多乐氟、护牙素及含氟牙膏促进釉质再矿化的体外研究

目的:比较多乐氟、护牙素和含氟牙膏促进脱矿釉质再矿化的效果。方法:将40个牛牙釉质块人工龋试样随机分为4组(n=10),A组(对照组)置于人工唾液中浸泡12 d;B组(多乐氟组)釉质表面涂覆多乐氟涂膜,12 h后去除涂膜,置于人工唾液中浸泡12 d;C组(护牙素组)釉质表面涂覆护牙素1 min后,置于人工唾液中浸泡12 d;D组(含氟牙膏组)分别于每天早、晚将样本浸泡于含氟牙膏浆3 min,其余时间浸泡于人工唾液中,共12 d。脱矿前及处理前后,用硬度计测定各组釉质表面的显微硬度,计算其表面硬度恢复率(SMHR%);SEM观察表面结构。结果:SEM观察发现,B、C、D组再矿化处理前后釉质表面有新形成的羟基磷灰石晶体沉积。A、B、C、D组的SMHR(%)分别为20.43±5.91、60.55±14.05、67.69±11.74、52.82±3.61;除B、C组无统计学差异(P>0.05),其他各组间两两相比均有统计学差异(P<0.05)。结论:含氟材料或亚稳定无定形磷酸钙材料(护牙素)均可显著促进脱矿釉质的再矿化,护牙素的效果最好。     

多乐氟预防碳酸饮料对乳牙釉质脱矿的体外研究

目的:证实多乐氟能预防碳酸饮料对乳牙牙釉质的脱矿作用。方法:将72个乳牙釉质块随机分成4组,每组18块。人工唾液为对照组(A);可乐碳酸饮料浸泡组(B);多乐氟处理后可乐浸泡组(C);氟化泡沫处理后可乐浸泡组(D)。A组试件不作处理,B组试件浸泡于可乐中30 min,取出后用去离子水冲洗干净放置约4 min,再次浸泡于可乐中30 min,如此循环直至12 h。实验C、D组釉质块分别浸在多乐氟、氟化泡沫涂抹4 min后,后续处理同B组。上述处理后试件分别用扫描电镜、能谱分析仪检测釉质表面的形态变化及Ca²⁺、P³⁺含量( 重量百分比)。结果:对A组相比,可乐浸泡可致乳牙釉质表面脱矿;氟化物处理后可降低釉质表面的脱矿程度,并使晶体颗粒体积变大,其表面Ga²⁺、P³⁺含量的降低程度也低于B组,差异有统计学意义(P<0.05)。结论:多乐氟可抑制乳牙釉质在碳酸饮料中的脱矿,效果较好,并能促进其再矿化。     

CPP-ACP与不同浓度氟促进釉质再矿化的研究

目的：探讨酪蛋白磷酸多肽-无定形磷酸钙(casein phosphopeptide-amorphous calcium phosphate,CPP-ACP) 与不同浓度氟离子联合应用对脱矿釉质再矿化的作用。方法：取正畸拔除的健康前磨牙30颗,乳酸凝胶法制备人工早期釉质脱矿后, 随机分为对照组(5% CPP-ACP组)、实验组1(5% CPP-ACP+500 mg/L F-组)和实验组2(5% CPP-ACP+900 mg/L F-组),采用MH-5型显微硬度仪测量处理前、后釉质标本的显微硬度,采用SPSS 18.0软件包对数据进行统计学分析。结果：显微硬度测量显示,实验组2牙釉质的表面显微硬度变化显著高于实验组1(P<0.05)及对照组(P<0.01)。结论：CPP-ACP能够促进脱矿釉质再矿化,氟对其有加强协同作用。在一定范围内,氟浓度越高,协同作用越好。     

