Snaangirl,
If your school does not have a Health Professions Committee to write you a composite letter of recommendation, yes, you'll have to obtain at least three from individual science professors and/or dentists and/or other people.
Here's my suggestion: ask and obtain your letters early and ask your letter writers that as soon as they're finished, have them give the letter to you in a "SEALED ENVELOPE" and "SIGNED across the SEAL". As long as the letters are sealed and autographed by your letter writers, AADSAS will accepted as confidential.
Reason why I suggest that you collect your letters when they are finished:
1) Your writer will tend to write them quicker when you ask them to give it to you when it's finished. In my experience, when I ask my writers to give it to me, they ask, "When do you need it by" and then I would inform them, "ASAP!"
2) If you collect all of your letters, you can then send them all in "WITH" your AADSAS application materials (Official transcripts, AADSAS signature form, etc.) This way, you'll know when you send it in to AADSAS and you wouldn't have to call your letter writers every week to remind them or ask them if they have sent it yet or not!
About the sending in your letters BEFORE your application, I believe that AADSAS will not accept that. AADSAS will not start a file for you until you submitted the "ELECTRONIC" portion of it, paid your AADSAS application fees, and the AADSAS signature/paper work to them. If you send in your letters of rec to them without starting a file, they WILL loose your letters and they will not care!!!
Collect your letters, ask your writers to personally hand it to you when they're finished with it and send all of them in to AADSAS together with all the other paper work stuff. Then on the same day, "click" SUBMIT in your AADSAS ELECTRONIC application if you want.
I hope I helped!
Again, DO NOT send in your letters if ADDSAS have not received your application fee and application stuff.
