Chinese scientists have found a new route to the perfect smile, using nanoparticles to repair tooth enamel.
Ruikang Tang at Zhejiang University and his team found that nanoparticles made from hydroxyapatite (HAP), a mineral which is the major component of dental enamel, adsorb very strongly onto the surface of the natural enamel - potentially enabling decayed teeth to be repaired and strengthened.
Dentists have found it hard to understand why synthetic hydroxyapatite has not been a good candidate for enamel repair, but they could now have the answer. |
Tang explains that up to now dentists have found it hard to understand why synthetic hydroxyapatite has not been a good candidate for enamel repair, but they could now have the answer.
In contrast to previous studies, Tang's group have used much smaller particles, which they say are similar to the size of the building blocks of dental enamel. The features of these 20 nm sized HAP nanoparticles may be more similar to the features of natural hydroxyapatite than those of the larger HAP particles that are usually used he explains.
George Nancollas, professor of oral biology at the University of Buffalo in the US, explains that the team's work with HAP nanoparticles has revealed some exciting possibilities for the remineralisation of decayed enamel. 'The apparent restoration of enamel hardness using an in vitro method is particularly significant. The challenge will be to control the kinetics of the process and to achieve a degree of reproducibility.'
In order to confirm the effects seen with the HAP nanoparticles in vitro, Tang says they need to extend their work to in vivo studies. 'We are also interested in using these nanoparticles to repair other apatite hard tissue like bone' he says.
Klaus Jandt, an expert in biomaterials research at Friedrich Schiller University of Jena in Germany, agrees. 'Enamel repair studies are important and of high relevance. In the future, it will be especially important to demonstrate the enamel repair potential in vivo and that the repaired enamel is mechanically stable'.
Repair of enamel by using hydroxyapatite nanoparticles as the building blocks
Li Li, Haihua Pan, Jinhui Tao, Xurong Xu, Caiyun Mao, Xinhua Gu and Ruikang Tang, J. Mater. Chem., 2008
DOI: 10.1039/b806090h
Article citation: Li Li, J. Mater. Chem., 2008, DOI: 10.1039/b806090h
Repair of enamel by using hydroxyapatite nanoparticles as the building blocks
Li Li, Haihua Pan, Jinhui Tao, Xurong Xu, Caiyun Mao, Xinhua Gu and Ruikang Tang
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.
