Volume 55 (2005) Issue: 2005 No#1

Extent of diffusion of organic molecules in the enamel tissue of dogs

Author(s): Tihaček-Šojić Ljiljana

Keywords:diffusion, enamel tissue, diffusion coefficient, EPR

The objective of this study was to evalute the extent of diffusion of organic molecules in the enamel tissue, of permanent teeth. The experimental study was performed in vivo on dogs. To the experomental dogs the molars on the right side of the lower jaw underwent enamel tissue reduction without additionaly placing any tooth protection. Teeth on the left side of the lower jaw were left intact thus rapresenting the control. After 12 months animals were sacrificed,experimental and control teeth extracted and the study of diffusion in vitro carried on. For that purpose an organic spin marker 4-amino – 2,2,6,6,-tetramethylpiperdinyl 1-oxi (4-Amino-Tempo) was selected. The property of this marker is that it contains a nitroxide radical which is stable in a neutral and base enviroment, and due to the unbound spin of the free radical it is higly siutable for the electronic paramagnetic resonance method (EPR). Studies on the diffusion of organic spin markers in the enamel tissue are performed by submerging the prepared tooth in a water solution containing the marker substance. From the intensity of the EPR spectrum filmed after tooth withdrawal from the water solution, distribution, diffusion time and penetration depth of marker molecules were established. Coefficients of organic spin marker diffusion and saturation concentrations of marker molecules in the enamel were determined.The observed variations in the areal and time for disribution of diffused molecules were explained by the binding possibility of the NO –radical from the marker molecule to the enamel tissue.The results of the experiment contained in this work contribute to a better understanding of the spin marker organic molecule movement through the enamel tissue which is controlled by the mechanism of diffusion and chemical bonding of the marker molecule to the enamel structure. The results of the experimental research also indicate the harmful effects of leaving the enamel tissue without protection.