Speaking of choosing entrees, I would think that the Human Nutritional M.S. would be the most appealing of the four. The only other one that even slightly relates to humans is the Sports Medicine one (which probably has its own advantages of teaching you a lot about body movement and anatomy).
The nutritional one would give you a unique perspective on something that most doctors and dentists know very little about, but that has a huge impact on people's health and is related to things that they choose to put in their mouths and chew: foodstuffs! Since you majored in Biochemistry, it might also be the most intuitive program for you.
I guess it would depend on the types of courses that comprise each M.S. program, whether the dental schools you're interested in would be impressed. Have you considered just taking more upper-level undergrad courses for a year to raise your GPA? If you do an M.S. program, you'll have those grad school classes, but your undergrad GPA would still be set in stone at 2.8. An M.S. program isn't going to directly affect it and it may not be enough of a boost for you to offset the low GPA. Good luck!