Yes, it is ok to submit extra letters of evaluation.
AADSAS only holds 4 letters of recommendation; the rest must be submitted via a third party directly to the school. It is best to use the 4 spaces allowed by AADSAS for 1 dentist, 2 sciences, and 1 non-science.
Most schools require 3 letters of recommendation: 2 science + 1 dentist
However, some schools (such as UNLV) require 4: 2 science + 1 non-science + 1 dentist
Further still, some schools (such as UMB) require 3 specific letters: 1 biology + 1 chemistry + 1 dentist.
Also note that some schools (such as USC) do not accept a science letter provided by a professor from a non-lecture course such as an upper division biology laboratory course.
In general, when asking for letters of recommendation, an applicant should plan on asking at least 2 science professors and 1 dentist. In addition, applicants should contact the admissions departments at the schools he or she plans on submitting an application to and ask if there are any other school specific requirements before submitting the AADSAS application.
A Big Note: Proceed with Caution
When submitting extra letters of evaluation the applicant should use his or her discretion. Extra letters of evaluation can serve as a hindrance or distraction to admissions committees, and should only be submitted under three conditions: one, the author holds a prominent position (ex: the Gov. of CA or the President of the ADA); two, the author is an alumni of the institution; three, the author and applicant have an extensive and academically relevant relationship that revolves around research or the creation of a project (the author should have a PhD or other authoritative degree).
An extra letter of evaluation should not come from:
1. Another dentist
2. Another teacher
3. A friend, colleague, or family member
