AsianScientist (Apr. 16, 2013) – Researchers in China have brought new meaning to the phrase ‘a pearly white smile’ by using pearls to repair damaged teeth.
Tooth enamel is made up of rod-like crystals of hydroxyapatite, a calcium phosphate mineral. It is the hardest tissue in the body, but is susceptible to erosion by food and bacterial acids. Methods of artificially rebuilding enamel often involve extreme temperature, pressure or pH conditions that make them impractical for clinical use.
Researchers from the Chinese Academy of Sciences and Fujian Medical University, both in Fuzhou, are working towards a more feasible solution using the natural composite, nacre (mother of pearl), from the inside of mollusc shells, to act as a template for the mineralization of tooth enamel.
Nacre is composed of layers of aragonite, a form of calcium carbonate, separated by an organic matrix of proteins and biopolymers called the Water Soluble Matrix (WSM). The WSM acts as a template for aragonite crystal growth during nacre formation, so the researchers thought it might also be able to influence the structure of hydroxyapatite crystals in enamel. They tested this using extracted human molars that had been deliberately damaged with a strong acid.
In the study, published in the journal CrystEngComm, the damaged teeth were immersed in a solution containing the isolated nacre WSM from mussel shells, along with calcium and phosphate ions, for three days.
X-ray diffraction (XRD) analysis and Fourier transformed infrared (FTIR) spectroscopy demonstrated that the new ‘enamel’ was also similar to the real thing in terms of smoothness and hardness.
Scanning electron microscope images revealed that the WSM-induced HAP nanorods were well bundled in parallel and densely arranged on the surface of the tooth. Without the WSM, the crystals that formed were randomly orientated. The ideal features, smoothness, and hardness of the WSM-induced HAP were further confirmed by the atomic force microscope (AFM) and digital Vicker’s Hardness tester.
The article can be found at: Li X et al. (2013) Facile In-vitro Hydroxyapatite Remineralization of Human Enamel with Remarkable Hardness.
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Source: RSC; Photo: Justin Mclean/Flickr/CC.
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