Dental School?

I'm starting my fourth year in college. The first year I took some classes which I didnt need so basically just 3 years of college lol. I wanted to get into dental school, but not sure what classes I need to take. I'm 22 and I've heard dental school takes 4 years, so I don't want to waste anymore time. So far I have taken up to cal, bio 1 and 2, chem 1 and 2, all history and government, psychology, sociology, speech, economics, ethics, and physic. My gpa right now is 3.9, however I'm having a hard time in physic. I was wondering if I make a C or B in physic would it still look good when I apply for dental school. By the end of next semester I would have 66 hours, and I think dental school require 90-100 hours. I wanted to ask what major would you guys recommend, and any community service or other stuff I need to do to be prepare.

Dental School?
I am a 1st yr dental student... you MUST have 1 yr of gen chem, 1 yr bio, 1 yr organic chem, and 1 yr physics. some schools require biochem as well and most recommend anatomy and physiology. Dont waste your time by applying without 1st having or going to have a bachelors degree before entering dental school.... you wont be accepted. Also a B or C in one class wont hurt you too bad... as long as your overall GPA is above a 3.6 or so i'd say you're sitting pretty well. They look at Science GPA too so keep that in mind (includes physics). Biology is the most common major but diversity is background is encouraged (my engineering friend got in more easily than i did with a bio background) and all community service of any kind and science research is highly encouraged to be competitive. start studying for the DAT. you must do well on that to get in (20+). good luck. it is a long hard process.