Figure 1.
Dentinal tubule occlusion of dentine discs after treatment.
(SEM, 5000×) (a, d) Dentinal tubules were empty without any occluding materials. (b, e) The majority of dentinal tubules were empty and a small number of dentinal tubules showed a sparse existence of occluding materials. The chunky occluding materials locate in the middle of the dentinal tubules with clear boundaries between the precipitate and dentin. (c, f) The majority of the dentinal tubules were blocked by materials. The occluding materials adhered to the dentinal wall with blurred boundaries between part of the precipitate and dentin.
Figure 2.
Dentinal tubule occlusion after mechanical brushing with distilled water.
(SEM, 5000×) (a, d) Dentinal tubules were empty with no occlusion. (b, e) Almost all dentinal tubules were empty with very few dentinal tubules showing little occluding materials. (c, f) Most of the dentinal tubules showed various levels of sediment blockage.
Figure 3.
Plugging rates of dentinal tubules.
The dentinal tubule plugging rate (n = 8) of the HA dentifrice group was significantly higher than that of the ordinary dentifrice group. *: P<0.01, compared with the ordinary dentifrice group.
Figure 4.
Atomic percentages of calcium and phosphorus in dentine discs.
The lines on top of the bars stand for standard deviation. *: P<0.01, the differences of the atomic percentage (n = 8) of Ca or P among groups were statistically significant. Based on mean rank, the order of the atomic percentages of Ca or P is: HA dentifrice group>ordinary dentifrice group>distilled water group.
Figure 5.
Concentration- and time-dependent removal rate of aqueous hexavalent chromium cations by dentifrices.
The aqueous hexavalent chromium cations removal rate of the HA dentifrice group is always higher than that of the ordinary dentifrice group.
Figure 6.
EDS spectra of dentifrice before and after sorption of chromium element.
There is chromium element in the precipitates from both ordinary and HA dentifrice after sorption.