[Determination of content and type of zinc binding in dentine after application of ZOE paste]

The article deals with the determination of zinc content in dentine after ZOE paste application as well as the investigation of the morphology ant morphological dentine changes caused by the paste action. The obtained data for the content of zinc in various dentine layers have shown that a marked zinc content elevation comparing to the natural content occurred only in the layers of which ZOE paste was directly applied. In anatomically deeper dentine layers (under ZOE paste), the content of zinc corresponded to the natural dentine level. On the basis of data obtained, it was concluded that during ZOE paste application no concomitant zinc diffusion occurred through the tooth tissue, but only zinc content was elevated in the dentine contact layer. However, on the basis of these data it was not possible to conclude weather chemical changes in the contact paste-dentine layer occurred or it made only a strong mechanical effect of paste on dentine adhesion. The investigation of dentine morphology which was removed by grinding (by mean used in dentistry practice) showed that this way of preparing the specimens caused the natural dentine structural alterations. By grinding dentine topography was completely affected. Very deep lesions and visible augmentation of the contact dentine surface that facilitated ZOE paste adhesion, occurred. Thus the permanent ZOE paste attachment to dentine occurred and dentine free energy decreased. In this way permanent adhesion of cement for dentine was impossible with negative consequences for the final therapy.