Temple Dental school is right on the Broad (also known as 14th street) street subway line. You do not want to live near the school, but you do want to live near the subway line to get to and from school. Driving is an option, but parking is insane in Philly.
Best place to live, but the most expensive: Center City (north of South Street; east of the Schuylkill River; south of Fairmount Ave)
Next best place to live: University City (west of Schuylkill River; east of 45th street).
Check the following website for a map of Philadelphia:
http://map.mapnetwork.com/destination/philadelphia/
Good luck at Temple.