Effect of rinsing with water immediately after APF gel application on enamel demineralization in situ

This double-blind crossover in situ study evaluated the effect of rinsing with water immediately after the application of acidulated phosphate fluoride (APF) on enamel demineralization. APF application was followed by: no rinsing or consuming of liquids or solids for the next 30 min; immediately washing with water jet or drinking of a glass of water. All treatments showed a statistically significant decrease in enamel mineral loss compared to the control (p < 0.05), but the differences among treatments were not significant (p > 0.05). The data suggest that the recommendation of asking patients to refrain from drinking water following professional APF application does not seem to have an influence on the anticaries effect of fluoride.     

APF and dentifrice effect on root dentin demineralization and biofilm

Because dentin is more caries-susceptible than enamel, its demineralization may be more influenced by additional fluoride (F). We hypothesized that a combination of professional F, applied as acidulated phosphate F (APF), and use of 1100-ppm-F dentifrice would provide additional protection for dentin compared with 1100-ppm-F alone. Twelve adult volunteers wore palatal appliances containing root dentin slabs, which were subjected, during 4 experimental phases of 7 days each, to biofilm accumulation and sucrose exposure 8x/day. The volunteers were randomly assigned to the following treatments: placebo dentifrice (PD), 1100-ppm-F dentifrice (FD), APF + PD, and APF+FD. APF gel (1.23% F) was applied to the slabs once at the beginning of the experimental phase, and the dentifrices were used 3x/day. APF and FD increased F concentration in biofilm fluid and reduced root dentin demineralization, presenting an additive effect. Analysis of the data suggests that the combination of APF gel application and daily regular use of 1100-ppm-F dentifrice may provide additional protection against root caries compared with the dentifrice alone.     

Effect of a calcium carbonate-based dentifrice on enamel demineralization in situ

Since the effect of calcium carbonate (CaCO(3)) based dentifrice on enamel demineralization is not clearly established, it was evaluated using the IEDT model described by Zero's group in 1992. This study had a crossover design and 10 volunteers were submitted to 3 treatment groups: a negative control, brushing without dentifrice; an active control, brushing with silica-based dentifrice (SiO(2)/MFP group), and the experimental group, brushing with CaCO(3)-based dentifrice (CaCO(3)/MFP). Both dentifrices contained 1,500 microgram F/g (w/w) as sodium monofluorophosphate (MFP). Enamel surface microhardness was determined in the dental blocks and the percentage change in relation to baseline was calculated. Fluoride uptake in enamel and its concentration in 'test plaque' were determined. The results showed that the dentifrice containing CaCO(3)/MFP was more effective than SiO(2)/MFP in reducing enamel demineralization (p < 0.05). A higher concentration of fluoride ion was found in 'test plaque' treated with CaCO(3)/MFP than in the negative control (p < 0.05). The results suggest that CaCO(3) abrasive may enhance the effect of fluoride present in dentifrice on dental caries control.     

Effect of high-fluoride dentifrice and bracket bonding composite material on enamel demineralization in situ

Clinical Oral Investigations - This in situ study evaluated the effect of high-fluoride dentifrice (5000&nbsp;μg&nbsp;F−/g) and fluoride-containing bonding composite resin on...     

Effect of frequency of sucrose exposure on dental biofilm composition and enamel demineralization in the presence of fluoride

It has been suggested that enamel would resist higher frequencies of sucrose exposure if fluoride from water or dentifrice is being used. However, the effect of increasing frequencies of sugar on dental biofilm composition is not well known. Ten volunteers living in a fluoridated area wore palatal appliances bearing human enamel slabs during 14 days. The slabs were exposed to 20% sucrose solution 0 (control), 2, 4, 6, 8 or 10 times/day and the volunteers used fluoride dentifrice 3 times/day. Enamel demineralization was significantly greater than control for sucrose frequencies higher than 6 times/day. However, biofilm mass, total microbiota, total streptococci, lactobacilli counts and insoluble extracellular polysaccharide concentration increased, while Ca, P(i) and F concentration in whole biofilm decreased significantly, with frequencies of sucrose exposure lower than 6 times/day. The findings confirm that fluoride can reduce enamel demineralization if sucrose consumption is not higher than 6 times/day, but changes in the biochemical and microbiological composition of the biofilm are observed with lower frequencies of sucrose use.     

