3rd one (enivromental science teacher) won't count either for most schools.
Almost all schools will require 2-3 science teachers with some schools being very specific (i.e. 1 biology, 1 chemistry; or 2 biology, 1 chemistry, etc.).
If you can't get enough science teachers, then it's a red flag. It can be construed as you being a bad student or desperate that you had to resort to getting non science teacher recs.
I wouldn't submit any recs from employers. This is dental school, not MBA school. DSchools don't care about your career performance in a business setting; they care about your academic performance in true science courses.