I am currently in the MABS program in IL, the program will definitely prepare you for dental school. The MBS program is much easier than the MABS (1 yr) since the course load is much lighter. I think with the MBS program, you will have a better chance of getting in since most of the students in the 2-yr do get in. From the MABS, they don't give us exact numbers, but usually 1/2 get in. Since you'll be doing research in the MBS you'll get to know faculty and getting a letter from them will carry weight. You can check the block schedule at
http://www.midwestern.edu/downers-grove-il-campus/block-schedules.html and check the schedule for the entire year. It's expensive, but I think it is a good option if your app needs a boost. Let me know if you have any specific questions.