I don't remember exactly but I wouldn't be worried about. I don't consider myself a good writer, but I would say I am below an okay writer. Also, my handwriting looks like a child's handwriting--I print. So, if I can do well and get accepted, you can do well too. My advice would be stay current with news dealing with dentistry and technology. As far as to prepare, use the interview section on here, and get your friends or your academic enrichment center to do a mock interview with you. Also, look at the website, see what attracts you about UB and make sure to bring that up in the interview. Get a good night's rest (I didn't), but was able to pull it off. My biggest advice: relax, ask questions, talk to everyone (the other interviewees as well), visualize that you want to go to Buffalo. Buffalo is an awesome school, the only negative is the weather.
P.S NO MATTER WHAT HAPPENS just CHILL and be CONFIDENT
I agree with what is said above. Its not so much what you write but show that you CAN write. My topic at buffalo was "Describe a book that you read recently that inspired you" or something like that. UPitt also made me do one and they said they did it because they had admitted a couple students previously who turned out to have no writing skills at all. They must have had someone else do their personal statements or something. Don't worry about it too much. The interview if definitely more important than the essay. As to that, they might be alittle rough on you but just be yourself. If you try to think and prepare too much you'll get brain-fried if you are nervous. You obviously applied to Buffalo for a reason. Let them know that and be prepared to give your definition of professionalism. Its not a guarunteed question, but it is asked alot. Good luck! and maybe I'll meet you in August!