This is unacceptable in the 21st century. They ought to just be able to shine a laser around my mouth, build a 3-D model, and work from there. If anybody knows of a company building such a thing, I'll gladly scrape up some cash and make an investment. Heck, a donation.
Edit: Like this: http://www.ddsgadget.com/2006/04/3d_digital_imaging_to_revoluti.html
Though I have to say the actual casting process was better than the mashed-potato gunk that they used when I had my braces. I've just gotten wimpier in my old age.