From what I've observed, when schools say that your major doesn't matter, they mean exactly that. I am a music major (piano performance), and I am extremely pleased about my choice to do that. My feeling is that it really adds some depth to your application and sets you apart from the typical bio/chem majors. I interviewed at four schools and, invariably, the interviewers wanted to talk about music. They asked about my favorite composers, my activities within the department, music jobs I've had, etc. In fact, two of my interviewers were music majors themselves in undergrad!
There are more perks to majoring in a liberal arts discipline than just having something to talk about at the interview. If you choose a discipline that you like, your cumulative GPA will surely thrive. Not to mention, you might just have a little <gasp>...
fun... during undergrad.
You have four years of dental school to knock yourself out with science. If you have an interest in something outside biology or chemistry but still know you want to go into dentistry, take the plunge and major in it.