氟纳米羟基磷灰石对早期釉质龋再矿化影响的研究

目的:研究氟纳米羟基磷灰石对早期釉质龋再矿化的影响,比较它与纳米羟基磷灰石、氟化钠和人工唾液的再矿化效果。方法:选取新鲜拔出的牛切牙40颗,制成人工龋模型,露出唇侧面,其余部分涂布双层指甲油。置于盛有脱矿液的容器中37℃脱矿3d,使用显微硬度仪测量脱矿后釉质的显微硬度。扫描电镜下观察脱矿后的釉质表面的平滑状态。然后随机分为4组。用软毛刷将相应试剂涂刷在釉质表面,3次/d,3～4min/次。人工唾液组直接将釉质块浸泡其中。10d后进行显微硬度和扫描电镜观察。实验前后统计采用配对t检验。结果:氟纳米羟基磷灰石组的显微硬度较脱矿后和对照组硬度值增加,有统计学意义(P<0.05),扫描电镜观察釉质表面变平滑。结论:氟纳米羟基磷灰石对早期釉质龋的再矿化效果较好。     

玻璃离子保护膜与氟保护漆对牙釉质脱矿的预防和再矿化作用

目的: 比较玻璃离子保护膜与氟保护漆对牙釉质脱矿的预防和再矿化作用。方法: 选择122颗正畸减数拔除的前磨牙,制成釉质块,随机选择2个,进行扫描电镜（SEM）观察,其余用于两部分实验。①釉质脱矿预防实验 （实验A）—选择60个釉质块,随机分为3组（n=20）,分别使用玻璃离子保护膜（A1组）、氟保护漆（A2组）,对照组（A3组）不予处理;②釉质再矿化实验（实验B）—选择60个釉质块,预脱矿72 h后,随机分为3组(B1、B2、B3,n=20),处理方法同预防釉质脱矿各组。实验A、B共6组样本均经人工脱矿液和人工唾液交替pH循环处理30 d。采用SEM观察釉质表面形貌,显微硬度计测定釉质表面显微硬度（SMH）变化,X线能谱分析仪分析釉质表面钙磷比。采用SPSS 26.0软件包对数据进行统计学分析。结果: 釉质脱矿预防实验,未作处理的牙釉质表面平坦、均匀,A1组釉质表面基本完整,A2组釉质表面可见大量片状沉积物,A3组呈现典型的脱矿导致的蜂窝状结构。各组间ΔSMH两两比较,A1组A2组>A3组(P<0.05)。釉质再矿化实验,SEM结果显示,B1、B2组均有沉积物附着于釉质表面,B3组釉质表面凹凸不平,呈蜂窝状。各组间ΔSMH两两比较,B1组>B2组>B3组(P<0.05)。钙磷比值依次为B1组>B2组>B3组(P<0.05)。结论: 玻璃离子保护膜和氟保护漆均可预防和治疗牙釉质脱矿,玻璃离子保护膜由于其耐磨、持久,具有更好的保护和再矿化作用。     

不同浓度氟泡沫对牙釉质表面显微硬度的影响

目的：观察不同浓度氟泡沫对脱矿牙釉质表面显微硬度值的影响。方法：将牙釉质块随机分为A，B两组，脱矿30min后在两组牙釉质表面分别涂布0．9％中性氟化钠氟泡沫和1．23％酸性氟磷酸盐氟泡沫4min，并在人工唾液中浸泡30min,24h后测定牙釉质表面显微硬度值，结果：两组不同浓度氟泡沫涂布后牙釉质表面显微硬度值均有显著提高，人工唾液浸泡30min和24h，涂布1．23％酸性氟磷酸盐氟泡沫组的牙南表面显微硬度值均高于0．9％中性氟化钠氟泡沫组，统计学检验30min时有显著差异，24h无差异。结论：两种浓度的氟泡沫均可使牙釉质表面显微硬度显著提高，1．23％酸性氟磷酸盐氟泡沫影响效果优于0．9％中性氟化钠氟泡沫。     

