Terry,
first, i chose to be a dentist over md because of the length of time of studying.
second, dentist do more hands-on work unless you are a surgeon, and i thought i would enjoy that more.
third, the money, the quality of life, and the hmo and the lack of uncertainty in u.s. healthcare services weren't as attractive as an MD.
after my undergrad, i was in a phd/ms program and "wasted" 2 yrs. i wanted to come to dental school, do well, and start making money and enjoying life. if i had gone to med school, i would have strived to be an orthopedic surgeon(cuz i think the tools are cool.. haha) i think orthopedic surgery residency is 6 yrs after med and very competitive.. anyways i'd rather be a general dentist than a internal, family medicine guy who sees pt for 15 min, charge 50 bucks and gives Rx for cold pills.
associateship is where a dentist graduates from a dental school, or comes out of a specialty/residency and decides to work for another dentist. hence, associate, instead of partner..
you shouldn't be worried about money as a MD or dentist in ideal, but as we all know, all these schools cost an arm and a leg. choose wisely, and choose what you will enjoy for the rest of your life. i think general dentist makes more than family med. but if you look at specialists (MD), they make even more. apparent lack of dentists?? what part of the us are you in? let me move there.. hahaa.. i think there are more.. if not same.. but some of the dental schools closed in the 80's due to the high flying economy(professional schools don't have any applicants), and the ADA was better at closing the faucet in turning out dentists where as AMA increased turning out MD cuz residents(slaves who are worked for 5-10yrs depending on residency and including fellowships) make heck of lot more money for the hospitals.
a dentist can practice right after graduating from dental school. some feel they are confident enough to see patients in private settings, others choose residency to specialize in ortho, pedo, perio, etc.. but others go to advanced general dental programs to work for hosp or dental schools.
as for me, i am gonna grad and start yankin' on ppl's teeth when they gimme the license to practice!
hope that quenches your curiosity!