Crystallinity refers to the degree of structural order in a solid and has a big influence on hardness, density, transparency and diffusion. Even within materials that are crystalline completely, the degree of structur...Crystallinity refers to the degree of structural order in a solid and has a big influence on hardness, density, transparency and diffusion. Even within materials that are crystalline completely, the degree of structural perfection can vary, reflecting size and elastic strain of many independent crystalline regions (grains or crystallites) of which these materials are composed. In this work it was attempted to reduce the crystallinity of human enamel using a technique of mechanical grinding (MG) with an ultra-compact FRITSCH Mini-Mill PULVERISETTE 23 machine. Variation in the crystallinity through the MG was monitored by X-ray diffraction (XRD) by broadening of the diffraction peak and examined using the Williamson-Hall plot method. Crystallites in human enamel are regularly arranged and oriented (in the [001] direction) perpendicularly to the interface of enameldentin junction. The results showed an anisotropic feature in crystallinity. Reduction of the crystallinity along the a-axis is due to the crystal strain rather than to the refinement of crystal, and vice versa along the c-axis. After 230 h of the MG, the length of crystallites decreased from 100 nm to 30 nm and width from 40 nm to 37 nm approximately.展开更多
In this in vitro study,the restoration of acid-eroded enamel surface morphology and anti-wear properties under two conditions,mono-remineralization(treated with remineralization alone)and impact-remineralization(treat...In this in vitro study,the restoration of acid-eroded enamel surface morphology and anti-wear properties under two conditions,mono-remineralization(treated with remineralization alone)and impact-remineralization(treated with cyclic impact followed by remineralization),are characterized to determine the effect of occlusal loading on enamel remineralization.Compared with the mono-remineralized surface,the impact-remineralized surface demonstrates better anti-wear performance,as manifested by a higher hardness and elastic modulus,as well as a lower friction coefficient and wear volume.Loading on the eroded enamel surface induces the fragmentation of hydroxyapatite nanoparticles,which aids crystal deposition and fusion during subsequent remineralization.In summary,owing to the enamel microstructure,occlusal loading can promote the restoration of enamel anti-wear properties by enhancing remineralization.Remineralization enhancement through occlusalloading-induced nanoparticle fragmentation plays a significant role in preventing human teeth from excessive wear.展开更多
文摘Crystallinity refers to the degree of structural order in a solid and has a big influence on hardness, density, transparency and diffusion. Even within materials that are crystalline completely, the degree of structural perfection can vary, reflecting size and elastic strain of many independent crystalline regions (grains or crystallites) of which these materials are composed. In this work it was attempted to reduce the crystallinity of human enamel using a technique of mechanical grinding (MG) with an ultra-compact FRITSCH Mini-Mill PULVERISETTE 23 machine. Variation in the crystallinity through the MG was monitored by X-ray diffraction (XRD) by broadening of the diffraction peak and examined using the Williamson-Hall plot method. Crystallites in human enamel are regularly arranged and oriented (in the [001] direction) perpendicularly to the interface of enameldentin junction. The results showed an anisotropic feature in crystallinity. Reduction of the crystallinity along the a-axis is due to the crystal strain rather than to the refinement of crystal, and vice versa along the c-axis. After 230 h of the MG, the length of crystallites decreased from 100 nm to 30 nm and width from 40 nm to 37 nm approximately.
基金This work was supported by the National Natural Science Foundation of China(Nos.52035001,51675449,and 51535010)the 111 Project of China(No.B20008).
文摘In this in vitro study,the restoration of acid-eroded enamel surface morphology and anti-wear properties under two conditions,mono-remineralization(treated with remineralization alone)and impact-remineralization(treated with cyclic impact followed by remineralization),are characterized to determine the effect of occlusal loading on enamel remineralization.Compared with the mono-remineralized surface,the impact-remineralized surface demonstrates better anti-wear performance,as manifested by a higher hardness and elastic modulus,as well as a lower friction coefficient and wear volume.Loading on the eroded enamel surface induces the fragmentation of hydroxyapatite nanoparticles,which aids crystal deposition and fusion during subsequent remineralization.In summary,owing to the enamel microstructure,occlusal loading can promote the restoration of enamel anti-wear properties by enhancing remineralization.Remineralization enhancement through occlusalloading-induced nanoparticle fragmentation plays a significant role in preventing human teeth from excessive wear.
