The University of Iowa’s College of Dentistry re-opens at 6:30 this morning with added security. It was closed yesterday while a police bomb squad searched the building after an e-mail bomb threat on Tuesday. Public Safety director Chuck Green says the college appears clean.Security is tighter now at the dental college. U-of-I spokeswoman Ann Rhodes says all doors wil be locked except for the main entrance and anyone entering the building will have to submit to being searched.Rhodes says aside from the added security, the University will try to operate as if everything is normal.While extra security will be guarding the doors, counselors will also be on hand to help and talk with anyone who has concerns.