成膜基质对氟化物涂膜提高釉质抗脱矿性能的影响

目的:评价成膜基质材料对氟化物涂膜提高釉质体外抗脱矿性能的影响。方法:在制备的5组牛牙釉质试样表面分别涂布以5种成膜基质(渗透型丙烯酸树脂、珂巴树脂、聚合松香、聚乙烯醇缩丁醛、甲基丙烯酸共聚树脂)配制的5种氟涂膜材料,另有一组不做处理,为对照组。在保湿12 h后,除去涂膜,然后对所有试样进行脱矿-再矿化循环处理7 d,之后纵向剖切试样,测定纵剖面显微硬度(HK),并用扫描电镜观察釉质处理面。结果:在釉质表面下90μm深度范围内的相同深度,所有涂膜组釉质的显微硬度均明显高于对照组(P<0.05);在釉质表面下50μm深度范围内的相同深度,渗透型丙烯酸树脂组的釉质硬度大于其它4组(P<0.05);各组釉质表面在扫描电镜下呈现不同特点的脱矿形式。结论:成膜基质材料对氟化物涂膜提高釉质体外抗脱矿性能有明显影响,含渗透型丙烯酸树脂的氟涂膜对抗釉质脱矿效果更佳。     

人氟斑牙早期龋再矿化的初步研究

目的研究离体氟斑牙早期龋模型经再矿化处理后,釉质表面显微硬度及微观形貌的变化。方法应用离体氟斑牙制备釉质样本40个,经酸蚀凝胶人工龋实验脱矿后,1.0%酪蛋白磷酸肽-磷酸钙（CPP-CP）再矿化液再矿化。采用显微硬度计测定各样本脱矿前后及再矿化后的显微硬度值。采用体视显微镜、偏光显微镜、透射显微镜以及扫描电镜观察釉质表面微观形貌。结果脱矿前,釉质表面显微硬度值为（241.53±21.31）kHV;脱矿后,表面显微硬度下降到（175.76±24.99）kHV（P＜0.05）。其表面硬度损失百分比（%SMHD）为（27.23±4.79）％,表现为类似早期龋的表层下脱矿;再矿化后,表面显微硬度提高到（210.17±21.48）kHV（P＜0.05）,其表面显微硬度恢复的百分比（%SMHR）为（52.32±4.23）％,主要表现为表层下再矿化。结论再矿化处理对治疗氟斑牙早期龋有较好的临床效果。     

局部用奥威尔凝胶对酸性饮料导致年轻恒牙脱矿和再矿化的影响

目的比较局部使用奥威尔凝胶或氟保护漆对年轻恒牙抵抗饮料酸蚀及酸蚀后脱矿釉质再矿化的影响。方法观测年轻恒牙的釉质经饮料浸泡后再经奥威尔凝胶或氟保护漆局部处理,或奥威尔凝胶及氟保护漆处理后再经饮料浸泡的表面显微硬度（SMH）变化;应用扫描电子显微镜（SEM）观察各组釉质的表面形态。结果饮料浸泡后再经奥威尔凝胶或氟保护漆局部处理的年轻恒牙,其釉质的SMH明显增加（P<0.05）,奥威尔凝胶组的SMH高于氟保护漆组（P<0.05）。奥威尔凝胶或氟保护漆处理釉质表面后再经饮料浸泡,奥威尔凝胶组的SMH高于氟保护漆组（P<0.05）。SEM下可见各组釉质表面经饮料及奥威尔凝胶或氟保护漆处理后呈现不同程度的釉质溶解和再矿化。结论年轻恒牙釉质表面应用奥威尔凝胶可以增强釉质对饮料酸蚀的抵抗作用,促进脱矿釉质的再矿化。     

