Mercury from fillings contributes 3 to 4 times more mercury to our bodies than all the environmental sources combined. Many people still don't realize that the majority of the new cavities we see in children today occur just in the center of the molar teeth. The tiny groves there are flaws which invite early decay. By the age of 6 a child has 4 permanent first molars.
Mercury fillings require the removal of the middle third of the tooth.
The material itself is weak and cannot be used in a thin layer. The dentist must drill deeply into the softer dentin area of the tooth and drill undercuts into the healthy tooth even where there is no disease. This approach was developed in 1908 by G.V. Black. Mercury fillings also expand after being placed in the tooth. The bigger the filling the more they expand.