Calling all cars! Calling all cars! Be on the lookout for a Tulsa, Okla. dentist who fled in a rental car. He has been charged with producing child pornography and may still be armed with his Polaroid camera. \n The FBI has joined the search for Donald C. Johnson, 47, whose dental assistants uncovered a collection of 148 pictures showing young girls performing oral sex on him. The girls, apparently all patients, appeared to be as young as 4 and as old as 16. In the pictures, they are seated in the dental chair, a cloth draped over their eyes. \n It is believed the girls were sedated and anesthetized and perhaps not even conscious of what the dentist had placed in their mouths. Johnson was identified in the photos by his clothing and his wedding ring. \n Johnson has a wife and three daughters, ages 6, 13 and 16. He was on vacation with them in Estes Park, Colo. when he fled after learning of the investigation. His wife returned to Tulsa with their daughters this week and filed for divorce. \n Meanwhile, hundreds of Tulsa area parents have been calling the Tulsa County Victim Witness Center to learn if their daughters were among about 40 in the pictures taken from the office. Parents are being asked for details about their appointments on the theory that most of the pictures were taken on afternoons when Johnson worked alone. \n The FBI is calling Johnson a fugitive and has issued a watch for him to the U.S. Border Patrol. And, yes, the Oklahoma state dental board has suspended Johnson's license.