光学相干断层成像检测牙釉质表层脱矿与再矿化的实验研究

目的利用光学相干断层成像技术(OCT)观察不同制剂对年轻恒牙釉脱矿和再矿化效果的影响。方法 将正畸拔除的年轻恒前磨牙制成60个釉质块,随机均分为4组。每天进行如下处理:A组蒸馏水湿敷30min;B组含氟牙膏湿敷30min;C组护牙素湿敷30min;D组多乐氟湿敷30min,置于脱矿液1.5h,最后置于人工唾液中22h。每个步骤间用去离子水冲洗实验样品。实验周期重复30天。在处理前和第 7、15、30天,使用扫频光源OCT完成对样本的扫描和成像,同时使用显微硬度计测量各样本表面的显微硬度。结果 釉质脱矿深度:7天后,A组与其他各组相互比较,差异有统计学意义( P <0.05),B、C、D组组间比较差异无统计学意义( P >0.05)。30天后,C组和D组比较,差异无统计学意义( P >0.05),其余各组之间两两比较,差异均有统计学意义( P <0.05)。显微硬度测量:30天后,各处理组较处理前显微硬度值降低,A组显微硬度值最低,C组与D组显微硬度值高于B组,且差异有统计学意义( P <0.05)。C组和D组间釉质块显微硬度值差异无统计学意义( P >0.05)。结论 OCT可以较准确的显示釉质脱矿部位,在早期龋的诊断方面具有临床意义。护牙素和多乐氟均能有效的抑制牙釉质表面脱矿。     

Evaluation of fluoride release from commercially available fluoride varnishes.

BACKGROUND: The authors conducted a study to evaluate the fluoride released from two fluoride varnishes: Duraphat (Colgate-Palmolive Co., New York) and Duraflor (Pharmascience Inc., Montreal). Fluoride-release information for these commercially available dental products has not been available to clinicians treating children at risk of developing dental caries. METHODS: The authors painted enamel slabs from primary molar teeth with 30 milligrams of two varnishes: nine samples received Duraphat, nine received Duraflor and five samples served as controls. The samples were immersed in buffered calcium phosphate solution (pH, 6.0) to simulate the oral environment, and the amount of fluoride released was measured weekly for six months. RESULTS: From week 4 to the end of the study, Duraphat released significantly more fluoride than Duraflor. Duraflor continued releasing fluoride until week 19, while Duraphat released fluoride until week 28. The authors found greater variability in the release of fluoride from the Duraflor samples than from the Duraphat samples. Two-thirds of the fluoride was released from both products by the end of the study. CONCLUSIONS: Both varnishes released fluoride for five to six months. However, the two products exhibited differences in their release kinetics. CLINICAL IMPLICATIONS: These findings show that either of the fluoride varnishes may maintain a high level of fluoride in plaque fluid around primary teeth over a long period, but that the availability of fluoride may vary among tubes of the same product and between the two products themselves.     

Deposition of fluoride on enamel surfaces released from varnishes is limited to vicinity of fluoridation site

The aim of the in-situ study was to determine fluoride uptake in non-fluoridated, demineralized enamel after application of fluoride varnishes on enamel samples located at various distances from the non-fluoridated samples. All enamel samples used were demineralized with acidic hydroxyethylcellulose before the experiment. Intra-oral appliances were worn by ten volunteers in three series: (1, Mirafluorid, 0.15% F; 2, Duraphat, 2.3% F and 3, unfluoridated controls) of 6 days each. Each two enamel samples were prepared from 30 bovine incisors. One sample was used for the determination of baseline fluoride content (BFC); the other was treated according to the respective series and fixed in the intra-oral appliance for 6 days. Additionally, from 120 incisors, each four enamel samples were prepared (one for BFC). Three samples (a–c) were placed into each appliance at different sites: (a) directly neighboured to the fluoridated specimen (=next), (b) at 1-cm distance (=1 cm) and (c) in the opposite buccal aspect of the appliance (=opposite). At these sites, new unfluoridated samples were placed at days 1, 3 and 5, which were left in place for 1 day. The volunteers brushed their teeth and the samples with fluoridated toothpaste twice per day. Both the KOH-soluble and structurally bound fluoride were determined in all samples to determine fluoride uptake and were statistically analyzed. One day, after fluoridation with Duraphat, KOH-soluble fluoride uptake in specimen a (=next) was significantly higher compared to the corresponding samples of both the control and Mirafluorid series, which in turn were not significantly different from each other. At all other sites and time points, fluoride uptake in the enamel samples were not different from controls for both fluoride varnishes. Within the first day after application, intra-oral-fluoride release from the tested fluoride varnish Duraphat leads to KOH-soluble fluoride uptake only in enamel samples located in close vicinity to the fluoridation site.     

