I've been reviewing personal statements and I want to write some advice:
1. Don't use events in your life for pity to get into school. It reflects poorly on you and I'll assume most Adcoms have a decent head on their shoulders and look past that.
2. Don't justify yourself in your personal statement. If you had terrible grades don't mention them. This is a chance for you to show your personality, passions, and why you picked dentistry.
3. Don't list off your activities in any manner. If they aren't core to your statement, take it out.
4. Have a "thesis statement" that really answers the question why dentistry. It helps your essay seem developed and puts everything in a cohesive idea.
5. Having a theme across the board helps your statement.
6. Emotions are key. They help you form a connection with your reader. So when that reader goes to the rest of the readers and wants to fight for you, they will.