Honestly it depends----I have a friend that was in a similar situation. (MS chemistry) She had a great grad gpa 3.7 and ok college 3.4. So grad helped her in the sense that she demonstrated the ability sustain a good gpa during rigorous schooling.
As far as specializing or being a better candidate for a specialty position----very unlikely. You will need so much more than your previous background. Such as: a great board score, good recommendations, some extracurricular activities and high class rank (if calculated) to land a specialty position. Throw all your background stuff away and focus on being a top dental student-----I promise you the competition will be fierce for the top specialties (heck almost any specialty) and a MS will really mean nothing if the fore mentioned aren't met. Want an advantage ----get published during your dental school years in a peer-review journal by doing some outstanding research, hit 90+ on your boards, befriend some good professors, and get great grades. If it comes down to your MS degree to help you get into a specialty program -it would rank in importance near the size of your feet
Good luck in school, don't worry about specializing too much this early---it's nice to have an idea but there is some much to learn (like waxing #30
) it's more important to get great grades-----otherwise, everything else is for naught.
Best of luck