In my opinion, Endo is much harder to get into right out of school. After a GPR your chances in endo are much better. Many/Most schools will not accept your application unless you have done a GPR or have at least 2 years private practice experience. I have met numerous general dentists with 5+ years of experience who have applied to endo for several consecutive years without luck. It is darned competitive indeed.
Ortho on the other hand, is relatively easy to get into right out of school and a GPR probably makes no difference (with the exception of certain schools).
Both programs value research, board scores and academic standing. I think that you have a great shot if you are top 5 in your class, good chance if you are within the top 10, and poor chance if your class rank is any less than 10 for either endo or ortho.
