The Number of Prism Bases on the Inner and Outer Surface of the Enamel Mantle of Human Teeth

¹ Institute of Anatomy, University of Bergen, Bergen, Norway

The statistical determination of the total number of prism bases on the inner and outer surface of the enamel mantle of two human teeth was attempted.

Using the serial planoparallel surface grinding technique, the enamel mantles were reproduced in enlarged wax models. This was done to measure the inner and outer surfaces of the enamel mantles. From the wax models were made foil replicas of the surfaces. These in turn were cut up in small triangles, which were measured separately.

The ground surfaces of the teeth were examined under the microscope. By counting, a mean number of prism rods per length unit along the outer and inner borders of the enamel mantle in each separate ground plane was found. From these mean numbers from a series of ground planes the mean number of prism bases per surface unit on the outer surface of the enamel mantle and the number per surface unit on the inner surface were calculated. Having found the sizes of the surfaces from the wax models, the total numbers of prism bases on the surfaces were calculated.

It was found from the investigation of the first tooth that the total number of prism bases on the inner surface of the enamel mantle exceeded the number on the outer surface by 10.6 per cent. From the investigation of the second tooth it was found that the number on the inner surface exceeded the number on the outer by 7.8 per cent.