PERMEABLE STRUCTURES IN NORMAL ENAMEL

¹ Department of Histology, University of Utrecht, Utrecht, Netherlands

Much of the confusion in literature concerning the permeability of enamel must be ascribed to the failure of many authors in observing the limitations of the methods they used.

First of all, therefore, we tried to divide the problem of permeability in several parts and we discussed the technical difficulties encountered if one tries to cover the problem in its entirety.

Next, the possibilities, and the limitations, of an investigation with dyes applied on unimpaired enamel were given.

The reason why Trypaflavin, a fluorescent dye, was chosen and the measures taken in order to prevent dislocation of the dye during the preparation of the specimens were discussed in detail.

The results were that Trypaflavin permeated unimpaired enamel of dogs' deciduous (and, to a somewhat lesser extent, permanent) teeth. It was found in the prism sheaths, the tufts, and the lamellae.

After an application of 2 minutes' duration of a 1/2 per cent Trypaflavin solution the dye was found to have permeated the whole depth of the enamel cap of a dog's deciduous canine.

It was stressed that, although this investigation did not yield new morphological data, it certainly proved for the first time that the above-mentioned structures of the enamel really can act as channels of permeability under normal circumstances.

Finally, some problems arising from but not solved by this investigation were discussed.