I agree with the above poster. If a B+ is considered a good grade to you you likely have more problems with your application and career path than retaking organic chemistry. I recommend you evaluate your GPA, science GPA, and re-take courses as needed. If you're unable to take classes at your university try to see if you can be a transient student at another university. While it may be more convenient and cheaper to take the cc route, community college will not prepare you for dental school or the DAT as well as a university and adcoms will look down on you for taking said classes.
You should be sure to preform on the DAT. You can make up for a low GPA, but keep in mind that phase 1 of admission process is a numbers game. The highest DAT and GPA get selected for interviews.
Biochemistry and organic chemistry have similar concepts, but they are still different courses. Some do well in gen chem but do poorly in organic chem. Some do poorly in precalc and do excellent in calc. Some do poorly in history but excel in political science courses. It really just depends.