To my knowledge no medical or dental school (or any professional school) has a "formal" way of noting a disadvantaged situation. I must respectfully disagree that some schools merely look at your numbers and other schools look at your entire application. All schools look at the entire application. Of course, every school focuses first on GPAs and DAT scores. I see no exception. If you apply with high stats, they may not care about the rest of the application as much. If your stats are very low for that school, no amount of extras will help. However, the average applicant for any given school will have similar GPA and DAT scores. That's when these extras become increasingly important. Naturally, there are schools that are not as competitive and do not require as high a GPA/DAT compared to other schools. However, the same applies to these schools. Out of there applicant pool, they accept those with the highest numbers without much thought. They reject those with the lowest numbers regardless. They're left with the rest (the majority of apps) that have similar numbers and that's when extras become increasingly important. But I highly doubt that any one school cares more about disadvantaged students than another school. All schools are interested in the best students they can get. However, when schools compare applicants, I think that what you say in your personal statement and interview can be influencial.
If I were you, I'd include my feelings about being disadvantaged in the personal statement. Just be sure to describe it as something that has challenged you and you've overcome. Be careful about using it as an excuse. For example: Don't suggest that because I'm disadvantaged I didn't do as well in college as I hope. Describe it as having difficulties or barriers that you overcome and were able to keep the hope of becoming a dentist alive.. etc etc. If you didn't do as well in college as you hoped, but you describe the obstacles well, the admissions committee will put two and two together and realize it's understandable you didn't make an A+ in all you classes. Hope this helps.
