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[Nano-scratch research of amelogenesis imperfecta teeth].

OBJECTIVE
To study the differences between amelogenesis imperfecta (AI) teeth and normal human (NH) teeth in wear properties.


METHODS
The ultrastructure of the human tooth enamel from adult patient diagnosed with AI was investigated using atomic force microscope (AFM) and compared with the surface of normal human tooth enamel. The composition of tooth enamel of AI teeth and normal human teeth were analyzed by energydispersive X-ray spectroscopy (EDX). The properties of micro-friction and wear between AI teeth and normal human teeth were compared using nano-scratch technology and scanning electron microscope (SEM).


RESULTS
The AI teeth were found porosity and the loosely packed hydroxyapatite was distributed randomly compared with normal human teeth. The amount of C was higher while the amount of Ca, P were lower in AI teeth than normal human teeth. The friction coefficient of both AI teeth and normal human teeth was increasing with the load increased and the friction coefficient of AI teeth was higher than normal human teeth with the same load. Meanwhile, the destruction of AI teeth was more severe than normal human teeth with the same load.


CONCLUSION
The AI teeth has significant differences with normal human teeth on micro-structure, composition and micro-friction and wear properties. Thus, we need to have a general consideration of all these results when doing clinical restorations.