Effect of sucrose concentration on dental biofilm formed in situ and on enamel demineralization

The relationship between sucrose concentration and cariogenic potential was studied in situ. Adult volunteers wore intraoral palatal appliances containing human dental enamel blocks, which were extraorally submitted 8 times a day for 14 days, to the treatments: deionized distilled water and sucrose solutions from 1 to 40%. The biofilm formed was analyzed with respect to acidogenicity and biochemical composition; enamel demineralization was evaluated by microhardness. The results showed that 1% sucrose is less cariogenic than 5% or higher concentrations, although sucrose solution at 40% was still able to increase the concentration of insoluble polysaccharide in the biofilm formed. The findings suggest that the threshold of sucrose solution concentration for the formation of a cariogenic biofilm is 5%, which provided the same cariogenic potential as that observed for 10 and 20% sucrose solution.     

Effect of sucrose containing iron (II) on dental biofilm and enamel demineralization in situ

Since the effect of iron (Fe) on the cariogenicity of sucrose in humans is unexplored, this study assessed in situ the effect of Fe co-crystallized with sucrose (Fe-sucrose) topically applied in vitro on the acidogenicity, biochemical and microbiological composition of the dental biofilm formed in vivo and on the demineralization of the enamel. During two phases of 14 days each, 16 volunteers wore palatal appliances containing blocks of human enamel, which were submitted to four groups of separate treatments: (1) water; (2) 20% sucrose; (3) 20% (w/v) sucrose plus 18 microg Fe/ml, and (4) 20% (w/v) sucrose plus 70 microg Fe/ml. The solutions were dripped onto the blocks 8 times per day. The biofilms formed on the blocks were analyzed with respect to acidogenicity, biochemical and microbiological composition. Mineral loss was determined on enamel by surface and cross-sectional microhardness. Lower demineralization was found in the blocks subjected to Fe-sucrose (70 microg Fe/ml) than in those treated with sucrose (p < 0.05). This concentration of Fe also reduced significantly the populations of mutans streptococci in the biofilm formed on the blocks. In conclusion, our data suggest that Fe may reduce in situ the cariogenic potential of sucrose and the effect seems to be related to the reduction in the populations of mutans streptococci in the dental biofilm formed.     

In situ effect of sodium fluoride or titanium tetrafluoride varnish and solution on carious demineralization of enamel

This study evaluated the effect of titanium tetrafluoride (TiF(4)) formulations on enamel carious demineralization in situ. Thirteen subjects took part in this cross-over, split-mouth, double-blind study performed in three phases of 14 d each. In each subject, two sound and two predemineralized specimens of bovine enamel were worn intra-orally and plaque accumulation was allowed. One sound and one predemineralized specimen in each subject was treated once with sodium fluoride (NaF) varnish or solution (Treatment A); TiF(4) varnish or solution (Treatment B); or placebo varnish or no treatment (Treatment C). The initially sound enamel specimens were exposed to severe cariogenic challenge (20% sucrose, eight times daily for 5 min each time), whereas the predemineralized specimens were not. Eleven subjects were able to finish all experimental phases. The enamel alterations were quantified by surface hardness and transversal microradiography. Demineralization of previously sound enamel was reduced by all test formulations except for the NaF solution, while both TiF(4) formulations were as effective as NaF varnish. For the predemineralized specimens, enamel surface hardness was increased only by TiF(4) formulations, while subsurface mineral remineralization could not be seen in any group. Within the experimental protocol, TiF(4) was able to decrease enamel demineralization to a similar degree as NaF varnish under severe cariogenic challenges, while only TiF(4) formulations remineralized the enamel surface.     

Low‐fluoride toothpaste and deciduous enamel demineralization under biofilm accumulation and sucrose exposure

