Different strokes for different folks; sounds cheesy, but that's all I could come up this late. I'm sure it's a breeze for some people and a nightmare for others, just depends. Based strictly on the amount of education required to become a dentist and the variety of skills necessary to do your job, I'd say dentistry is one of the most difficult careers you could pursue. Of course, the people who get into dental school and go on to become dentist probably think other things are more difficult.
There are a lot of people who apply to dental school and are not accepted, but don't think too many people drop out once they are accepted. I don't know statistics, that's just my subjective observation.
As for community college coursework, I'm sure you know the answer to that question. If you're aware that it's easier to get good grades at a CC, you can be guaranteed that the dental schools are, too. Try to get most of your courses done at a 4-year college/university.
Good luck!