Maybe I can chime in here with something, being a History major and all. I have not been accepted to dental school yet, but I think I stand a pretty good chance at it. Balancing the different course loads can be a bit of a challenge, but it is not impossible by any means. I know that you asked about if it takes longer to graduate, but I would like to answer the better question is that does being anything but Bio or Chemistry major hurt you in the eyes of the admissions folks? I dont think it does. Your pre-reqs will give you a solid science foundation and enough exposure to science to show that you will be able to handle Dental school. Your humanities classes will show that you are a well rounded individual with eclectic interests and such. Is that an advantage? I think so. To me a Liberal Arts degree with the science pre-reqs is THE perfect way to get a solid education in many different areas. And in the end, that is what adcoms are looking for. Of course it doesnt hurt to have a good gpa and a rocking dat score to boot.