In 99% of cases, yes you will need two letters from science professors. It is very likely at least one (most likely more) of the schools you apply to will need multiple science letters. The article simplifies the whole process by just assuming you will need two. If you have a list of schools you plan on applying to, you can determine how many science letters you need in total using this list. Keep in mind this resources is from 2010-2011 so it is advised to double check with the school directly as well. For example, if you plan to only apply to three schools (just simplified for the sake of the argument):
- UCSF
- 1 science letter
- 1 dentist
- 1 any
- Source: http://dentistry.ucsf.edu/
admissions/dentistry-dds/ application-procedures
- UCLA
- UoP
- 2 science letters
- 1 dentist
- Source: http://www.dental.
pacific.edu/Academic_Programs/ Doctor_of_Dental_Surgery/DDS_ Program_How_and_When_to_Apply. html
In this case, applying to UoP means you must have 2 science and 1 dentist letters in order to qualify for all three programs.