Dentists keep dying of this deadly lung disease. The CDC can't figure out why.

Seven of the patients were dead, and two more were dying of a rare chronic, progressive lung disease that can be treated but not cured.It's estimated that about 200,000 people in the United States have Idiopathic Pulmonary Fibrosis (IPF) at any one time.But the common denominator of a small group of patients at a Virginia clinic over a 15-year period is worrying the Centers for Disease Control: Eight were dentists; a ninth was a dental technician.The dental professionals were 23 times more likel