Abstract
The changes in the calcium and phosphorus contents of enamel which had been irradiated with a laser were studied by X-ray microanalysis and polarized light microscopy. Zonal changes were observed in the mineral concentration of the enamel. The changes were seen to take the form of a pressure-wave moving in the direction of the propagation of the laser beam. A similar zone formation was apparent in polarized light micrographs of the sections which were examined. A comparison was made between the results obtained by these two methods.