As you have noticed, your non-clinical community service seems random, but you're trying to show some consistency by committing to one opportunity for a longer period of time. I tend to ignore activities with fewer than 50 hours.
Your clinical experience hours are also relatively low as you have mixed different opportunities (animal shelter/vet assistant, standardized patients) that don't directly help you (unless you were helping with dental work with the vet, so... there's some credit there). It's hard to discern a strong commitment to dentistry from the profile given.
Tough to say this, but it's great you have a master's degree, but it adds marginal value to your application except perhaps some delicate hand skills for fine manual dexterity but not clear with procedures that involve it. Research doesn't mean much for dental schools.
What is your purpose as a dentist? Sure, you came from a disadvantaged environment but how is that relevant to your goals as a dentist? I know you walked away from vet med, so how would you address this change?