To answer the original question, Brigham Young University (not a Jesuit school :wink: ) feeds 10 people a year into Creighton and 15-30 a year into Marquette. Based on this I would say that it isn't extremely important to have a Jesuit undergrad education, however, as other posters have noted, the schools are highly committed to certain values. Demonstrating these values assures the schools that you will be an honorable alumni and consumate professional.
I believe that these two specific schools offer wonderful dental educations, regardless of their religious affiliation.