Cury JA, do Amaral RC, Tenuta LMA, Del Bel Cury AA, Tabchoury CPM. Low‐fluoride toothpaste and deciduous enamel demineralization under biofilm accumulation and sucrose exposure. Eur J Oral Sci 2010; 118: 370–375. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci Because low‐fluoride toothpaste (500 p.p.m. F) has not clearly been shown to be effective for controlling caries in caries‐active children, this experimental in situ study was conducted to evaluate whether its effect, when compared with a conventional toothpaste (1,000–1,500 p.p.m. F), would depend on the cariogenic challenge. During four phases of 14 d each, 14 volunteers used 500 or 1,100 p.p.m. F toothpaste and wore palatal appliances containing deciduous enamel slabs, on which biofilm was accumulated and exposed to 20% sucrose solution at frequencies increasing from two to eight times per day. The F concentration was determined in the biofilm formed, and enamel demineralization was assessed by surface hardness loss (%SHL) and integrated area of hardness × lesion depth (ΔS). The F uptake by enamel was also determined. Fluoride in biofilm fluid and solids was statistically higher when conventional F toothpaste was used. The toothpastes did not differ statistically in terms of %SHL, ΔS, and F in enamel, but only the conventional F toothpaste significantly reduced caries‐lesion progression according to the frequency of sucrose exposure. The findings suggest that the high‐F availability in biofilm, resulting from the use of conventional toothpaste compared with low‐F toothpaste, may be important for reducing caries‐lesion progression in conjunction with a high frequency of sucrose exposure.     

In situ study of sucrose exposure, mutans streptococci in dental plaque and dental caries.

The purpose of this study was to investigate the relationship among frequency of sucrose exposure, mutans streptococci levels and dental caries. Adult volunteers took part in this crossover study performed in 4 phases of 28 days each. The volunteers wore intra-oral palatal appliances containing blocks of human dental enamel and dripped 20% sucrose solution onto the dental blocks from 0 to 8 times/day. After each phase, the colony forming units (CFU) were determined in dental plaque and enamel dental caries was evaluated using cross-sectional hardness. Sucrose frequency had no statistically significant effect on mutans streptococci levels. In the enamel cross-sectional hardness tests, significant differences (p < 0.05) in relation to area of mineral loss were observed only when sucrose exposure was 8 times/day. Similar results were obtained when cross-sectional hardness was assessed at each distance from enamel surface.     

In situ effect of a dentifrice with low fluoride concentration and low pH on enamel remineralization and fluoride uptake

Since the anticaries effect of a dentifrice with low fluoride concentration and low pH is unknown, the aim of the present study was to evaluate in situ the enamel remineralizing ability of this type of formulation. A double-blind crossover design employing 3 phases of 45 days was conducted. Six adult volunteers wore palatal devices containing 6 previously demineralized human dental enamel slabs, which were subjected 3 times a day to one of the following treatments: non-fluoridated dentifrice (negative control); dentifrice containing 1, 100 microg F/g, pH 7.0 (positive control); dentifrice containing 550 microg F/g, pH 5.5 (experimental). At the end of each phase, enamel remineralization was assessed in terms of cross-sectional microhardness, and loosely as well as firmly bound fluoride formation was determined on the enamel surface. Fluoridated dentifrices were more effective than the negative control in forming loosely and firmly bound fluoride on enamel (P < 0.05). However, the positive control formed more loosely bound fluoride than the other treatments (P < 0.05). Microhardness analysis showed that the fluoridated dentifrices were more effective than the negative control (P < 0.05) in remineralizing dental enamel, although no statistically significant difference was observed between them. Thus, the experimental dentifrice was shown to be effective in remineralizing dental enamel, and this may be attributable to its ability to form firmly bound fluoride on enamel.     

Effect of dentifrice containing fluoride and/or baking soda on enamel demineralization/remineralization: an in situ study

The additive effect of baking soda on the anticariogenic effect of fluoride dentifrice is not well established. To evaluate it, a crossover in situ study was done in three phases of 28 days. Volunteers, using acrylic palatal appliances containing four human enamel blocks, two sound (to evaluate demineralization) and two with artificial caries lesions (to evaluate remineralization), took part in this study. During each phase, 10% sucrose solution was dripped (3 times a day) only onto the sound blocks. After 10 min, a slurry of placebo, fluoride (F) or fluoride and baking soda (F+NaHCO(3)) dentifrice was dripped onto all enamel blocks. The results showed a higher F concentration in dental plaque formed during treatment with F+NaHCO(3) than placebo (p<0.05), but the difference related to F dentifrice was not significant. The enamel demineralization was lower, and remineralization was greater, after treatment with F+NaHCO(3) than placebo (p<0.05), but the difference related to F dentifrice was not significant. The data suggest that baking soda neither improves nor impairs the effect of F dentifrice on reduction of demineralization and enhancement of remineralization of enamel.     

