Dental amalgam controversy demonstrated that mercury released from amalgam restorations does not give rise to toxic effects on the nervous system of children. More recently, a Cochrane Systematic review in 2014 found, "insufficient evidence to support or refute any adverse effects associated with amalgam or composite restorations." Those opposed to dental amalgam suggest that mercury from dental amalgam may lead to nephrotoxicity, neurobehavioural changes, autoimmunity, oxidative stress, autism, skin and mucosa alterations, non-specific symptoms and complaints, Alzheimer's disease, and multiple sclerosis. Both those opposed and those not opposed to dental amalgam recognize that amalgam has been found to be a rare contributor to
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