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Objectives: This study evaluated the effect of conventional (CD, 1100ppm F) and low-fluoride (LFD, 550ppm F) dentifrices, applied in different quantities, on enamel demineralization, and on fluoride (F) concentrations in the dental biofilm formed in situ., Methods: Five combinations of dentifrices and quantities were tested: placebo (P-F-free) applied on all brush bristles; LFD applied by the transversal technique (0.3g-T1) or on all bristles (0.6g-T2); and CD applied in a pea-sized amount (0.15g-T3) or by the transversal technique (0.3g-T4), in order to produce comparable intensities (F concentration in the dentifrice×amount applied to the brush). Volunteers (n=13, 20-36 years old) wore palatal devices containing 4 bovine enamel blocks, and performed cariogenic challenges (30% sucrose solution) 6×/day, and brushing 3×/day, following a double-blind, cross-over and randomized protocol. On the 8th day, biofilm was collected 5 and 60min after brushing. The percentage of surface hardness loss (%SH), integrated loss of subsurface hardness (ΔKHN) and biofilm F concentrations (solid and fluid phases) were determined. Data were analyzed by repeated-measures ANOVA, Student-Newman-Keuls test, and Pearson's correlation coefficient (p<0.05)., Results: Significantly lower ΔKHN was observed for treatments with higher intensity (T2 and T4) in comparison with the lower intensity (T1 and T3). A strong correlation was observed between ΔKHN and F concentrations in total biofilm (r=-0.71) and biofilm fluid (r=-0.72) 5min after brushing., Conclusions: The treatment intensity has a significant influence on the development of caries lesions in situ., Clinical Significance: The intensity of treatment (amount of dentifrice×concentration) during brushing seems to be a more relevant parameter of clinical efficacy than simply observing the F concentration of the product. The use of a small amount of CD significantly reduced the protective effects against enamel demineralization., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objective: Test the ability of acidic fluoridated solutions to enhance fluoride (F) bound on bacteria (1) and the effect of dentifrice consistency on plaque fluid F uptake (2)., Methods: (1) Streptococcus mutans isolates were grown in BHI medium (37°C/18h). Bacteria were washed either with EDTA or CaCl2 both at 1mM to remove or add calcium, respectively. Pellets were incubated with 12 mM NaF at pH 4.5 or 7 for 1 min and F was quantified in the lysates and supernatants with the electrode, after HMDS-facilitated diffusion. (2) A randomized, double-blind, crossover clinical trial was performed in three phases with nineteen adults (20-35 years) that used one of the dentifrices: commercial toothpaste (1100 ppm F, pH7.0 and conventional viscosity (Sorriso Fresh(®))); experimental liquid dentifrice (ELD) (1100 ppm F, pH7.0 and low viscosity [1.1% carboxymethylcellulose (CMC)]) and ELD (1100 ppm F and high viscosity pH7.0 (2.2% CMC)). F concentration in plaque fluid was analyzed using an inverted F electrode., Results: (1) Significantly higher F amounts were detected in the lysates of bacteria incubated with NaF solution at pH4.5 compared to the supernatant, which was not seen at pH7.0, being this effect calcium-dependent. (2) Significantly higher F concentrations in plaque fluid were found 1h after toothbrushing compared to 12h, but no significant differences were seen among the toothpastes., Conclusions: F at low pH binds more efficiently to S. mutans than at neutral pH and dentifrice viscosity does not interfere in plaque fluid fluoride incorporation., Clinical Significance: pH of the dentifrice but not consistency may be important to F uptake in plaque., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: This in vitro study analysed the effect of different fluoride concentrations in acidic or neutral liquid dentifrices in protecting enamel and dentine from erosive and abrasive wear., Methods: Bovine enamel and dentine specimens (n = 132) were randomly allocated to 11 groups (each n = 12): experimental liquid dentifrices with 550 ppm F, 1100 ppm F, 5000 ppm F or 0 ppm F/placebo (each at pH 4.5 and pH 7.0); and commercial dentifrices with 550 ppm F (Colgate Baby, pH 7.0), 1100 ppm F (Crest, pH 7.0) and 5000 ppm F (Duraphat, pH 7.0). The specimens were subjected to erosion for 90 seconds, 4 times/day, over 7 days. Immediately after the first and last erosion, the specimens were brushed for 15 seconds using one of the dentifrices. Tooth wear was measured profilometrically (μm) and analysed by ANOVA (p < 0.05)., Results: All fluoridated liquid dentifrices significantly reduced enamel wear compared to the placebo and commercial dentifrices. Only liquid dentifrices with 1100 and 5000 ppm F significantly reduced dentine wear compared to placebo dentifrice. The pH had no effect, but the consistency had a significant impact on the effect of dentifrices., Conclusions: Liquid dentifrices with high F concentration appear to be a good option to prevent tooth wear., (© 2013 Australian Dental Association.)

