IADR Abstract Archives
THE DIFFUSION OF CADMIUM AND STRONTIUM SALTS IN HUMAN DENTAL ENAMEL
Objectives: To study the cadmium chloride and strontium bromide diffusion in human sound (SDE) and artificially induced demineralized dental enamel (IDE) determined by electron scanning microscopy-energy dispersive X-ray analysis (SEM-EDX) taking into account the ionic radii, ion polarity and net charge.
Methods: Sixty human sound third molars were collected and randomly divided into two groups (n=30): G1 sound enamel (SDE) and G2 dental enamel with induced demineralization (IDE). Demineralization was induced by an abridged method using racemic lactic acid at pH=5.4. The diffusing ions were provided by aqueous solutions containing Cl-, Cd++, Sr++ and Br- at two concentrations (low=C1, high=C2), exposure was done at three times(t1=4, t2= 8 and t3= 16 days), at 36.5 °C. The SEM-EDX results for area percent atomic content (APAC) for each ion was determined at three depths (50, 100 and 150 micrometers) in both types of enamel. The statistical analysis used repeated measurements fitting a beta regression model with software R versión 3.0.2.
Results: The APAC was larger with C2 than C1. The APAC was higher in IDE than in SDE, as expected. Among ions, mass transport is larger for Cd++ and Cl- due to the fact that these two possess the smaller ionic radii for the two cations or the two anions. Time of exposure to C1 and C2 as well as depth were statistically non-significant.
Conclusions: Mass transport through enamel depends on mineralization degree, solution concentration and ionic radii of chemical species. Mass transport seems to depend on a complex mechanism and it proceeds faster than expected for pure diffusion.
Methods: Sixty human sound third molars were collected and randomly divided into two groups (n=30): G1 sound enamel (SDE) and G2 dental enamel with induced demineralization (IDE). Demineralization was induced by an abridged method using racemic lactic acid at pH=5.4. The diffusing ions were provided by aqueous solutions containing Cl-, Cd++, Sr++ and Br- at two concentrations (low=C1, high=C2), exposure was done at three times(t1=4, t2= 8 and t3= 16 days), at 36.5 °C. The SEM-EDX results for area percent atomic content (APAC) for each ion was determined at three depths (50, 100 and 150 micrometers) in both types of enamel. The statistical analysis used repeated measurements fitting a beta regression model with software R versión 3.0.2.
Results: The APAC was larger with C2 than C1. The APAC was higher in IDE than in SDE, as expected. Among ions, mass transport is larger for Cd++ and Cl- due to the fact that these two possess the smaller ionic radii for the two cations or the two anions. Time of exposure to C1 and C2 as well as depth were statistically non-significant.
Conclusions: Mass transport through enamel depends on mineralization degree, solution concentration and ionic radii of chemical species. Mass transport seems to depend on a complex mechanism and it proceeds faster than expected for pure diffusion.