Dental amalgam controversy (unlike composites), and is often about 20-30% less expensive. "Consumer Reports" has suggested that many who claim dental amalgam is not safe are "prospecting for disease" and using pseudoscience to scare patients into more lucrative treatment options. Those opposed to amalgam use suggest that modern composites are improving in strength. In addition to their claims of possible health and ethical issues, opponents of dental amalgam fillings claim amalgam fillings contribute to mercury contamination of the environment. The World Health Organization (WHO) reports that health care facilities, including dental offices, account for as much as 5% of total waste water mercury
Real element formula_1, Every involution is strongly real. Furthermore, every element that is the product of two involutions is strongly real. Conversely, every strongly real element is the product of two involutions. If and formula_1 is real in formula_2 and formula_30 is odd, then formula_1 is strongly real in formula_2. The extended centralizer of an element formula_1 of a group formula_2 is defined as making the extended centralizer of an element formula_1 equal to the normalizer of the set The extended centralizer of an element of a group formula_2 is always a subgroup of formula_2. For involutions or non-real elements, centralizer and