This review discusses the role of matrix metalloproteinases (MMPs) in the development of dentin erosion and the protective effects of MMP inhibitors, based on recent evidence from in vitro and in situ studies. MMPs are present in both dentin and saliva and play an important role in dentin erosion progression. Enzymatic removal of the organic matrix by MMPs increases the demineralization process, since the demineralized organic matrix has been shown to hamper ionic diffusion after an acidic challenge. Recent evidence from in vitro and in situ studies has shown a protective role of MMP inhibitors against dentin erosion and erosion plus abrasion. The inhibitors tested were green tea and its active epigallocatechin-gallate (EGCG), ferrous sulfate, and chlorhexidine. They have been tested in dentifrices, solutions, and gels. The latter led to a more pronounced protective effect against dentin erosion and erosion plus abrasion. The protection was long-lasting and could be observed after up to 10 days of severe erosive and erosive-plus-abrasive challenges in situ. Thus, the use of MMP inhibitors has emerged as an important preventive tool against dentin erosion. Clinical studies should be conducted to confirm the results obtained and to give support to the establishment of clinical protocols of use.

Previous studies have indicated that the use of low-fluoride dentifrices could lead to proportionally higher plaque fluoride levels when compared with conventional dentifrices. This double-blind, randomized, crossover study determined the effects of placebo, low-fluoride, and conventional dentifrices on plaque fluoride concentrations ([F]) in children living in communities with 0.04, 0.72, and 3.36 ppm F in the drinking water. Children used the toothpastes twice daily, for 1 wk. Samples were collected 1 and 12 hrs after the last use of dentifrices and were analyzed for fluoride and calcium. Similar increases were found 1 hr after the children brushed with low-fluoride (ca. 1.9 mmol F/kg) and conventional (ca. 2.4 mmol F/kg) dentifrices in the 0.04- and 0.72-ppm-F communities. Despite the fact that the increases were less pronounced in the 3.36-ppm-F community, our results indicate that the use of a low-fluoride dentifrice promotes a proportionally higher increase in plaque [F] when compared with that achieved with a conventional dentifrice, based on dose-response considerations.

Background: Low-fluoride dentifrices have been suggested as alternatives to reduce dental fluorosis risk, but there is no consensus regarding their clinical effectiveness, which has been suggested to be increased when their pH is acidic., Aims: This single-blind randomized clinical trial evaluated the caries increment during the use of a low-fluoride acidic liquid dentifrice., Methods: Four-year-old schoolchildren (n = 1,402) living in a fluoridated area (0.6-0.8 ppm F) were randomly allocated to 4 groups differing according to the type of dentifrice used over a 20-month period. Group 1 (n = 345): liquid dentifrice, 1,100 ppm F, pH 4.5. Group 2 (n = 343): liquid dentifrice, 1,100 ppm F, pH 7.0. Group 3 (n = 354): liquid dentifrice, 550 ppm F, pH 4.5. Group 4 (n = 360): toothpaste, 1,100 ppm F, pH 7.0. At baseline and after 20 months, clinical examinations were conducted (dmfs index) and caries increment was calculated. Data were analysed by GLM procedure using classrooms (cluster) as unit of analysis (p < 0.05)., Results: The mean ± SD (95% CI) net increments found were as follows. Group 1: 2.06 ± 2.38 (1.8-2.3); group 2: 2.08 ± 2.87 (1.7-2.4); group 3: 2.05 ± 2.79 (1.7-2.4), and group 4: 2.08 ± 2.34 (1.8-2.4). No significant differences were detected among the groups., Conclusion: In a population with high caries risk living in a fluoridated area, as the selected sample, and according to the present protocol, the low-fluoride acidic liquid dentifrice seems to lead to similar caries progression rates as conventional 1,100 ppm F toothpaste., (Copyright © 2010 S. Karger AG, Basel.)

