Amalgam (dentistry) can cross the placenta leading to stillbirths and birth defects. A combination of mercury and non-ionizing radiation has been suggested as a factor in the recent increase in reported autism spectrum disorders. It has been reported that there is a positive correlation between the maternal and cord blood mercury levels. Although there is no evidence linking amalgam use and pregnancy damage, it is advisable to delay or avoid dealing with amalgam fillings in pregnant patients. Dentists are urged by some to consider the selection of restorative material more seriously and avoid using amalgam when possible. The dental operating team should
Chemical element whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than 1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of a "pure element". In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the