Fluoride and calcium release from peppermint-flavored fluoride varnish containing dicalcium-phosphate-dihydrate coated with xylitol

Bakground: Fluoride varnish with high initial fluoride and calcium release can help patients with high-risk caries. Ample quantities of free fluoride and calcium ions in the oral cavity can enhance enamel remineralization. This study aimed to investigate the effect of dicalcium phosphate dihydrate coated with xylitol (DCPD-xylitol), in fluoride varnish, on the release of fluoride and calcium ions in the oral cavity.Materials and methodsDCPD powder with xylitol was synthesized by preparing a 60% xylitol solution and mixed it with DCPD solution. The mixture was stirred for 1 h at room temperature and dried at 80 °C for 18 h to reduce the water content. Then, the powder was used in the formulation of peppermint-flavored fluoride varnish as an active agent. The amounts of fluoride and calcium ion released in deionized water at 37 °C for 6 h were assessed with an ion-selective electrode. The cumulative fluoride and calcium ion release data were analyzed using one-way analysis of variance (ANOVA) and the post hoc Tukey test with α = 0.05.ResultsThe results showed that the addition of DCPD coated with xylitol provided better bioavailability of the ions than DCPD without coating. Peppermint-flavored fluoride varnish (PFFV) with DCPD-xylitol 1% gave the highest fluoride ion release (296.90 mg/L) compared to the varnishes with other xylitol concentrations and the positive control. In contrast, PFFV DCPD-xylitol 5% afforded the highest calcium ion release at 111.20 mg/L.ConclusionsThis study concluded that xylitol affects the bioavailability of free fluoride and calcium ions in varnishes. However, the efficacy of fluoride and calcium uptake in enamel and under different in vitro media conditions requires further investigation.     

Fluoride concentration in plaque in adolescents after topical application of different fluoride varnishes

The aim of the study was to measure the fluoride (F) concentration in plaque after a single topical application of different fluoride varnishes with contrasting levels of F. Thirty adolescents (12–17 years) with fixed orthodontic appliances were randomly assigned to one of three groups: Bifluoride (6% F), Duraphat (2.23% F) and Fluor Protector (0.1% F). The varnishes were applied after professional cleaning in one upper quadrant, leaving the opposite quadrant untreated according to the split-mouth technique. Pooled plaque samples from each quadrant were collected at baseline and 3 days, 7 days and 30 days after the varnish treatment, and fluoride was analysed by microdiffusion. All fluoride varnishes increased the fluoride concentration in plaque compared with baseline, and the mean values varied between 23 and 138 ng F/mg after 3 days, depending on varnish F concentration. Compared with the control quadrant, statistically significant elevations were recorded for Bifluoride after 3 days and 7 days and Duraphat after 3 days, while no significant differences were revealed in the Fluor Protector group. The fluoride concentration in plaque was back to baseline levels for all participants in the Duraphat group after 7 days, while some individuals in the Bifluoride and Fluor Protector groups still registered slightly increased levels after 30 days. The results suggest that fluoride varnish treatments resulted in elevated fluoride levels in plaque adjacent to fixed orthodontic appliances for a period of up to 1 week, although different patterns was disclosed for the various brands. Received: 5 October 1999 / Accepted: 18 November 1999     

