The Fractionation of Human Tooth Enamel on the Basis of Density

¹ Chemistry Department, Northwestern University Dental School, Chicago, Illinois

Human tooth enamel was finely divided by forcibly ejecting it against a silicon carbide crystal. The finely powdered enamel was then separated on the basis of density and analyzed for organic material, calcium, phosphorus, carbon dioxide, magnesium, sodium, and potassium. The more dense fraction of enamel contained 0.27 per cent organic material, while the light contained 2.3 per cent organic material. As the fractions became more dense, the calcium, phosphorus, carbon dioxide, magnesium, sodium, and potassium increased. The lighter fraction contained a lesser concentration of these inorganic ions. It is thought that the heavier fraction came primarily from the enamel rods, while the lighter fraction came from the interprismatic substance.