NIUMAG
Fluorine Content in Fluoride Toothpaste Tested by Low-Field NMR
Fluoride Toothpaste
Fluoride toothpaste refers to toothpaste that contains fluoride. Scientists have found that fluoride can effectively prevent dental caries and enhance the ability of teeth to resist caries. For children, especially children under 6 years old, due to poor swallowing reflex, attention should be paid to prevent excessive fluoride intake.
Fluorine Content Effects Fluoride Toothpaste
1. Directly inhibit the bacteria of dental plaque: Fluorine has an inhibitory effect on acid-producing bacteria. It can inhibit the storage of intracellular polysaccharide of Streptococcus cariogenicum, affecting the growth and reproduction of bacteria; inhibit the synthesis of extracellular polysaccharide by Streptococcus cariogenicum, and reduce the adhesion of bacteria and plaque on the tooth surface.
2. The effect of fluoride on tooth enamel: The dental pellicle is the basis for bacteria to attach to the tooth surface, and fluorine plays an important role in inhibiting the formation of dental pellicle and the growth of plaque. The exchange of fluoride ions with hydroxide ions in enamel hydroxyapatite to form fluorapatite will enhance the structure of enamel, reduce solubility, and enhance anti-caries ability.
3. Promotes mineralization: Promotes remineralization of enamel that has been demineralized at the beginning of caries.
Fluorine Content Tested by Niumag NMR
Fluorine content can be measured quickly and accurately using low-field NMR, independent of fluoride compounds and toothpaste formulations. The method is fast, easy to operate and calibrate, and requires no additional sample preparation and can be used without training. The speed and simplicity of NMR makes it the leading method for fluorine content testing in manufacturing, product development and quality control.
Fluorine Content Measurement by NMR
The NMR method is based on the linear relationship between the content of fluorine nuclei in the sample and the intensity of the NMR signal. The NMR signal amplitude is proportional to the mass of soluble fluorine, and through this linear relationship, the fluorine content of the sample to be tested can be quickly detected.
Since solid or insoluble fluorine signals decay very quickly, such as in calcium fluoride (CaF2) or magnesium fluoride (MgF2), only soluble fluorine is detected in the NMR signal. The measurement was performed using a spin echo sequence. Figure 1 shows the spin echo sequence and the detected NMR signal. The free induction decay (FID) NMR signal was measured at t1 after the 90-degree RF pulse. At this point the signal intensity (A1) is the sum of the soluble and insoluble fluorine signals in the sample. After the 180-degree pulse, the amplitude of the detected spin echo signal is A2. At this time, the signal of insoluble fluorine has been attenuated to 0, and A2 is only the signal intensity of soluble fluorine. Therefore, the signal intensity A2 is proportional to the fluorine content of the sample.