Enamel fluoride uptake of a novel water-based fluoride varnish

Aim of the in situ-study was to evaluate fluoride retention in sound and demineralised enamel after application of a novel water-based fluoride (0.12% F) varnish Mirafluorid (Hager and Werken, Germany) compared to the resin-based varnish (2.26% F) Duraphat (Colgate, USA). Each five enamel specimens were prepared from 60 bovine incisors. In 150 of these specimens, incipient lesions were produced with acidic hydroxyethylcellulose (pH 4.8; 72 h), 150 specimens were not demineralised. The samples were equally (n=100) allotted to three groups (A: Mirafluord, B: Duraphat, and C: control). Each 80 specimens (40 demineralised and 40 sound) were varnished with either Mirafluorid or Duraphat or remained unfluoridated (controls). The other specimens were used for measuring base-line fluoride content of the respective tooth. Each six specimens (three demineralised and three sound) were fixed in intraoral appliances worn for 5 days by 10 volunteers in three series (A-C). During the experiment, the samples were brushed twice daily with fluoridated toothpaste. KOH-soluble and structurally bound fluoride (0-30 and 31-60 microm depth) was determined immediately, 1, 3 and 5 days after fluoridation. Fluoride uptake was calculated as compared to base-line content and statistically analysed. Immediately after fluoridation, uptake of KOH-soluble and structurally bound fluoride was similar for Mirafluorid and Duraphat in both demineralised and sound enamel. However, at day 1, 3 and 5 statistically significantly higher amounts of KOH-soluble and structurally bound fluoride were found in the samples treated with Duraphat. For Mirafluorid only the uptake for KOH-soluble fluoride and structurally bound fluoride in the first enamel layer (0-30 microm) of the demineralised samples was significantly higher compared to the controls (C). It is concluded that the novel fluoride varnish Mirafluorid deposits less KOH-soluble and structurally bound fluoride on both demineralised and sound enamel compared to Duraphat under in situ-conditions.     

Effects of a sodium fluoride solution and a varnish with different fluoride concentrations on enamel remineralization in vitro

Abstract – To study the efficacy of sodium fluoride varnishes and a NaF solution in remineralization of enamel, 120 slabs of non-carious human enamel enamel were presoftened for 6 h and randomly divided into six groups. The slabs were stored in synthetic saliva for 9 days, except for a daily 30-min immersion in 0.1 M lactic acid-NaOH buffer. During the 9-day period, one group of the slabs received no treatment, and the rest were treated once or three times with 2.3% or 1.1% sodium fluoride varnish Duraphat, or nine times with a 0.1% NaF solution. Finally, the slabs were demineralized for 1 h, and the amount of dissolved Ca and F was determined. Microhardness of enamel was determined initially, after presoftening, after the 9- day period, and after the 1-h demineralization. All fluoride treatments prevented enamel softening almost completely during the 9 days, but the control slabs softened markedly. Fluoride varnishes were more effective than NaF solution. Three applications of 2.3% Duraphat were slightly more effective than any of the other varnish treatments, but one treatment with 2.3% varnish was not more effective than treatments with 1.1% varnish. Enamel treated three times with 1.1% varnish showed the greatest acid resistance during the 1-h demineralization. The results suggest that the efficacy of the varnish was not proportional to the fluoride concentration but rather to the number of applications. Fluoride uptake by enamel was greatest with the most concentrated varnish. Enamel solubility was not, however, directly proportional to the fluoride content of enamel.     

成膜基质对氟化物涂膜抑制釉质早期龋的效果

目的:比较含不同成膜基质的氟化物涂膜抑制釉质早期龋的效果。方法:将制备的90个釉质试样块随机分成6组,分别应用以5种成膜基质(珂巴树脂、渗透型丙烯酸树脂、甲基丙烯酸乙酯共聚树脂、聚合松香、聚乙烯醇缩丁醛)配制的氟涂膜材料和Duraphat氟涂膜进行处理。采用荧光显微镜和显微硬度计测定各组釉质试样块在pH循环前后的荧光值和硬度值的变化;并通过偏光显微镜观察其脱矿深度。结果:pH循环后各组釉质试样块的荧光值和硬度值均较pH循环前明显降低,其中渗透型丙烯酸组与其他组相比,荧光损失率和硬度值变化率最小,与其他各组相比差异均有统计学意义(P<0.05);偏光显微镜观察显示:各组釉质表面均无实质性缺损,渗透型丙烯酸组釉质脱矿深度最浅。结论:氟化物涂膜具有明显的抑制釉质脱矿的作用,含渗透型丙烯酸树脂的氟涂膜效果最好。     

Effects of a sodium fluoride solution and a varnish with different fluoride concentrations on enamel remineralization in vitro

