从公共卫生的角度探讨含氟牙膏引起氟中毒的危险性。

选用3周龄清洁型SD大鼠42只，按雌雄各半体重均衡原则随机分为7组（A组，阴性对照组；B组，阳性对照组；C组，50%含氟牙膏浓度灌胃组；D组，100%含氟牙膏浓度灌胃组；E组，30 mg/L NaF溶液组；F组，30 mg/L NaF溶液组+50%含氟牙膏浓度灌胃组；G组，30 mg/L NaF溶液组+100%含氟牙膏浓度灌胃组），每组6只。实验每周记录大鼠一般情况、体重；第0和112天分别测量采集尿液及血清，检测标本氟含量并记录分析；第0、28、56、84和112天分别记录各组下颌中切牙氟斑牙发生情况，根据氟斑牙分级计分统计。在第112天麻醉下处死各组大鼠，留取下颌中切牙，经苏木精-伊红染色切片观察牙齿结构改变。

（1）大鼠体内尿氟和血氟含量会随着氟摄入量增高会有不断上升趋势，但当进入高氟摄入量时，上升幅度变缓，有1个平台期。（2）大鼠下切牙氟斑牙变化情况：在第28天，B组下切牙釉质表面可见棕白相间的细横纹，横纹逐渐向切方不断生长，但未发现釉质明显实质性缺损；第56天时，G组可见棕白相间横纹，釉质透明度下降，B组见少许白垩色斑块出现；第84天时，B组及G组个别大鼠出现粉笔样颜色改变，釉质透明度浑浊，E、F组个别大鼠出现棕白相间横纹，A、C呈棕色或棕黄色，表面光滑，半透明状，D组有1只大鼠釉质半透明改变，少许混浊；第112天时，B组及G组大鼠出现粉笔样颜色改变，釉质透明度浑浊，E、F组大鼠出现棕白相间横纹，横纹间见0.5~ 1 mm宽的透明区，A、C、D组与第84天的情况无明显差异。（3）大鼠下切牙病理切片情况：B、F、G组与A组比较，生长线均有明显的加深、加重，结构排列不均一。E组与A组比较，生长线有加深、加重，结构排列不均，但无B、F、G组明显；C、D组与A组比较，生长线及结构排列没有明显异常。

高氟地区学龄前儿童使用含氟牙膏，可能会促进氟斑牙的产生；适氟地区的学龄前儿童使用含氟牙膏，须掌握使用方法，否则可能与儿童在其他日常生活中摄入的氟一起导致体内氟含量超标，促进氟斑牙的产生。

To test the safety of the use of fluoride toothpaste and the establishment of fluoride toothpaste type dental fluorosis animal model on the basis of public health on the point of view of fluoride toothpaste discussed by fluorosis risk.

Choose 3 weeks clean type 42 only SD rats, according to male and female half weight equilibrium principle randomly divided into seven groups with six rats each. Grouping was as follows: group A: negative control; group B: positive control; group C: 50% fluoride toothpaste concentration irrigation stomach group; group D: 100% fluoride toothpaste concentration irrigation stomach group; group E: 30 mg/L NaF solution group; group F: 30 mg/L NaF solution group + 50% fluoride toothpaste concentration irrigation stomach group; group G: 30 mg/L NaF solution group + 100% fluoride toothpaste concentration irrigation stomach group. The general situation and weight of the experimental rats were recorded every week. The urine and serum were collected at 0 day and 112 days. The specimen fluorine content and record analysis were investigated. The mandibular incisor of dental fluorosis conditions were recorded at 0 day, 28 days, 56 days, 84 days and 112 days respectively and according to the dental fluorosis grading scoring statistics. Harvested the rats at the 112th day under anesthesia. Mandible incisors of each rat were stained with the hematoxylin-eosin (HE) to observe the change of teeth structure.

(1) The concentration of fluorine in rats urine as well as blood fluorine concentration were increased continually as fluorine intake increased. The blood fluorine concentration in rats reached a stationary platform phase when high concentration fluorine was provided. (2) The rats dental fluorosis teeth had various changes as follows: in 28 days, group B enamel surface had visible brown and white horizontal grain from gingival region to incisal margin but did not identify any enamel substantial defect; in 56 days, group G visible brown and white horizontal grain appeared and the reduced transparency in enamel could be seen as well as group B showed a little cretaceous splash piece in the enamel; in 84 days, some of the rats in group B and group G rats appeared chalk like color changes and enamel transparency turbidity. Some of the rats in group E, F showed brown and white horizontal grain in the enamel. Group A, C showed brown, smooth and translucent enamel surface, Only one rat in group D has one rat enamel translucent change with a little cloudy appearance; in 112 days, the chalk sample color changes were seen in the group B and G rats with enamel transparency turbidity. The brown and white horizontal grain appeared in group E, F rats with the 0.5~ 1 mm wide transparent area between the the grains. In overall, rats in group A, C, D had no significant difference compared with the baseline until 84 days. (3) The histopathological observation in rats teeth slice: comparing with group A, the growth lines in group B, group F and group G were obviously deepened, aggravating and more uneven structure arrangement. Group E also showed deepened and aggravating growth lines, but not obvious structure arrangement comparing with group A; However, the growth lines and structure arrangement in group C and D group had no significant changes.

Preschool children′s use of fluoride toothpaste could promote the generation of dental fluorosis in the high fluoride area. On the other hand, preschool childrens in Optimal fluorine area should strictly follow the guideline of usage of fluoride toothpaste to prevent generation of dental fluorosis together with daily life of the other intake of fluorine.