Dr. Robert Grunstein has always been a car and truck guy. So when he heard that an old municipal fire truck was up for sale ("the holy grail for car guys," he says), he bought it. The fire truck cost him $5,000; converting it into a mobile dental unit and taking out the water tank set him back $50,000. "It had a new motor and perfect transmission," Grunstein gushes. It’s the perfect vehicle, he says, for combating the "tsunami of bad teeth."