It happened at the office of Dr. Gregory Wasko at 7:45 a.m. Thursday in the 5200 block of Castor Avenue.
According to investigators, when a receptionist arrived to open the office, a man followed her inside and asked if they accepted the Keystone health plan.
"He posed as a patient as she came in for the morning. He did say he was going to attack her. That's when she screamed and he left," said Dr. Wasko.
He then tried to sexually assault the woman. Police say she fought off her attacker.
Dr. Gregory Wasko has owned and operated his dentistry at Castor and Pratt for 25 years. "Fortunately, she was not assaulted. Her screams drove the person off," Dr. Wasko said. He calls the attack a first for the busy neighborhood. "It's a new experience for us and hopefully the last," Dr. Wasko said. Detectives from the Special Victims Unit are investigating.
The suspect is described as a black man betwen 30 and 35 years old.
He stands about six feet tall with a medium build.
He was wearing a dark colored baseball cap, a dark colored hooded sweatshirt, and a waist-length old style green and silver Philadelphia Eagles jacket.
Anyone with information is asked to call police at 215-685-3251.