Dileep:
Everyone has a weakness on their application, yours is your gpa. However, it doesn't matter what your weakness is but how you represent and present yourself during the interview. PENN is a very mysterious school because it does not look only at Numbers. If they get that "vibe" from you that you will be an asset to their program they will take you hands down.
Like I said in the email I sent you, read up on their community activities. PENN is known for its community dentistry. PENN has 6 Private Care Clinics (PCU's) they have a Mobile that goes to different parts of Philly to help disadvantaged kids.
Also, your teaching experience will blow your competition outta the water. There is a huge need for academic motivated dentists. You have potential. You taught. Currently there are 400 openings for professors that are unfilled. You have experience and you telling them that you would like to teach would be taken more seriously than soemone who does not have teaching experience.
Maybe it is good you have a low gpa, that way you can be a little nervous. Much better than being too over confident I think.
Good luck to all who have interviews at PENN.
Regards,
DesiDentist