a negative way the position of the developing teeth.

There is some controversy as to when is the best time to stop these habits. Most children, if they are going to stop on their own, typically stop before their fourth birthday. This landmark birthday is also signifiicant because, if the habit is stopped by age four, any changes to their mouth stand a good chance of being self-correcting. Crossbites and openbites can get better on their own if the habit is stopped in a timely fashion. In order to assure that children DO stop by their fourth birthday I encourage parents to shoot for the habit to be stopped by the third birthday, affording some leeway if there are difficulties with stopping the habit. Further, to assure that they stop by their third birthday, I encourage parents to start weening their child of the thumb or pacifier beginning at about their second birhtday. Consult your pediatric dentist or pediatrician for the best ways to help your child stop. Remember to let them know if you are working on "potty-training" around the same time because this may impact on your potential success of making progress with both toilet-training and habit cessation.