Issue 34, 2008 Journal of Materials Chemistry

Repair of enamel by using
hydroxyapatite nanoparticles as the building blocks

Li Li,^a 
Haihua
Pan,^a  Jinhui
Tao,^a  Xurong
Xu,^a  Caiyun
Mao,^b  Xinhua
Gu^b  and  Ruikang
Tang*^a 

The
application of calcium phosphates and their nanoparticles have been received
great attention. However, hydroxyapatite (HAP) is not suggested in dental
therapy to repair the damaged enamel directly although this compound has a
similar chemical composition to enamel. We note that the size-effects of HAP
are not taken into account in the previous studies as these artificial
particles frequently have sizes of hundreds of nanometres. It has recently been
revealed that the basic building blocks of enamel are 20-40 nm HAP
nanoparticles. We suggest that the repair effect of HAP can be greatly improved
if its dimensions can be reduced to the scale of the natural building blocks.
Compared with conventional HAP and nano amorphous calcium phosphate (ACP), our
in vitro experimental results demonstrate the advantages of 20 nm HAP in enamel
repairs. The results of scanning electron microscopy, confocal laser scanning
microscopy, quantitative measurement of the adsorption, dissolution kinetics,
and nanoindentation, show the strong affinity, excellent biocompatibility,
mechanical improvement, and the enhancement of erosion-free by using 20 nm
particles as the repairing agent. However, these excellent in vitro repair
effects cannot be observed when conventional HAP and ACP are applied.

​Clearly, nano HAP with a size of 20 nm shares similar characteristics to
the natural building blocks of enamel so that it may be used as an effective
repair material and anticaries agent. Our current study highlights the
analogues of nano building blocks of biominerals during biomedical
applications, which provide a novel pathway for biomimetic repair.

20nm크기의 나노 하이드록시아파타이트가 자연적인 에나멜의 블락형성의 특징과 유사하여 에나멜 리페어나 충치예방 물질로서 효과적이라는 것은 분명하다.