Influence of extraoral xylitol and sucrose dippings on enamel demineralization in vivo

This paper describes the effect of xylitol on demineralized enamel in plaque-free and plaque-covered conditions in vivo. Fissure-like plaque retention grooves were created in 66 human enamel blocks and demineralized in vitro. The blocks were mounted in a prosthesis of 11 participants, who used a 2.5% xylitol, a 2.5% sucrose solution or water extraorally in a randomized cross-over design, for three periods of 16 days. The participants submerged the prosthesis twice a day in the solution during 5 min. Mineral loss and lesion depth were measured before and after the in vivo experiment, using quantitative microradiography and polarized light microscopy. Lesion depth at the surface enamel was +/- 45 microns, at the wall of the grooves +/- 30 microns and at the bottom of the grooves +/- 50 microns before the experiment. After 16 days the lesion depth at the wall of the grooves was +/- 40 microns and at the bottom of the grooves +/- 75 microns. In the grooves no differences were found between the xylitol, the sucrose and the water treatment. At the surface enamel a significant reduction of enamel demineralization was found after the xylitol dippings. The lesion depth at the surface enamel increased 17 microns after the sucrose treatment and 7 microns after the xylitol treatment. The mineral loss after the sucrose and the water treatment were both approximately three times higher than the mineral loss after the xylitol treatment.     

Effects of fluoride- and chlorhexidine-containing varnishes on plaque composition and on demineralization of dentinal grooves in situ

The aim of the study was to compare the effects of Cervitec, containing 1% chlorhexidine (CHX) and 1% thymol, Fluor Protector, containing 0.1% fluoride, their 1:1 mixture, and a placebo varnish on the percentage of mutans streptococci and lactobacilli in plaque and on the underlying dentin demineralization, as assessed by microradiography. Bovine dentine discs, fitted with three parallel grooves, received one of the varnish treatments into the first groove and on the adjacent part of the dentin surface. Volunteers (n = 23) wore the discs fixed to their partial dentures for four consecutive 3 wk periods. Microbiological analysis of plaque accumulated in the grooves showed no difference between groups. Fluoride varnishes (Fluor Protector and mixed varnish) had a significantly larger inhibitory effect on mineral loss in the treated groove than Cervitec or placebo. All treatment varnishes had more pronounced effect in panelists (n = 14) with higher degree of demineralization (mineral loss in placebo group > or = 1,200 vol% x microm). In these panelists, CHX-containing varnishes showed an inhibitory effect on demineralization in all grooves, also in the two non-varnished grooves. As fluoride varnishes had the largest localized effect on demineralization, and CHX varnishes were showing a peripheral effect, a combined treatment could be the preferred method to obtain an optimal caries preventive effect in caries-prone individuals.     

Rate and mechanism of enamel demineralization in situ.

In this paper, data are presented on the in situ demineralization of human enamel as a function of the demineralization period. To quantify the mineral loss parameters versus time, it is important to obtain information on the kinetics, and thus on the mechanism of dental caries. The results show that for in situ enamel demineralization, the lesion depth as well as the mineral loss parameter both vary linearly with the demineralization time. This is in contrast to in vitro lesion formation where the third power, or the square power of the lesion depth is linearly related to the demineralization time. In in situ demineralization, the rate-determining step of the demineralization process is the inhibitor-controlled dissolution process at the enamel crystallite surfaces, while the inhibitor content (F-, proteins etc.) in the lesion originating from the plaque, saliva and enamel is high. Furthermore, the study indicates that in in situ demineralization, interprismatic mineral loss is very important.     

The intra-oral effect on enamel demineralization of extracellular matrix material synthesized from sucrose by Streptococcus mutans

The role of extracellular matrix material (EMM) synthesized from sucrose (S) by Streptococcus mutans IB-1600 in altering the demineralizing potential of artificial plaque was evaluated with an intraoral enamel demineralization test (IEDT). The artificial plaque samples were prepared from cells cultivated in Todd-Hewitt broth (THB) supplemented with various S concentrations and by mixing THB-grown cells with increasing proportions of EMM (heat-killed THB + 2% S-cultivated cells). The samples were also evaluated for cell density (DNA content) and acidogenicity in vitro (pH-stat), as well as for in situ pH changes during a 45-minute intra-oral test following a 10% glucose rinse. An increase in the proportion of EMM relative to cell density was associated with an increase in enamel demineralization. This trend reversed when the ratio of cells to EMM was less than 1:19. Experiments involving strains of S. mitis, S. sanguis, and S. salivarius suggested a similar effect of EMM. The intra-oral pH data suggest that the presence of EMM may enhance demineralization by altering diffusion properties of plaque.     

