Dental amalgam controversy an increasing number of studies with larger sample sizes are being conducted. Those who are not opposed to amalgam claim that, aside from rare and localized tissue irritation, recent evidence-based research has continued to demonstrate no ill effects from the minute amounts of mercury exposure from amalgam fillings. A 2004 systematic review conducted by the Life Sciences Research Office, whose clients include the FDA and NIH, concluded that, "the current data are insufficient to support an association between mercury release from dental amalgam and the various complaints that have been attributed to this restoration material." A systematic review in 2009
Dental amalgam controversy expansion and contraction of the various amalgam products. During the American Civil War, the debate on the merits of amalgam continued. In dental meetings, with now decades of use and dental research came the recognition of the importance of good technique and proper mixture on long-term success. It was argued that, "the fault was not in the material but in the manipulation...Some men's amalgam is good universally, and some men's gold is bad universally; the difference lies in the preparation of the tooth and in the plug (filling)." More controversy came in 1872, when an amalgam filling was reported as