Don't let what anyone said on here discourage you. I butchered the RC section equally as bad and got into many great schools including Penn, UCLA, UoP etc, and I'd say I'm doing pretty well in dental school so far.
At the end of the day, people in admissions won't just throw out your application because you have one bad score on one sub section of the DAT. As long as the rest of your application is solid, you'll be fine.
Oh and the whole "RC correlates to success in dental school" is garbage. Most people who do really well on the RC section don't even read the passages - they just skim and look for key words. Not to mention that dental school is just powerpoints with condensed information, so you don't even need reading comprehension. The people who excel in dental school are the ones with the most drive and the best work ethic.