In general, stainless steel crowns are used for children's teeth because they don't require multiple dental visits to put in place and so are more cost- effective than custom-made crowns and prophylactic dental care needed to protect a tooth without a crown.
Phosphorus comes from many places. You might think that the biggest sources of phosphorus are the obvious onesâsewage treatment plants, chemical factories, and the like. But in fact, identifiable sources such as these contribute less than 20% of the phosphorus in the river.
Quick Answer. Aluminum comes from several sources; it rarely occurs in pure form in nature, and is most frequently found embedded in other minerals, primarily bauxite. Bauxite and aluminum bear many physical characteristics; bauxite is comprised primarily of aluminum oxides, but has a slightly different shape and color.