Hi Dr. J,
Bit of a complicated story. I had extractions done from a previous treatment that never got completed due to me moving to the States. With this previous treatment I had headgear to help adjust my lower jaw forward. This along with 4 extractions U/L setup me up to be ready for treatment (which only took me eight years to restart!). What invisalign is doing for me now is widening up my (upper) arch -- already 8mm if widening completed, closing the gaps between bi-cupsid and canine where the extractions took place. Then it's pretty much moving back the outer incisors while dropping down the front. Believe me the change is already dramatic. My lowers are almost finished and look great! I'm going to put together a blog in the braces stories section soon. You will be able to see where I started from to where I currently am.