Its really hard to pin point what specialties are the most competitive for any given year. Tradionally Ortho is the most competitive followed by OMS, Endo, and then Perio. Recently Endo has become harder to get into than OMS becuase OMS is very demanding and the hours can be long after residency. But the ranks i gave u can be some what misleading. Let me explain. Most Ortho residents tend to be very homogeneous, the same. They tend to have graduated lets say top 10 out of 80 and have boards in between 92-97. Does that meen you cant get an Ortho spot if you dont have those credentials, absolutely not. There are about 260 spots for Ortho, so i doubt that all go to top 10 students. Endo is very different, most Endo residents arent very similiar. There are alot of Endo residents that did graduate top ten. There are also residents that were top 20 out of 80 who did research. There were residents who were top 35 out of 80 with research and a GPR behind there belt. Basically there are many things a student could do to increase his/her chances of getting into an Endo residency. If you want Perio do research, for OMS study hard for the boards and do alittle research. If you want to increase your chances for either of the four demonstrate an interest in that specialty, get to know the faculty that teach that specialty, and dont act arrogant at the interview. Hope this helps 
