诱导大鼠下切牙氟斑牙模型所需饮水氟浓度及时间的筛选

目的通过观察不同浓度加氟饮水对大鼠下切牙釉质表面颜色变化及釉质发育的影响,筛选建立氟斑牙模型的合适实验时间及饮水氟浓度,为进一步研究氟斑牙的发病机理奠定实验基础。方法105只体重为210 g左右的SD雄性大鼠被随机分为4组,对照组15只用去离子水喂养,另外3组分别用含氟25mg/L5、0 mg/L及100 mg/L的氟化钠水喂养6周。分别在51、0、20、304、2 d等不同的时间点对每个大鼠下前牙唇侧面照相,然后每组分别处死一部分大鼠,分离下颌切牙、固定、脱钙并进行HE切片制作。结果正常鼠切牙颜色为橘黄色染色。在50 mg/L和100 mg/L氟化钠组成功地建立了下颌切牙氟斑牙模型,切牙釉质颜色呈现逐渐退变过程,由橘黄色变为浅黄色,白垩色,釉质的成釉细胞成多层排列。100 mg/L氟化钠组比50 mg/L组氟斑牙出现较早且更严重。而对照组和25 mg/L氟化钠组釉质表面颜色正常,成釉细胞排列整齐。结论50 mg/L和100 mg/L氟化钠水能成功的诱导不断生长的鼠切牙氟斑牙的产生。其釉质表面呈现白棕色条纹、白垩色等各种程度的颜色改变。25 mg/L氟化钠水喂养组在为期6周的实验中不产生明显的氟斑牙。

Different Doses of Sodium Fluoride in Drinking Water Induced Dental Fluorosis of Lower Incisors in SD Rats

Objective To set up the animal model of dental fluorosis in the lower incisors in Sprague-Dawley （SD）rats and investigate the changes of enamel surface color and amoblogine in rat incisor exposed to fluoride. Methods 105 male SD rats, average weight 200 g, were randomly divided into four groups. 15 rats were with distilled water （control group）. The other three group SD rats were rendered fluorotic by the administration of 25 rag/L, 50 mg/L, 100 mg/L sodium fluoride in their drinking water ad libitum. At the different time sites of 5,10,20,30,42 day, every rat was taken a photo of labial enamel surface of the lower incisor. Then some of the rats were sacrificed, manbibular incisors were removed, fixed, demineralized and sections prepared for H-E staining for light-microscopic morphometric observation. Results The normal color of enamel in rat incisor was yellow/yellow-orange. In this test, the fluorosis model was established successfully in incisors at 50 mg/L and 100 mg/L sodium fluoride groups. The enamel color in incisors were present white-chalk, straition and pitting, the ameloblasts arranged in multiple layers. The apperences of enamel fluorosis were ealier and more severity in 100 mg/L than 50 mg/L sodium fluoride group. The normal incisor color and the normal morphology of the ameloblasts were in the control group and the experimental group 25 mg/L NaF. Conclusion 50 rag/ L or 100 mg/L NaF may reduced the dental fluorosis successfully in continuous growth incisors in SD rats. the enamel surface in fluorosed rats exhibited opacity, white-chalk, and discoloration of varying extent. No obvious changes in ameloblasts and enamel surface apperenced in control group and 25 mg/L NaF group.