How does the match work if you are interested in more than one specialty? If you applied to more than one type of program, would the directors of those programs have anyway of knowing that, and therefore consider not as good of a candidate because of this? Has anyone out there tried this? How did it work out for you?
Here are some technical answers:
Applying to more than one specialty changes the match, depending on what specialties you are referring to. Ortho is Phase I of the match and that match occurs a full 2-3 months prior to Phase II of the match (where pedo, OMS, GPR, and AEGDs match).
You can submit as programs on your rank list as you want to, and those can be any combination of programs. In short, you submit one list with all your programs on it.
If you are applying to ortho as one of your specialties, then you would be matched in Phase I and the Phase II wouldn't apply.
For Prosth, Perio, Endo, you don't participate in the match. If you accept a spot at one of those programs, then you would drop out of the match.
Now, here are some realistic answers: you'd be crazy to apply to multiple specialties. If there really are that many areas of dentistry that you can see yourself enjoying so much that you'd love to practice them for the rest of your career, then you should do general dentistry (with perhaps an AEGD or GPR first) and limit your practice to those areas that you love.
Each of the specialties requires a different mentality, and typically a pediatric dentist would make a poor oral surgeon and vice versa. I think you'd be doing yourself an injustice to apply to more than one specialty. What specialties are you considering?