To evaluate the influence of dentifrice pH and fluoride (F) concentration on F uptake by plaque and nails, two sets of 5- to 6-year-old children were randomly allocated into four groups, according to the type of dentifrice they had been using for 1 year: (1) experimental liquid dentifrice (ELD), 1,100 ppm F, pH 7.0; (2) ELD, 1,100 ppm F, pH 4.5; (3) ELD, 550 ppm F, pH 4.5, and (4) commercial toothpaste, 1,100 ppm F, pH 7.0. In one set of children, nails were clipped. In the second, plaque samples were collected 1 h after the last use of dentifrice. F concentration in plaque and nails was analyzed. Plaque F concentration was significantly lower in group 4 than in groups 1-3. Nail F concentration was significantly higher in group 4, and significantly lower in group 3, than in group 1 or 2. Plaque F uptake was influenced significantly by dentifrice consistency and nonsignificantly by pH and F concentration. Reduction of dentifrice pH did not affect nail F concentration., (2009 S. Karger AG, Basel.)

It has been suggested that fluoride retention in plaque is limited by available binding sites. We determined the effects of fluoridated or placebo dentifrices on plaque and salivary fluoride concentrations [F]s in communities with different water fluoride concentrations (0.04, 0.85, 3.5 ppm). After one week of dentifrice use, samples were collected 1.0 and 12 hrs after the last use of dentifrices. After the use of fluoridated dentifrice, plaque fluoride concentrations were higher at both times, except at 12 hrs in the 3.5-ppm community. Plaque concentrations at 1.0 hr after the use of fluoridated dentifrice increased almost constantly (6.5 mmol/kg), but then decreased approximately 50% at 12 hrs in each community. Unlike previous studies, the present findings suggest that the use of fluoridated dentifrice is likely to increase plaque fluoride concentrations significantly for up to 12 hrs in areas where the water contains fluoride close to 1.0 ppm. As previously reported, plaque fluoride concentrations were directly related to calcium concentrations.

This in situ/ex vivo study assessed the effect of different concentrations of fluoride in dentifrices on dentin subjected to erosion or to erosion plus abrasion. Ten volunteers took part in this crossover and double-blind study performed in 3 phases (7 days). They wore acrylic palatal appliances containing 4 bovine dentin blocks divided in two rows: erosion and erosion plus abrasion. The blocks were subjected to erosion by immersion ex vivo in a cola drink (60 s, pH 2.6) 4 times daily. During this step, the volunteers brushed their teeth with one of three dentifrices D (5,000 ppm F, NaF, silica); C (1,100 ppm F, NaF, silica) and placebo (22 ppm F, silica). Then, the respective dentifrice slurry (1:3) was dripped on dentin surfaces. While no further treatment was performed in one row, the other row was brushed using an electric toothbrush for 30 s ex vivo. The appliances were replaced in the mouth and the volunteers rinsed with water. Dentin loss was determined by profilometry and analyzed by 2-way ANOVA/Bonferroni test (a = 0.05). Dentin loss after erosive-abrasive wear was significantly greater than after erosion alone. Wear was significantly higher for the placebo than for the D and C dentifrices, which were not significantly different from each other. It can be concluded that the presence of fluoride concentrations around 1,100 ppm in dentifrices is important to reduce dentin wear by erosion and erosion + abrasion, but the protective effect does not increase with fluoride concentration., ((c) 2008 S. Karger AG, Basel)