Effect of a calcium carbonate-based dentifrice on in situ enamel remineralization

This crossover study evaluated the effect of calcium carbonate (CaCO(3))-based monofluorophosphate dentifrice on enamel remineralization. Ten volunteers wore palatal appliances containing four enamel blocks with caries-like lesions, two of them covered by a test plaque of mutans streptococci. The following treatments were evaluated: a negative control, a silica-based or a CaCO(3)-based dentifrice, and the percentage of enamel surface microhardness recovery was determined. The CaCO(3)-based dentifrice was more effective than the negative control on the enhancement of enamel remineralization, either in the presence or absence of test plaque. This efficacy was also shown by the silica-based dentifrice but only in the presence of test plaque.     

酪蛋白磷酸肽钙磷复合体治疗正畸后釉质脱矿的临床研究

目的研究酪蛋白磷酸肽钙磷复合体(CPP-ACP)对正畸后釉质脱矿的治疗作用。方法选择63例正畸治疗结束后,上牙(14~24,或15~25)唇面釉质存在轻度到中度脱矿的患者,随机分为2组:试验组31例,对照组32例。两组均给予含0.14%氟牙膏刷牙,每天晚上刷牙结束后试验组在脱矿牙牙面应用含有CPP-ACP的GC护牙素,对照组应用除不含CPP-ACP成分外,其他成分相同的安慰剂糊剂。临床检测指标为牙釉质脱矿指数(EDI)。观察时间为正畸结束当天,治疗1、3个月后,采用STATA12.0软件包对数据进行单因素方差分析。结果 58例完成试验(试验组28例,对照组30例),两组EDI总和均较治疗前降低。治疗前,治疗1个月后3个月后试验组的EDI分别为(0.5903±0.2585),(0.4514±0.2077),(0.2396±0.1499);对照组为(0.5291±0.2494),(0.4397±0.2068),(0.3287±0.1757)。治疗前和治疗1个月后两组EDI的差异无统计学意义,治疗3个月后试验组EDI少于对照组,差异有统计学意义。结论可以通过使用含CPP-ACP的GC护牙素来治疗正畸后釉质脱矿。     

Effect of dentifrice containing fTCP,CPP-ACP and fluoride in the prevention of enamel demineralization

Objective: To evaluate the effect of different fluoride- and calcium- and/or phosphate-containing products on their ability to prevent enamel demineralization under pH cycling conditions.

Material and methods: Enamel bovine specimens were assigned to the following groups: G1-MPP (MI Paste Plus, 0.2% NaF, Recaldent?, GC Corporation Tokyo, Japan); G2-FD (Crest? Cavity Protection, 0.243% NaF, Procter &; Gamble, USA); G3-CLP (Clinpro? 5000, 1.1% NaF, 3M ESPE, USA); and G4-CO (Control without fluoride, Silica-based dentifrice; Daudt Ltda, Brazil). The specimens were soaked in demineralizing solution for 6?h and remineralizing solution for 18?h alternatively for 10 days. The toothpaste was prepared with deionized water in a 1:3 ratio (w/v) for three minutes daily. The solutions were renewed every 48?h. After cycling, enamel changes were analysed by percentage change of SMH (%SMH) and energy-dispersive X-ray spectroscopy (EDS). The %SMH value observed for G3-CLP (2.9?±?39.2) was higher than that found in G4-CO (?13.0?±?20.7), G1-MPP (?8.9?±?20.9) and G2-FD (?3.9?±?27.1). The %SMH was similar for all treatment groups (one-way ANOVA and Tukey’s HSD; p?2+ and P_total in the remineralization solutions were not different among all groups (Kruskal–Wallis; p?2+ concentration in the demineralization solution was significantly lower in G1-MPP. Ca²⁺ concentration increased in all groups after 48?h, except for G3-CLP. The EDX quantitative analysis showed that the atomic % of elements is lower level at G4-CO.

Conclusions: The Clinpro? 5000 demonstrated having the most protective effect against demineralization; however, the % SMH was similar for all groups.