2007 Volume 50 Issue 3 Pages 302-312
A number of studies have suggested that green tea has antibacterial and anticariogenic properties, with such properties generally having been attributed to the inherent catechin and fluoride present within tea leaves, both in vitro and in vivo. The aim of this experiment was to determine the effect of fluoride, derived from partially refined green tea extract (PF-4; fluoride concentration was 3,900μg/g), on the demineralization of enamel and dentin in vitro and further, to discuss its efficacy as a means of caries prevention. Demineralizing acid buffers containing 0.01, 0.05, 0.1, 0.2, 0.4, and 0.8 weight percent of PF-4, and 0.4 ppm F and 4.0 ppm F as NaF, were prepared. Finely polished bovine enamel and dentin blocks with windows were immersed in these demineralizing buffers for four days at 37℃. The mineral profiles, integrated mineral loss(IML) and lesion depth(Ld) were analyzed by transversal microradiography(TMR). Lesion formations on the enamel and dentin of the buffers containing low concentrations of PF-4 were characterized by a surface layer of relatively thick but low mineral volume and a less demineralized body of lesions, when compared with the lesions formed by the same amounts of the buffers containing fluoride (NaF). The IML of both enamel and dentin showed a gradual preventive effect against demineralization as PF-4 concentration increased. Enamel lesions formed with the PF-4 buffer showed a decrease in IML and Ld, while dentin showed decreased IML, but unchanged Ld with a commensurate increase in PF-4 concentration. These findings typify the demineralizing traits of buffers containing PF-4 and are thought to be caused by the development of diffusion barriers, which were formed by tea-derived organic substrates and amino acids, and aluminum and several metallic ions binding to the apatitic surface of tooth substrates. In conclusion, this in vitro study demonstrated that the anti-demineralizing effect of PF-4 is most likely characterized by decreasing demineralization of the body of lesions. It also suggested that low concentrations of PF-4 appear to nlav a more effective role in this than NaF.
