离子色谱法测定无水磷酸氢二钠中阴离子及不同级别产品质量比较

摘 要 目的：建立离子色谱法同时测定无水磷酸氢二钠中的氟离子、氯离子、硝酸根和硫酸根离子的含量,并评价不同级别无水磷酸氢二钠的质量状况。 方法: 采用Dionex IonPac AS18(4 mm×250 mm)色谱柱,以10,40 mmol·L-1 氢氧化钾淋洗液梯度洗脱,流速为1.0 ml·min -1 ,进样量为25 μl。 结果: 氟离子、氯离子、硝酸根和硫酸根离子质量浓度分别在0.02～0.40,0.01~0.80,0.06~1.00和0.10~5.00 μg·ml-1 范围内与峰面积均呈良好线性关系,r分别为0.999 5,0.999 7,0.999 9和0.999 5,平均回收率分别为92.26%,93.17%,99.80%,91.81%,RSD分别为0.87%,2.32%,3.07%,1.49%(n=6),供试品溶液在30 h内稳定。 结论: 本方法准确度高、重复性好,可用于测定无水磷酸氢二钠中的氟离子、氯离子、硝酸根和硫酸根离子的含量,为建立无水磷酸氢二钠的质量标准提供参考。     

西藏昌都县藏族居民氟铝总摄人量调查

目的调查西藏饮茶型氟中毒病区藏族成人总摄氟量、总摄铝量和经砖茶摄氟量、摄铝量。方法选择西藏昌都县卡若村进行流行病学调查、临床检查。采集主食、副食、饮水、砖茶、茶水（酥油茶）检测含氟量、含铝量,计算人均总摄氟量、总摄铝量和经砖茶摄氟量、摄铝量。结果卡若村成人临床氟骨症检出率55．88％,其中中度检出率35．29％,重度检出率5．88％。饮水含氟量0．10mg／L、含铝量（0．04±0．01）mg／L;砖茶含氟量（1139．0±138．7）mg／kg、含铝量（3888．5±474．1）mg／kg;砖茶饮料含氟量（3．68±1．44）mg／L、含铝量（9．31±4．11）mg／L,人均总摄氟量9．97mg／d,其中经砖茶摄入9．30mg／d,占总摄人量93．28％;人均总摄铝量41．50mg／d,其中经砖茶摄入29．25mg／d,占总摄入量70．48％;居民尿含氟量为（2．66＋1．39）mg／L、含铝量为（4．55±3．74）mg／L。结论西藏昌都县卡若村为饮茶型氟中毒重病区,与饮用砖茶含氟量、含铝量较高有关,可能是饮茶型氟铝联合中毒。     

Esthetic comparison of white-spot lesion treatment modalities using spectrometry and fluorescence

Objective:To compare the esthetic improvements of white-spot lesions (WSLs) treated by fluoride, casein phosphopeptide amorphous calcium phosphate (CPP-ACP), or resin infiltration.Materials and Methods:WSLs were created on human enamel and randomly assigned to four groups: NaF (500 ppm), CPP-ACP, resin infiltration (Icon), or distilled deionized water (DDW; control group). The color change (ΔE) of each specimen was measured with a Crystaleye spectrophotometer, and fluorescence loss (ΔQ) was measured by quantitative light-induced fluorescence (QLF), at different time points after treatment: baseline (0 weeks), 2 weeks, 4 weeks, and 6 weeks.Results:The ΔE and ΔQ baseline values for the four groups before the treatments did not differ significantly. Icon treatment improved the WSL color significantly and gave the lowest ΔE (2.9 ± 1.2 on average) compared with other treatments (P < .01). The Icon treatment also resulted in a significant change in the ΔQ of WSLs compared with baseline (P < .01). In the NaF and CPP-ACP treatment groups, ΔQ showed significant recovery compared with the baseline values only after 4 weeks after treatment (P < .05).Conclusions:Resin infiltration is more effective than NaF or CPP-ACP in providing esthetic improvement of WSLs.     

Evaluation of Streptococcus mutans adhesion to fluoride varnishes and subsequent change in biofilm accumulation and acidogenicity

Objectives

The aim of this study was to evaluate Streptococcus mutans adhesion to fluoride varnishes and subsequent change in biofilm accumulation and acidogenicity.

Methods

After producing fluoride varnish-coated hydroxyapatite discs using Fluor Protector (FP), Bifluorid 12 (BIF), Cavity Shield (CASH), or Flor-Opal Varnish White (FO), S. mutans biofilms were formed on the discs. To assess S. mutans adhesion to the discs, 4-h-old biofilms were analysed. To investigate the change in biofilm accumulation during subsequent biofilm formation, the biomass, colony forming units (CFU), and water-insoluble extracellular polysaccharides (EP) of 46-, 70-, and 94-h-old biofilms were analysed. To investigate the change in acidogenicity, pH values of the culture medium were determined during the experimental period. The amount of fluoride in the culture medium was also determined during the experimental period.

