go to metro zapata, walk up Universidad street towards the park, turn left at the park onto Oilares, go about 3 blocks on your left will be a clean, brick building/centre with a security guard and some signs about the programs they offer. just past the security guard is an open entrance with waiting room and appointment desk. This is a dentistry school, you can make an appointment and get whatever you want done for free (you pay for any pain medication they use, it's cheap). Like I said, this is a dentistry SCHOOL, so when you go in, I guess you judge for yourself if you want this person performing surgery on you. But it's free... Good Luck