Thanks for using my quotes regarding bicuspid extraction and I can assure you that all those statements are true from seeing them first hand in private practice. The front teeth play an extremely important role in facial beauty by providing lip support for the area around the mouth. When traditional orthodontists extract premolars to make room to straighten teeth this creates way more space than is needed so to close all the gaps, the front teeth are retracted or pulled back. Commonsense will tell you that if you have nice full lip support to begin with and when the front teeth are pulled back, it will cause the lips to sink inward creating a dished-in profile. But there are a few (VERY few) instances where bicuspid extraction is a good thing and that is in cases where the mouth is too full (very bucky). These are called bimaxillary protrusion cases and here, the goal is to make the lips less full. BTW, I have studied under the dentist whose website you provided in your post. Dr. Spahl is an excellent TMJ dentist and provides excellent TMJ treatment with emphasis on facial beauty. The pictures on Dr. Spahl's website are worth a thousand words, as the old saying goes.
functional orthodontist; treated TMJ since 1984