For either medical or dental school, you are given a fixed deadline, usually a month after the notice of your acceptance, to pay your deposit for holding your seat. For medical schools, that deposit costs $100. For dental schools, it's over $1,000. By enforcing a shared acceptance date on Dec. 1st (or Dec. 3rd), dental schools would not financially burden the applicants to pay for every deposit to every school they interviewed at and were accepted to, including the ones that are not their first, second, or third choices.
Here's a hypothetical example, say the system were set up like medical schools are and schools could send acceptances whenever they wanted but you had to pay for deposits that cost $1,000, not $100, and you still had to pay the deposit before 30 days or else your seat would no longer be held for you. If you have not heard back from your top choices, you would be like most reasonable applicants and want to play it safe by paying for every deposit to every other school that you did hear back from. But the problem is that a few acceptance and a few deposits can quickly cost thousands of dollars. For that reason, it is not set up that way for dental schools and ADEA spares us by holding off all notices of acceptances until after Dec. 1st or 3rd.
I think we should be notified the way medical schools notify their applicants. If we wanted to be notified ASAP like medical schools, we'd first have to reduce the deposit costs by a factor of ten.