To study the efficacy of sodium fluoride varnishes and a NaF solution in remineralization of enamel, 120 slabs of non-carious human enamel enamel were presoftened for 6 h and randomly divided into six groups. The slabs were stored in synthetic saliva for 9 days, except for a daily 30-min immersion in 0.1 M lactic acid-NaOH buffer. During the 9-day period, one group of the slabs received no treatment, and the rest were treated once or three times with 2.3% or 1.1% sodium fluoride varnish Duraphat, or nine times with a 0.1% NaF solution. Finally, the slabs were demineralized for 1 h, and the amount of dissolved Ca and F was determined. Microhardness of enamel was determined initially, after presoftening, after the 9-day period, and after the 1-h demineralization. All fluoride treatments prevented enamel softening almost completely during the 9 days, but the control slabs softened markedly. Fluoride varnishes were more effective than NaF solution. Three applications of 2.3% Duraphat were slightly more effective than any of the other varnish treatments, but one treatment with 2.3% varnish was not more effective than treatments with 1.1% varnish. Enamel treated three times with 1.1% varnish showed the greatest acid resistance during the 1-h demineralization. The results suggest that the efficacy of the varnish was not proportional to the fluoride concentration but rather to the number of applications. Fluoride uptake by enamel was greatest with the most concentrated varnish. Enamel solubility was not, however, directly proportional to the fluoride content of enamel.     

Studies of fluoride varnishes in Finland.

Despite the artificial fluoridation of drinking water in Kuopio, part of the children have high caries incidence. We therefore started our studies on fluoride varnishes in 1977 in an attempt to find a feasible means of applying fluoride topically in children at high risk of caries. In our first trial, the sodium fluoride varnish Duraphat was found to be effective in preventing caries, but the effectiveness of the silane fluoride varnish Fluor Protector could not be unequivocally established, despite the fact that Fluor Protector deposited markedly more fluoride in enamel than Duraphat. In a second study in children in a low-fluoride area, use of Duraphat was found to be more effective than fortnightly fluoride rinses or Fluor Protector. Increasing the frequency of application from two to four times a year did not increase the effectiveness of Duraphat even in highly caries-prone children in a 2-year trial. On the basis of peak values of fluoride in parotid saliva after application, use of either fluoride varnishes was considered safe. Although the fluoride content of the enamel remained elevated for at least two years after discontinuation of treatment with both varnishes, the caries preventive effect did not continue after the applications were stopped. This shows that increasing the fluoride content of enamel is not the main mechanism by which fluoride varnishes prevent caries, and that the applications need to be continued as long as caries is a problem.     

Fluoride varnishes containing sodium trimetaphosphate reduce enamel demineralization in vitro

Objective: This study evaluated the effects of fluoride varnishes containing sodium trimetaphosphate (TMP) on bovine enamel demineralization in vitro.

Material and methods: Enamel bovine discs were randomly assigned into six groups (n?=?20/group): placebo, 2.5% NaF, 2.5% NaF/5% TMP, 5% NaF, 5% NaF/5% TMP, and a commercial formulation (Duraphat, 5% NaF). Varnishes were applied on all enamel discs and kept for 6?h. Loosely and firmly bound fluoride formed on/in enamel after treatment were analyzed in 10 discs from each group. The other 10 discs were subjected to a pH-cycling regimen for 7 days, and analyzed for surface (SH) and cross-sectional hardness (ΔKHN), as well as for loosely and firmly bound fluoride in/on enamel. Data were analyzed by analysis of variance (ANOVA) followed by Student–Newman–Keuls’ test (p?Results: The lowest SH change and ΔKHN were observed for the 5%NaF/5%TMP varnish, which was significantly different from all the other groups. Both fluoridated varnishes containing TMP promoted significantly lower SH change and ΔKHN when compared with their counterparts without TMP. Loosely and firmly bound fluoride was significantly lower in groups treated with varnishes containing TMP.

Conclusion: TMP and fluoride added to varnishes have a synergistic effect against enamel demineralization in vitro.