THE FORMATION OF EARLY CARIOUS LESIONS IN DENTAL ENAMEL

PART I

¹ Institute of Dental Research, United Dental Hospital, Sydney, Australia

1. Early lesions of enamel, some stained with methyl green and some with alizarin red S, were examined by incident and transmitted light.

2. Normal enamel remains uncolored by these dyes, but carious enamel stains quite readily.

3. The lesions appeared conoidal in longitudinal sections and rectangular in transverse sections, thus possessing a shape similar to that of a wedge.

4. The deepest parts of the lesions bear a relationship to the Hunter-Schreger lines; the striae of Retzius have a strong influence on the general shape of the lesion.

5. In the deepest parts of the lesions, segmentation of the individual prisms can be seen, and the earliest sign of the carious process appears to be limited to the substance between the prisms.

6. The sites in which organic structures are known to occur seem to be those most intimately linked with the carious processes. Decalcification of these areas seems likely to have occurred, but there is no indication as to whether the organic material has been affected or not.