hello doctor...my baby has completed 17 month on 23rd of May.....he has a bad habit of thumb sucking.....when he was 3 month he suck thumb when he was hungry.....then after 6 months he suck his thumb while he feel like sleeping.....now he had habit to put his thumb in mouth and suck when he has nothing to do....means all the time....plz suggest what should I do to get rid of this bad habit.....if there is any medicine then you plz give the name of the medicine....