This is exactly my issue! I have been a thumb sucker for a long, long time and even after having braces years back, my teeth have moved due to my thumb. My front 4 teeth appear shorter than my "K9" teeth and when I smile, my upper lip hides the 4 teeth more than I would like. I am thinking of getting Lumineers on the front 4 teeth. Did it at all cause you to develop a lisp?