Hi...
I am in my first year of dental school. During the end of my undergraduate education I took it easy and found many ways to justify it. If I was in your position, I would take as many biology, biochemistry and science courses as I could possibly take. Hell, take biochemistry again, just to get more familiar with it.
If you are accepted into dental school and don't need to worry about your GPA, just take the classes and do enough to pass. The extra exposure to different science courses will only help, even if you do the minimum to pass.
Either way you go, dental school will be tough. After our mid-term exams this quarter I spoke with many of my classmates and they said that they knew answers to several of the exam questions as a result of what they learned in undergraduate, not from our dental school lectures. Many went on to say that they would have been screwed if it weren't for their previous exposure to the material.
Then take the summer off and play.
Just one opinion among many, but I wish I would have taken MANY more science courses. Best of luck my friend!
-DM