The Food and Drug Administration has ordered a review of the performance of artificial jaw joint implants after finding a substantial number of problems with the products in recent years. The action comes a couple months after a Journal Sentinel investigation found that the agency had approved four such devices beginning in 1999, despite weak and incomplete research clouded by potential conflicts of interest. In announcing the action, the agency said it found a substantial number of adverse events involving the devices between 2004 and 2010, including patients who had to have devices removed prematurely after they were implanted because of extreme pain. Many of those patients were forced to undergo surgery to remove the devices in less than three years. That is considerably shorter than the expected five-year minimum, the agency said.