I have a B.S. in a business field and thus I am going to contribute my two cents. My degree going to be useful when I open my own practice, at least initially, but what I have found in my seven years in the business world is that most people can pick up business concepts in their spare time, just as a dentist could learn by doing. For example, almost all of the top executives at companies are technical persons who have either enhanced their education with an MBA or have just picked up the concepts along the way. Reading a balance sheet, cash flow statements, and preparing marketing plans are all useful skills, but can be learned quickly without the aid of a teacher. Business skill, in my opinion, should be an addition to a strong technical background.
If I could do it over, I would get a degree in a science field because these classes give you a better education. They teach you how to analyze and think critically. All majors have a writing component, which is important no matter what you do. If you are really desperate for business skills, get an MBA later on (at night). An MBA is more specific and could enhance your business skills (i.e. financing/investing, etc.) at a time when you have money and can actually put these skills to good use.
Your grades will likely be tied to your interest in a subject rather than how easy it is. I graduated with a 3.6, but have a 4.0 in post-bac work. Classes like tax auditing, economics, finance, and manufacturing management are not push over classes and require studying just like biology or chemistry classes do. If you don't think you can get a good GPA as a science undergraduate, then it is equally likely that you are going to bomb out as a dental student.
