不同氟浓度涂膜对牙釉质表面显微硬度的影响

作者观察应用含不同浓度氟化钠涂膜后牙釉质表面显微硬度值的改变情况。实验将釉质随机分为A、B、C三组。先测出实验之前的显微硬度值。然后在这三组釉质表面分别涂上0．5％、1．5％、2．7％的氟化钠涂膜24小时．再测显微硬度。结果；三组不同浓度氟化钠涂膜均使牙釉质显微硬度值有显著提高。与处理前比较，具高度显著性差异。A组含0.5%氟化钠涂膜其显微硬度值的增加率仅是其它两组的一半，而B、C两组高浓度氟化钠涂膜之间其硬度值的增加率又几乎相同。这表明，在达到一定的氟浓度后，其硬度值不再增加。作者认为，使用含1.5%氟化钠涂腹对预防龋齿较为理想。     

牙釉质显微硬度测定在龋病研究中的应用

牙釉质显微硬度是用显微压痕技术测得的釉质硬度,它对测定釉质早期脱矿时矿物质的变化有高灵敏性,作为研究釉质龋的指标之一,在龋病的病因、预防及治疗等方面的研究上均有重要意义。本文对牙釉质显微硬度的测定在龋病研究中的作用进行回顾和总结。     

饮料对牙釉质表面显微硬度影响的研究

目的：研究不同饮料对牙釉质表面显微硬度的影响。方法：用不同种类饮料处理牙釉质后,采用维氏显微硬度仪测定牙釉质的处理前和处理后的1－7d表面显微硬度的改变。结果：饮料能引起牙釉质表面显微硬度的降低,降低的程度与饮料的种类有关,不同种类饮料导致牙釉质表面显微硬度降低的强度不同,差异有统计学意义（P＜0.001）。随时间的延长,表面显微硬度也随之降低（P＜0.001）。结论：饮料对牙釉质都具有脱矿作用,脱矿随饮料接触牙齿时间的延长而增加。     

Fluor Protector对酸性果汁饮料致牙釉质表面显微硬度影响的实验研究

目的 :研究FluorProtector对由于酸性果汁饮料导致牙釉质表面显微硬度的影响。方法 :采用维氏显微硬度仪测定牙釉质块经FluorProtector和 0 .1%氟化钠预处理后 ,再经酸性果汁饮料浸泡。饮料浸泡的方式为 5次 /d ,5min/次× 7d。 7d后测定牙釉质表面显微硬度变化。结果 :经FluorProtector和 0 .1%氟化钠预处理的牙釉质再经果汁饮料浸泡 ,表面显微硬度降低的程度低于直接用饮料浸泡的对照组。FluorProtector处理组的牙釉质表面显微硬度降低的程度最小。三组之间的差异有统计学意义 ( p <0 .0 5 )。 结论 :酸性果汁饮料能导致牙釉质脱矿 ,使牙釉质表面显微硬度降低。FluorProtector和氟化钠能抵抗牙釉质脱矿。FluorProtector的作用优于 0 .1%氟化钠。     

氟化钠泡沫和凝胶对牛牙釉质表面显微硬度的影响

目的：评价氟化钠泡沫和氟化钠凝胶对牛牙釉质表面显微硬度的影响。方法：采用新鲜牛牙釉质块为标本,应用显微硬度计测量分别采用氟化钠泡沫、氟化钠凝胶进行矿化试验和抗龋试验后的釉质块表面显微硬度。结果：试验前和矿化试验后的釉质表面显微硬度相比,使用氟化钠泡沫组增加率为54．41％－21．32％,使用氟化钠凝胶组增加率为47．26％－25．36％。试验前和抗龋试验后的釉质表面显微硬度相比,使用氟化钠泡沫组降低率为24．88％－33．19％,使用氟化钠凝胶组降低率为30．97％－38．66％,而空白对照组降低率为41．26％。结论：氟化钠泡沫对釉质表面显微硬度的影响和氟化钠凝胶相比无显著差异,用氟化钠泡沫改善釉质表面显微硬度与氟化钠凝胶具有相同效果。     

牙釉质显微硬度测定在龋病研究中的应用

牙釉质显微硬度是用显微压痕技术测得的釉质硬度,它对测定釉质早期脱矿时矿物质的变化有 高灵敏性,作为研究釉质龋的指标之一,在龋病的病因、预防及治疗等方面的研究上均有重要意义。本文对牙釉质显微硬度的测定在龋病研究中的作用进行回顾和总结。     

