That is a good list, and mirrors my LOR line-up. Creighton requires one from a liberal arts professor and they state that information in a small section of their site. Carefully research each school as each one varies in what they seek. In my opinion, having a LOR from a non-science professor is a great idea. While science professors can discuss your aptitude for science courses and guage your future performance in dental school, a non-science professor (one that you may have gotten to know and can dish up some positive anecdotal tid-bits) is sometimes better positioned to speak of your ability to function in other capacities: i.e. deal with ambiguity, relate to the culture and community at large, - things that you will need to function as a professional and things that dental schools can't really teach or give you. Such a letter might really make you stand out and seem less of a number and more as a person patients will relate to and trust.
