Biomedical Engineering Reference
In-Depth Information
5.7
Summary
We performed scratching tests on the longitudinally sectioned enamel surface along
the directions vertical and parallel to the enamel rods, respectively. We also investi-
gated the recovery of the scratched enamel in remineralization. Based on the given
test conditions, the main conclusions can be summarized as follows:
1. The nanomechanical properties of the enamel rod were better than those of the
interrod enamel, and they were heterogeneous over its occlusal cross section. For
a single enamel rod, the hardness and Young's modulus were higher in the cen-
tral head area and tended to be lower in the edge area, especially in the tail area.
2. The scratch-induced damage was anisotropic on the longitudinal section of tooth
enamel. Aside from the unique alignment of HA crystallites, the buffer capacity
of the interrod enamel led to a good wear resistance of tooth enamel when
scratched along the direction parallel to the axis of the enamel rod.
3. Because of its lower hardness, the interrod enamel revealed a relatively weaker
wear resistance than the enamel rods even though the buffer capacity of the inter-
rod enamel played an important role during the masticating process of human
teeth.
4. The enamel HA crystals were found to be broken up into smaller ones by scratch-
ing. Since such behavior may be helpful to release the stress concentration and
prevent the generation of cracks in teeth during the masticating process, it can
effectively improve the wear property of teeth.
5. After tooth samples were remineralized in artificial saliva, we found that the size
of particles on the surface increased to 200 nm and the damaged tooth enamel
surface could be repaired to some extent.
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