A lawsuit filed this week accuses the American Dental Association of misleading the public about alleged dangers in tooth fillings, but an Iowa dental expert say there’s no problem.The suit alleges mercury in silver amalgam can poison the body and may be linked to a variety of ailments, including Alzheimer’s Disease. Bob Harpster, executive director of the Iowa Dental Association, says when mercury is combined with other metals in amalgam fillings, it forms a very hard, stable and -safe- material.Harpster says having a dentist remove one’s silver fillings could be risky. He says more damage could be done to healthy teeth as a doctor tries to remove the filling.Harpster says the silver amalgam fillings are the material of choice for a majority of Iowa dentists.