Communication classes are EXCELLENT for dentistry and life in general. I highly, highly, highly advise an intro to public speaking course. Not only will it be a GPA booster, but it will give you great tools for success.
It's best to pick the right professor. You don't want the professor that doesn't care, but you don't want a professor who hands out As through curves and extra credit. You want a professor who genuinely loves the subject, always PhD, does research, is friendly and has good reviews, AND a professor that gives out As.
Don't think that just because it's not organic chemistry or calculus that it'll be "easy."