上颌第二乳磨牙釉质显微硬度测量

硬度是牙釉质重要的物理性能指标之一，显微硬度即显微压痕硬度的简称。在正常或脱矿的釉质中，显微硬度能反映釉质的矿化程度及矿物质含量的多少。我们通过测量正常上颌乳磨牙釉质各部位的显微硬度，探讨牙易患龋部位与非易患龋部位间釉质矿化程度是否存在差异，以期为乳牙釉质显微硬度的研究提供基础资料。     

镧、钙、氟对釉质脱矿的影响——显微硬度测定

目的：比较镧,钙,氟对人牙釉质酸蚀脱矿影响,为镧的应用研究提供实验依据,方法：酸性凝胶化学致龋,测定釉质脱矿区剖面显微硬度,逐步单因素方差分析其显微硬度值,结果：釉质表层下25－125um范围内,镧处理组,氟处理组的硬度值高于对照组,25－75um范围内,洎 的硬度值高于钙处理组,50－150um范围内,钙处理组的硬度值高于对照组,氟处理组的硬度值高于镧处理组,结论：脱矿凝胶中加入1g/L的Ca2 ,La3 ,F-均阻止釉质硬度的下降,氟的作用最强,钙的作用最弱,镧的处理界于氟和钙之间。     

镧、钙、氟对釉质脱矿的影响——显微硬度测定

目的 :比较镧、钙、氟对人牙釉质酸蚀脱矿影响 ,为镧的应用研究提供实验依据。方法 :酸性凝胶化学致龋 ,测定釉质脱矿区剖面显微硬度 ,逐点单因素方差分析其显微硬度值。结果 :釉质表层下 2 5～ 15 0 μm范围内 ,镧处理组、氟处理组的硬度值高于对照组 ;2 5～ 75 μm范围内 ,镧处理组的硬度值高于钙处理组 ;5 0～ 15 0 μm范围内 ,钙处理组的硬度值高于对照组 ,氟处理组的硬度值高于镧处理组。结论 :脱矿凝胶中加入 1g/L的Ca2 +、La3 +、F-均阻止釉质硬度的下降 ,氟的作用最强 ,钙的作用最弱 ,镧的作用界于氟和钙之间。     

不同氟处理方法釉质表面超微结构观察

目的观察托槽粘结前应用不同方法氟处理以及去托槽后，釉质表面超微结构的变化。方法挑选因正畸需要而拔除的96颗双尖牙，随机分为对照组，酸蚀前加氟组，酸蚀液中加氟组，酸蚀后加氟组，每组牙釉质经酸蚀和不同方法氟处理后做扫描电镜观察并进行统计学分析。结果酸蚀中加氟组和酸蚀后加氟组釉质表面产生的反应物较多且去托槽后残留较多。结论酸蚀剂中加氟和酸蚀后加氟方法可能对固定正畸治疗中防止釉质脱矿有较好的效果。     

体外应用氟化物对牙酸蚀症再矿化效果的评价-显微硬度测定

目的 用显微硬度测量法研究氟化物对碳酸饮料酸蚀后的乳牙釉质的再矿化作用.方法 收集临床拔除的滞留第二乳磨牙共16颗,制成牙釉质样本.经碳酸饮料浸泡,每天2次,每次10分钟,共5天后,分为对照组(A组)、2%氟化钠溶液组(B组)、含1.23%氟离子凝胶组(C组)和含低氟过饱和钙磷溶液矿化液组(含氟10ppm)(D组)四组,每组16个牙块.经不同的氟化物处理釉质表面,每天1次,每次2分钟,共5天.分别在酸蚀前、酸蚀后和再矿化后用显微硬度计测定釉质表面硬度.数据使用SPSS10.0统计软件包进行单因素方差分析(ANOVA).结果 饮料酸蚀后的牙釉质表面硬度值明显下降.与对照组相比,经2%氟化钠溶液和1.23%氟离子凝胶组处理后的牙釉质表面硬度值均比处理前显著上升(分别为P=0.031和P=0.017),这两组之间的差异无显著性;矿化液处理后的牙釉质表面硬度值无显著变化(P=0.894).结论 显微硬度测定实验显示高浓度的氟制剂2%氟化钠溶液和含1.23%氟离子凝胶能够显著地促进酸蚀釉质再矿化;低氟浓度矿化液在短时间内对酸蚀釉质再矿化作用不明显.     

