I'm sorry, but this is your conclusion based upon that data? Yikes.
How on earth do you look at that data and extrapolate that there is significance in the claim of a "50% increase" in enrollees with Masters degrees? And even if that information were true, how could you ever present causal evidence that the degree is needed for matriculation. Maybe - if the original numbers were 2 or 3 students per class each year... a jump to 5 or 6 would be your 50% increase. But so what? Therefore, you are more competitive with an MS?
The fact of the matter is that if you needed a Masters degree or any advanced degree to be more competitive as a dental school applicant, a large percentage of each class would be filled with students with said credentials.
At UNC for example - of the 81 student each year - around 5 of those students have a masters degree or other advanced degree. This is is a minute component of the class. Moreover, of those students, the vast majority earned their advanced degree well before ever deciding to enroll in dental school. By and large, Dental School was an afterthought - it was not completed as a proactive attempt to increase competitiveness of one's application.
First of all. You should always direct specific, personal questions to admissions officials. No one will be able to give you catered advice based upon a tidbit of your profile.
Are there students every year that apply with Masters degrees? Yes. Are there reapplicant students who gain admission after pursing advanced education? Yes. But to say that these tracts are the norm or anywhere near the realm of necessary for admission is absolute hogwash.
The overwhelming majority of dental student classes are filled with 4-year Bachelors-Degree students.
Pursue additional education because you are passionate about the subject - not to simply increase chances. If you are not truly passionate, I would think you will find difficulty boosting your GPA over an undergraduate record, especially in lieu of increasingly difficult and demanding graduate level courses. Moreover, you would be extending the time before you are completely done with dental school and adding additional education debt.