CHEMICAL AND PHYSICAL STUDIES OF ENAMEL FROM HUMAN TEETH

I. SPECIFIC GRAVITY AND NITROGEN CONTENT OF ENAMEL FROM DIFFERENT SURFACES

¹ Department of Anatomy and Division of Dental Research, University of Rochester School of Medicine and Dentistry, Rochester, N. Y.

1. Density and nitrogen determinations on enamel samples obtained from tooth slices by using an Airdent machine were carried out by Melon's micropyenometric technic and a semimicro-Kjeldahl procedure, respectively.

2. Density and nitrogen determinations on 286 samples from sound teeth suggested that enamel from the buccolingual surfaces (155 samples) had a higher density and lower nitrogen content than enamel from the mesiodistal surfaces (131 samples) of teeth from similar age groups.

3. Sound enamel from noncarious teeth had a higher nitrogen content than sound enamel from carious teeth; these differences were reflected in the mesiodistal surfaces of the noncarious teeth. Marked density differences were not observed.