My pleasure youngmc27!
There are typically two or three ways to receive a loan repayment contract. The first is thru the National Health Service Corps, website
http://nhsc.bhpr.hrsa.gov/. This is a federal program, and on that website you can do a search for job opportunities by state and by occupation. If you find a job you are interested in, there is usually contact information listed. Call the contact listed and see about setting up an interview. They will probably want you to send a cover letter and resume as well. If things go well and you are offered and accept the job, you can apply for loan repayment (look under the application tab on the website). Keep in mind that this by no means guarantees you loan repayment. As it was explained to me by a staff member at the NHSC, they will go thru all the applications and begin awarding the loan repayment contracts (usually 2 year commitments, $50,000 total) by looking at the Health Professional Shortage Area (HPSA) score and awarding from the highest scores down. So, if the job you are interested in has a high HPSA score, you are more likely to be awarded a repayment contract. Get in touch with someone at the NHSC for more info. They will probably be able to give more specifics about the program.
Another way to receive a loan repayment contract is directly thru your state. Some states offer loan repayment programs, which are similar to the NHSC program. The criteria may vary a bit from state to state, but where I live I just had to be working full-time at a community health center in a health professional shortage area. I would suggest contacting your state's primary care association, or it's department of health and senior services. Just give them a call and ask about loan repayment, if they offer it etc. If your state has such a program, the contracts will most likely be awarded in a similar fashion (highest HPSA scores down).
A third way is thru the Indian Health Services, website
http://www.ihs.gov/. Of course these jobs are only available in states that have a native american population (ie. California, New Mexico, Arizona, Oklahoma, Alaska etc.) I don't know as much about this program, but I would suggest exploring the website and giving them a call. Thru this program, I believe you will be working on a native american reservation, at a public health clinic that only treats this population. I think this program is really cool, so if you live in a state that qualifies, I would recommend looking into this. I knew someone who did this program in New Mexico, and she really enjoyed it. I believe she commuted to the reservation (maybe a 40 minute drive to and from work).
Also, don't hesitate to talk to your dental school's public health director. He/she will surely know more about what programs are offered in your area that I do, and offer some suggestions of their own. They may also be able to get you in touch with some people who have graduated from your school and who are working in one of these programs.
Hope this helps! Good luck with school.