Results

BIF, CASH, and FO affected S. mutans adhesion (67–98% reduction) and subsequent biofilm accumulation in 46-, 70-, and 94-h-old biofilms. However, the reducing effect of the fluoride varnishes on the biomass, CFU count, water-insoluble EP amount, and acid production rate of the biofilms decreased as the biofilm age increased. These results may be related to the fluoride-release pattern of the fluoride varnishes. Of the fluoride varnishes tested, FO showed the highest reducing effect against the bacterial adhesion and subsequent biofilm accumulation.

Conclusions

Our findings suggest that if the results of these experiments are extrapolable to the in vivo situation, then reduced clinical benefit of using fluoride varnishes may occur with time.

Clinical significance

Fluoride varnish application can affect cariogenic biofilm formation but the anti-biofilm activity may be reduced with time.     

Caries-preventive effectiveness of fluoride varnish as adjunct to oral health promotion and supervised tooth brushing in preschool children: A double-blind randomized controlled trial

Objectives

To evaluate the effect of biannual fluoride varnish applications in preschool children as an adjunct to school-based oral health promotion and supervised tooth brushing with 1000 ppm fluoride toothpaste.

Methods

424 preschool children, 2–5 year of age, from 10 different pre schools in Athens were invited to this double-blind randomized controlled trial and 328 children completed the 2-year programme. All children received oral health education with hygiene instructions twice yearly and attended supervised tooth brushing once daily. The test group was treated with fluoride varnish (0.9% diflurosilane) biannually while the control group had placebo applications. The primary endpoints were caries prevalence and increment; secondary outcomes were gingival health, mutans streptococci growth and salivary buffer capacity.

Results

The groups were balanced at baseline and no significant differences in caries prevalence or increment were displayed between the groups after 1 and 2 years, respectively. There was a reduced number of new pre-cavitated enamel lesions during the second year of the study (p = 0.05) but the decrease was not statistically significant. The secondary endpoints were unaffected by the varnish treatments.

Conclusions

Under the present conditions, biannual fluoride varnish applications in preschool children did not show significant caries-preventive benefits when provided as an adjunct to school-based supervised tooth brushing with 1000 ppm fluoride toothpaste.

Clinical significance

In community based, caries prevention programmes, for high caries risk preschool children, a fluoride varnish may add little to caries prevention, when 1000 ppm fluoride toothpaste is used daily.     

窝沟封闭加局部用氟对龋高危儿童防龋效果观察

目的探讨窝沟封闭术联合局部应用含氟涂料对龋高危儿童龋齿的预防效果。方法选择6~8岁,乳牙龋牙数不低于4颗且至少有1颗深龋或需牙髓治疗的龋高危儿童51例为研究对象,双侧同颌第一恒磨牙作为受试牙,共146颗。采用自身半口对照方法,随机选择一侧受试牙应用窝沟封闭术,另一侧应用窝沟封闭术联合含氟涂料涂布,分别设为对照组和试验组。定期复查封闭剂保留情况和患龋情况。结果 12、18个月时,试验组龋齿发生率显著低于对照组（P〈0.05）,龋坏主要发生在封闭剂脱落的窝沟内。结论相比单一的龋病预防模式,联合应用窝沟封闭和含氟涂料,能更有效地降低龋高危儿童龋病发生率,减少龋病对儿童牙齿的破坏,值得临床推广应用。     

Focus on Fluorides: Update on the Use of Fluoride for the Prevention of Dental Caries

Improving the efficacy of fluoride therapies reduces dental caries and lowers fluoride exposure.BackgroundFluoride is delivered to the teeth systemically or topically to aid in the prevention of dental caries. Systemic fluoride from ingested sources is in blood serum and can be deposited only in teeth that are forming in children. Topical fluoride is from sources such as community water, processed foods, beverages, toothpastes, mouthrinses, gels, foams, and varnishes. The United States Centers for Disease Control and Prevention (CDC) and the American Dental Association (ADA) have proposed changes in their long standing recommendations for the amount of fluoride in community drinking water in response to concerns about an increasing incidence of dental fluorosis in children. Current research is focused on the development of strategies to improve fluoride efficacy. The purpose of this update is to inform the reader about new research and policies related to the use of fluoride for the prevention of dental caries.MethodsReviews of the current research and recent evidence based systematic reviews on the topics of fluoride are presented. Topics discussed include: updates on community water fluoridation research and policies; available fluoride in dentifrices; fluoride varnish compositions, use, and recommendations; and other fluoride containing dental products. This update provides insights into current research and discusses proposed policy changes for the use of fluoride for the prevention of dental caries.ConclusionsThe dental profession is adjusting their recommendations for fluoride use based on current observations of the halo effect and subsequent outcomes. The research community is focused on improving the efficacy of fluoride therapies thus reducing dental caries and lowering the amount of fluoride required for efficacy.     