Effect of fluoride containing bleaching agents on enamel surface properties

OBJECTIVES: To evaluate the effects of fluoridated bleaching agents and post-bleaching fluoridation treatment on the whitening efficiency and microhardness of bovine enamel. METHODS: Twenty five freshly extracted bovine incisors were cut into halves, embedded and then divided into the following five groups: Group 1, untreated controls; Group 2, treatment with 10% carbamide peroxide (CP) bleaching agent; Group 3, treatment with 10% CP followed by a 0.9% sodium fluoride gel application, Group 4, treatment with 10% CP containing 0.11% fluoride; Group 5, treatment with an experimental bleaching agent consisting of 10% CP and 0.37% fluoride. Groups 2-5 were treated 8h per day for 14 days then immersed in saliva for 2 weeks. Enamel morphology changes were evaluated under SEM on Day 14. Changes in enamel color and microhardness were evaluated on Days 7 and 14, and compared with the baseline data. Additionally, microhardness was determined on post-bleaching Days 21 and 28. RESULTS: After 2 weeks, an erosion pattern was noted on the specimens in Groups 2 and 3. Groups 4 and 5 showed a milder demineralized pattern. All the bleached enamel specimens revealed increased whiteness and overall color value. Groups 2 and 3 showed significantly decreased enamel microhardness compared to their baseline data. The specimens treated with fluoridated bleaching agents showed relatively less reduction in enamel microhardness than those treated with nonfluoridated agents during the bleaching treatment. CONCLUSIONS: The fluoridated bleaching agents produced less demineralization of surface morphology and microhardness. The addition of fluoride did not impede the whitening effect.     

Effect of low level fluoride on demineralization kinetics of human dental enamel

The purpose of this study was to examine the effect of fluoride levels similar to those reported for saliva from low fluoridated and high fluoridated water areas on the demineralization of human permanent enamel. An adaptation of the method described by Robinson et al. was used. Sections of sound enamel were immersed in a vial containing demineralizing solution [2.0 mM Ca(NO₃)₂, 1.2 mM KHPO₄ in 50 mM acetic acid, pH 4.8] for 1 hour. The demineralizing solution contained 0, 0.02 or 0.05 ppm fluoride, added as NaF was prepared. Twenty microliters aliquots were taken from the demineralizing solution at the time point up to 1 hour, with a sampling frequency bias towards the early time point. The phosphate content of the removed sample was determined by colorimetry. When the mineral loss curves for fluoridated and non-fluoridated demineralizing solutions were compared, there were significant differences between both groups. There was a decrease in the net mineral loss when fluoride was used. This result suggested that salivary fluoride levels of 0.02 ppm and 0.05 ppm had a protective effect against demineralization.     

Influence of fluoride concentration and ethanol pre-treatment on the reduction of the acid susceptibility of enamel

Objective

To determine the association between KOH-soluble and structurally bound fluoride uptake and the erosion resistance of enamel, respectively. Additionally, the effect of enamel pre-treatment with ethanol before fluoridation was assessed.

Methods

Sixty bovine incisors (4 specimens/tooth) were randomly allocated to six groups (A-F). Samples 1 and 2 remained untreated, serving as control at baseline. Pre-treatment of the samples was performed for 5 min with 99% ethanol (groups A, B and C) or physiologic saline (groups D, E and F). Samples 3 and 4 were treated either with 0.5% (groups A and D), 1.0% (groups B and E) or 1.5% (groups C and F) fluoride solution. In samples 1 and 3, uptake of KOH-soluble and structurally bound fluoride was determined. Samples 2 and 4 were used for the determination of acid susceptibility by immersion in 1 ml HCl for 30 s. Calcium release into HCl was assessed by atomic absorption spectroscopy. Differences between the groups were calculated by unpaired t-tests (p < 0.05).

Results

Mode of pre-treatment showed no influence on fluoride acquisition. KOH-soluble and structurally fluoride uptake increased with increasing fluoride concentrations. Highest acid resistance was observed after treatment with 1% fluoride solution for both kinds of pre-treatment followed by 1.5% and 0.5% fluoride solution.

Conclusion

Dose-dependency was observed for enamel fluoride acquisition but not for acid resistance.     

