氟是最活泼的非金属元素。氟化钠是可溶性氟化物,有剧毒。皮肤接触氟化钠会造成严重灼伤。氟又是人体必需的元素。自然环境中缺乏氟的地区,儿童中往往流行龋齿病,氟化物有一定的防龋效果。因为氟是以氟化钙和氟磷灰石存在于牙齿组织中,它们都是难溶物质,有抗酸作用。同时唾液中含氟化物可以抑制乳酸杆菌的生长,减少乳酸杆 Fluorine is the most active non-metallic element. Sodium fluoride is a soluble fluoride, highly toxic. Skin contact with sodium fluoride can cause severe burns. Fluorine is an essential element of the human body. In areas where there is a lack of fluoride in the natural environment, there is a prevalence of dental caries in children, and fluoride has a definite caries-preventive effect. Because fluoride is present in dental tissues as calcium fluoride and fluorapatite, they are both insoluble and have an antacid effect. At the same time fluoride in saliva can inhibit the growth of lactobacilli, reduce the lactic acid lever