When it comes to thumb sucking and finger sucking, some children really do struggle to break their habit. Unfortunately, regular sucking has proven to be detrimental for growing mouths, particularly once adult teeth begin to cut through. Thumb and finger sucking put the sides of the jaw and the softer tissue at the roof of the mouth under pressure. This causes the upper jaw to narrow. A narrow jaw will prevent teeth from aligning correctly. This is a malocclusion.
All the dentists I have spoken to agree that prolonged thumb or finger sucking habits are detrimental to both a child’s teeth and their jaw. Added to this a G.P friend highlighted the risks of Paronychia. For parents of thumb sucking children, the outlook might include some rather unpleasant future orthodontist’s bills too.