Probably very little but you never know. I would play any card I had if I were you. It couldn?t hurt. If they donate money to the school they might have a little pull.
With that said?.I would love to go to OSU. I know 4 alumni from there. None of them have ties with any of the admissions committee. My aunt is actually very close friends with one of the faculty member there. She spoke to him for me to see if he could help pull any strings to help get me in. The faculty member went to the dean of admissions who basically said I would have to significantly pull my DAT scores up to have a chance. Bottom line, it might help you a little but if you?re not in the ballpark range for their required stats it will probably do very little. Just my opinion.
Best of luck.
As Mr. Restriction Endonuclease says, can't hurt, might help.
You can play it with this angle: If the interviewer asks you why you want to go to dental school and all that, you can say that you have had a lot of exposure to the profession since your immediate relative is a graduate of this esteemed institution, so you are familiar with the profession and would love to be a part of it for the rest of your life, yadda yadda...
This was part of the spiel I gave to NYU when I interviewed for Fall 2000 admission (my sister graduated NYUCD '00, and an uncle NYUCD '86). And yep I was accepted that year.