Biomaterials Science and uses
Some literatures disclosed that the dental plaque pH after a sucrose rinse can decrease to 4.5 or even. A pH of higher than 6 is considered to be the safe area, a plaque pH of 6.0~5.5 is the potentially cariogenic area, and pH of 5.5~4 is the cariogenic or dangerous area for cavity formation. Therefore, the maintenance of a higher pH value in the plaque is very important for the antiquaries. The fluoride has been used for about five decades in caries prevention. However, it is difficult to control its quantity to a proper level excessive fluoride is harmful to human body and insufficient fluoride will not take effect for antiquary’s action. In recent years much attention has been paid to developing fluoride-free techniques that can prevent human teeth from caries. Some natural products were reported to be candidates of new ant cariogenic substances. However, there is no scientific evidence about the effect of natural tourmaline on the streptococcus mutants. Tourmaline is a kind of electro polar mineral belonging to the original space group of R3m, whose general chemical formula.
Its Crystal structure of tourmaline. The most important feature among the electric properties of the tourmaline is the possession of spontaneous and permanent poles, which would produce an electric dipole, especially in a small powder with a diameter of several microns or less. Therefore, a strong electric field exists on the surface of a tourmaline powder. The electric field effect of tourmaline powders can influence the redox potential of water and regulated the pH value of solution. The maintenance of pH value is very important for the growth and metabolism of bacteria. Therefore, the graded composite materials were fabricated with nano-tourmaline and nano-hydroxyapatite powders by direct inkjet color printing for the study of inhibiting function on streptococcus mutants. Moreover, the mechanism by which tourmaline inhibits the growth and acid production of streptococcus mutants was also explained from the view of pH value.
Tourmaline powders were from the Inner Mongolia Autonomous Region of China, whose chemical compositions were analyzed by EDAX Phoenix energy dispersion spectroscope (EDS) and given in the mass ratio as follows The preparation of nanohydroxyapatite powders was reported. The streptococcus mutants were purchased from Tianjin Medical University, China. Brain heart infusion (BHI) broth, mitis salivarius agar (MSA) and phenol red broth were purchased from Hangzhou Tianhe Microorganism Reagent Co., Ltd., China. Other reagents were analytical. These tourmaline and hydroxyapatite inks with ethyl alcohol as the carrier and oleic acid as the dispersant had a solid loading of 15 and 20 wt%, respectively. After mixing the powders in ethyl alcohol, the suspensions were kept in the ultrasonicator for 1 h. Then, sedimentation experiments for more than 24 h confirmed that this was indeed the case. To provide the visual appreciation of the graded materials fabricated, the tourmaline suspension was mixed with 20 wt% of the commercial XaarJet magenta ink, whereas the hydroxyapatite suspension was mixed with 20 wt% of the XaarJet cyan ink. The streptococcus mutans can be cultured on the graded materials.
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Journal of Biochemistry & Biotechnology