STUDIES OF THE COMPOSITION OF TEETH

V. VARIATIONS IN THE AMINO ACID COMPOSITION OF DENTIN AND ENAMEL

¹ Department of Dental Research, Army Medical Service Graduate School, Walter Reed Army Medical Center, Washington, D. C.

A comparison has been made of the influence of various factors upon the amino acid composition of human enamel and dentin. Dentinal protein was affected by preservation and storage of teeth while enamel protein was not changed by such treatment. Flotation procedures did not alter the amino acid composition of dentin, but changes were noted in the amino acid composition of enamel. Therefore, separation by chipping is a more satisfactory way of separating enamel. Decalcification by acids and in the neutral sodium salt of ethylene diamine tetraacetic acid (EDTA) causes some solubilization of nitrogenous components of dentin but EDTA decalcification causes the least change in the organic matrix of this tissue. The amino acid composition of dentin cannot be considered to be definite until the nitrogenous fraction rendered soluble during decalcification is accounted for. The same may be true for enamel protein.