Evaluation of fluoride release from experimental TiF4 and NaF varnishes in vitro

Fluoride varnishes play an important role in the prevention of dental caries, promoting the inhibition of demineralization and the increase of remineralization.

Objective

This study aimed to analyze the amount of fluoride released into water and artificial saliva from experimental TiF₄ and NaF varnishes, with different concentrations, for 12 h.

Material and Methods

Fluoride varnishes were applied on acrylic blocks and then immersed in 10 ml of deionized water and artificial saliva in polystyrene bottles. The acrylic blocks were divided in seven groups (n=10): 1.55% TiF₄ varnish (0.95% F, pH 1.0); 3.10% TiF₄ varnish (1.90% F, pH 1.0); 3.10% and 4% TiF₄ varnish (2.45% F, pH 1.0); 2.10% NaF varnish (0.95% F, pH 5.0); 4.20% NaF varnish (1.90% F, pH 5.0); 5.42% NaF varnish (2.45% F, pH 5.0) and control (no treatment, n=5). The fluoride release was analyzed after 1/2, 1, 3, 6, 9 and 12 h of exposure. The analysis was performed using an ion-specific electrode coupled to a potentiometer. Two-way ANOVA and Bonferroni''s test were applied for the statistical analysis (p<0.05).

Results

TiF₄ varnishes released larger amounts of fluoride than NaF varnishes during the first 1/2 h, regardless of their concentration; 4% TiF₄ varnish released more fluoride than NaF varnishes for the first 6 h. The peak of fluoride release occurred at 3 h. There was a better dose-response relationship among the varnishes exposed to water than to artificial saliva.

Conclusions

The 3.10% and 4% TiF₄ -based varnishes have greater ability to release fluoride into water and artificial saliva compared to NaF varnish; however, more studies must be conducted to elucidate the mechanism of action of TiF₄ varnish on tooth surface.     

氟对体外培养的血管内皮细胞增殖的影响

目的 观察不同浓度的氟对体外培养的人脐静脉血管内皮细胞增殖的影响.方法 利用二甲基噻唑二苯基四唑溴(MTT)比色法、流式细胞仪及免疫组织化学法观察不同浓度的(120、240、360、480、600、720、840、960 μmol/L)氟化钠染毒24 h对体外培养的人脐静脉血管内皮细胞增殖活性的影响.结果 氟化钠的浓度在120～240 μmol/L时,增殖细胞核抗原表达阳性率高于正常对照组(P＜0.01),240 μmol/L时的阳性率最高约为80%;吸光度(A)值和细胞分裂增殖指数(PI)值也高于正常对照组(P＜0.05,P＜0.01);360～480 μmol/L氟化钠染毒组上述指标与正常对照组差异无统计学意义(P＞0.05);当氟化钠的浓度增加到600 μmol/L以上时,增殖细胞核抗原的表达、A值及PI值均低于正常对照组(P＜0.05,P＜0.01),以960μmol/L时增殖抗原表达阳性率最低(约为20%),并且随着浓度增高上述指标呈下降趋势.结论 低浓度的氟化钠能促进脐静脉血管内皮细胞增殖活性,高浓度时抑制脐静脉血管内皮细胞的增殖活性,且随着氟浓度的增加,抑制作用逐渐增强.     

2006年山西省临汾市尧都区农村生活饮用水中氟含量的调查

目的 全面掌握山西省临汾市尧都区农村生活饮用水中氟含量的情况,并及时筛查出高氟水源,为改水决策的制订提供科学依据.方法 于2006年4-9月,在尧都区辖区内的12个乡镇175个行政村中,按东、西、南、北、中5个方位随机抽取1口水井作为采样点进行采样.按照GB 5750-1985《生活饮用水标准检验法》中氟离子选择电极法测定水样中的氟含量.按照GB 5749-1985《生活饮用水卫生标准》对检测结果进行评价.结果 共调查12个乡镇的175个行政村,生活饮用水中氟含量合格的行政村有80个,占45.7%;共采集水样873件(有1个行政村只有3口水井),合格478件,合格率为54.75%,水氟含量为0.24～5.44 mg/L,中位数为0.91 mg/L.水样合格率由高至低依次为:金殿镇(84.29%)＞吴村镇(78.67%)＞刘村镇(66.83%)＞贺家庄(66.67%)＞屯里镇(62.86%)＞乔李镇(50.00%)、土门镇(50.00%)、大阳镇(50.00%)、县底镇(50.00%)＞贾得乡(43.84%)＞尧庙镇(26.67%)＞段店乡(12.00%).不同井深水氟含量合格率间比较,经x2检验,差异有统计学意义(x2=322.066,P＜0.01);且水氟含量合格率随着井深的增加而升高,呈正相关关系(r=0.517 7,P＜0.01).结论 山西省临汾市尧都区属于中、重度地氟病病区,建议应加大对高氟区的改水降氟力度,让当地群众早日脱离高氟水的危害.