Well your goal is to get into dental school. So if there is a chance these calles would decrease your science GPA than I wouldn't, however if you feel you can do well in them than by all means pursue it.
I can't remember, but don't some school require biochem?
Some people may say that these classes will prepare you for dental school, however if you do poorly and these classes exclude you from getting accepted than they were worthless. Everything you need to know you learn in dental school.
Hope this helps.