Yes to a certain extent. If you have a low GPA and not a lot of extracurriculars to make up for it (research, clubs, service, etc.) then you're at a disadvantage. However, being peds myself, if you have good experience after dental school (GPR, private practice that sees a lot of kids) then that would make up for the lower GPA. For peds, the more experience you have with kids, the better,