If you're looking to specialize in dentistry, the response looks like this: "Study hard, get excellent grades, stay near the top of the class, and smoke the boards."
Specialty residencies are much less prolific in dentistry than in medicine, and so matching is much more difficult in our field. A very solid majority of dents go on to become GPs.
Something that tends to fall between the cracks in a lot of people's minds, however, is that a GP is as entitled to perform "specialty" procedures as a specialist. Just take lots of ConEd to stay current with techniques and procedures, and be sure you can perform any procedures to standard before you agree to them.
Most of the high-end GP salaries everyone slings around on these boards come from dentists who are confident and competent to perform a lot of specialty procedures (endo, fixed prostho, etc) in-house to earn the income themselves, rather than farming the cases out to specialists. In the end, it's just like any other profession--you can skate by on bare minimums, but the more responsibility you're willing to undertake, the more success you'll generally encounter.