Influence of carbamide peroxide on enamel fluoride uptake

OBJECTIVE: Aim of the study was to evaluate the influence of carbamide peroxide (CP) on enamel fluoride uptake by comparing enamel fluoride uptake from a 1% amine fluoride (AmF) gel with the fluoride acquisition from a 10% carbamide peroxide agent supplemented with 1% AmF. MATERIALS AND METHODS: Three enamel cylinders (4mm in diameter) were prepared from the buccal surfaces of 60 bovine incisors. One sample of each tooth was used for determination of baseline fluoride content of the respective tooth. The two remaining samples were allocated to the experimental series 1 or 2, respectively. Each series consisted of five experimental groups (A-E, n=12) and differed with respect to the length of the treatment period with the gels (A-D). The experimentally designed gels (pH 5.5) used in the study were as follows: A (10% CP), B (10% CP, 1% F(-) as AmF), C (1% F(-) as AmF), D (no CP, no F(-)) and were formulated on the same basis. The enamel samples were covered for 4h with the respective gel at 37 degrees C and were then transferred to artificial saliva for 20 h (series 1). The samples of group E served as controls and were not treated with a gel. In series 2, treatment with the gels and storage in saliva was conducted seven times. Finally, the samples were assessed for KOH-soluble and structurally bound fluoride. RESULTS: Only the enamel samples treated with the fluoridated bleaching gel (group B) and with the amine fluoride gel (group C) exhibited significant fluoride acquisition. Thereby, both gels showed significantly lower uptake in series 1 as compared to series 2. Both KOH-soluble and structurally bound fluoride acquisition was significantly higher in group C than in group B. CONCLUSION: Treatment with a carbamide peroxide gel supplemented with amine fluoride causes less fluoride acquisition in enamel than a pure amine fluoride gel. Under the conditions of the study, it is assumed that carbamide peroxide seems to influence enamel fluoride uptake.     

饮料对牙釉质表面硬度的影响的体外实验研究

目的　本实验用显微硬度测量法,定量研究和评估人离体牙釉质在酸性饮料中的硬度变化,比较牙釉质在饮料中浸泡时间及浸泡频率对釉质表面硬度的影响。方法　实验设人工唾液组(对照组)和可口可乐组、橙汁组,共9组,每组1 0个牙块。浸泡在饮料中1次/天、3次/天、7次/天,均在37℃恒温箱中进行,每次1 0分钟,共进行4天。在0天、2天、4天测量牙釉质表面硬度(韦氏法)。结果　①对照组实验前后无显著性差异。②可口可乐组1次/天和7次/天在4天的硬度值为1 6 2±5 0和6 8±4 0 ,有显著性差异(P =0 .0 1 ) ;橙汁组1次/天和7次/天在4天的硬度值为2 1 0±6 3和93±34,有显著性差异(P =0 .0 0 1 )。③此外,可口可乐组和橙汁组牙釉质表面的平均硬度从0天(基线值)到2天均有一个急剧的下降过程并持续至第4天(各为0天335±34,2天1 4 3±84 ,4天1 0 4±5 9和0天343±2 8,2天1 85±72 ,4天1 5 4±74 ) ,两饮料组之间无显著性差异。结论　可口可乐和橙汁可使牙釉质表面硬度降低,浸泡的时间和频率起主要作用。这对于儿童合理使用饮料并预防龋齿有临床指导意义。     

A qualitative and quantitative investigation into the effect of fluoride formulations on enamel erosion and erosion-abrasion in vitro

Objectives

To investigate the effect of a single application of highly concentrated SnF₂ and NaF solutions and a NaF/CaF₂ varnish on human enamel subjected to hydrochloric acid erosion and tooth brush abrasion.

Methods

Forty enamel samples were prepared from human third molars and NaF (9500 ppm, pH 8.0), SnF₂ (9500 ppm, pH 2.6) solutions; Bifluorid10^® varnish (42,500 ppm, NaF 5%, CaF₂ 5%) and deionized water (control) was applied to the enamel. Following this three, six and nine cycles of erosion [1 cycle = erosion (0.01 M HCl, pH 2.2, 2 min) + artificial saliva (1 h, pH 7.0)] and erosion-abrasion [1 cycle = erosion (0.01 M HCl, pH 2.2, 2 min) + artificial saliva (1 h, pH 7.0) + abrasion (120 linear strokes in artificial saliva from Tepe medium soft brushes 200 g loading)] were carried out. The fluoride treated enamel was analysed using Knoop microhardness, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).

Results

For erosion alone, there was significantly less microhardness reduction in the Bifluorid10^® group after three and six cycles of erosion (P < 0.05), however no other groups showed statistically different hardness (P > 0.05). The EDS analysis showed that only the Bifluorid10^® group had any detectable fluorine following erosion and erosion-abrasion (0.1 wt.% and 0.2 wt.% fluorine respectively). The surface fluorine was found to have been removed after erosion and erosion-abrasion for all other surface treatments. Although precipitates were observed after application of the surface treatments, following erosion-abrasion, no visible surface effects from any fluoride preparation remained.

Conclusions

Enamel surface precipitates from application NaF, SnF₂ solutions appear to not be able to provide protection against gastric erosion and tooth brush abrasion. The NaF/CaF₂ varnish provided limited protection against erosion but the role for such varnishes in gastric erosion and tooth brush abrasion remains uncertain.