Dentistry dates back to when humans first had teeth...well, not quite that far back. One research, however, discovered evidence of teeth drilling in skulls dating from 7,500 to 9,000 years ago. A prehistoric bow drill was most likely used to make the holes. Could that be the first dentist's work? According to the BBC, "one rotting tooth in the jaw had been carefully scrubbed and scraped with a tool" according to a study undertaken by the University of Bologna, Italy on a 14,000-year-old skull. That makes dentistry one of the oldest documented professions, which is certainly caused for celebration.