Don't be silly :-)
How much do you think a surgery would make per dentist?
They do say a dentist will never go broke practicing dentistry. :-)
My point was it is possible, not even that difficult to open a small business and compete on income with a dentist. I didn't mean to say that everyone does but I think a reasonable well run business would. The problem with dentistry is the dentist has to be there to do the work. Most businesses are more open to expansion, once a dentist gets to 40hours a week full time that's pretty much where it stops. Also, to be fair and make an "on average" comparison you should include the la pochettas that started small but now make millions.
Michael