As a Certified Orofacial Myologist, I am treating many more adult thumb suckers than ever before. My latest is a 47-year-old male who has sucked his thumb all of his life. He has had three sets of braces. His orthodontist sent him to me for treatment of a 'tongue thrust'. She didn't even ask him about his thumb being a possibility for his open bite! He stopped sucking the FIRST DAY! I don't think dentists and orthodontists think that there are adults who still suck thumbs so there are MANY who never get help. If they choose to stop, there is help available. That's what I've done for four decades!