This study evaluated the effectiveness of acidic low-fluoride dentifrices compared to conventional neutral dentifrices. Enamel blocks were submitted to pH cycling and treatment with slurries of dentifrices containing 0, 275, 412, 550 and 1,100 microg F/g (pH 4.5 or 7.0), and also a commercial dentifrice (1,100 microg F/g) and a commercial children's dentifrice (500 mug F/g). Variations in surface microhardness and in the mineral content in enamel after pH cycling were calculated. Enamel blocks treated with acidic dentifrices exhibited less mineral loss compared to neutral dentifrices (ANOVA; p < 0.05). The acidic dentifrices with 412 and 550 microg F/g had the same effectiveness as the neutral 1,100-microg F/g dentifrice and commercial 1,100-microg F/g dentifrice., (Copyright 2007 S. Karger AG, Basel.)

This in situ/ex vivo study assessed the effect of fluoride dentifrice on eroded enamel subjected to brushing abrasion. In a crossover study performed in 2 phases, 10 volunteers wore acrylic palatal appliances, each containing 3 human enamel blocks. Dentifrice was used to brush the volunteers' teeth and the specimens subjected to abrasion. In phases A and B the dentifrices used had the same formulation, except for the absence or presence of fluoride, respectively. The blocks were subjected to erosion by immersion of the appliances in a cola drink for 5 min, 4 times a day. Then the blocks were brushed, and the appliance was replaced into the mouth. Enamel alterations were determined using profilometry and percentage change in surface microhardness (%SMHC) tests. The data were tested using the paired t test. The mean wear values (+/-SD, microm) were: group A 6.84 +/- 1.72 and group B 5.38 +/- 1.21 (p = 0.04). The mean %SMHC values (+/-SD) were: group A 54.6 +/- 16.2 and group B 45.7 +/- 6.8 (p = 0.04). Fluoride dentifrice had a protective effect on eroded enamel subjected to brushing abrasion.

This double-blind study assessed the fluoride (F) concentration in whole saliva and F bioavailability after the use of low-F dentifrices with reduced pH. Whole saliva was collected from 10 volunteers after brushing with: experimental dentifrices (pH 5.5) 275, 550 and 1,100 ppm F; commercial 500 ppm F, pH 6.9 and a 'gold standard' 1,100 ppm F, pH 6.5. To analyze F bioavailability, 9 volunteers ingested weights of four dentifrices equivalent to 2 mg F: 1,500 ppm F/MFP/CaCO3, pH 9.5; 1,100 ppm F/NaF/silica, pH 5.5; 1,100 ppm F/NaF/silica, pH 7.0 and 1,100 ppm F/NaF/silica, pH 6.5 ('gold standard'). Ductal saliva and urine were collected. F was analyzed by electrode. Data were tested using ANOVA and Tukey's post hoc test (p < 0.05). The 550 ppm F/pH 5.5 dentifrice was similar to the 'gold standard' in its effect on whole saliva F concentration. The area under the curve of ductal saliva F concentration x time and urinary F excretion rates did not differ among the dentifrices. The results show that acidic low-F dentifrices are effective in increasing salivary F concentration and pH reduction does not seem to affect their F bioavailability., (2007 S. Karger AG, Basel)

The use of fingernails and urine as biomarkers of exposure to fluoride (F) from fluoridated dentifrice and varnish was evaluated in twenty 4- to 7-year-old children, who were divided into two groups: group A (9 caries-free children) and group B (11 children with past caries experience). They used a placebo dentifrice for 28 days, fluoridated dentifrice (1,570 ppm F) for the following 28 days, and placebo dentifrice for an additional 28 days, then returned to their usual dentifrices. Group B children also received 4-week applications of a varnish (2.26% F) while using the fluoridated dentifrice. Urinary collections were performed 24 h before the use of fluoridated dentifrice and 24 h (group A) or 48 h (group B) after. Fingernails were clipped every 2 weeks, for 26 weeks. Total F intake from diet and dentifrice was estimated. Fingernail F concentrations did not vary significantly throughout the study. Twenty-four-hour urinary F outputs (mean +/- SD, microg) were: 414 +/- 200 and 468 +/- 253 for placebo and F dentifrices, respectively (group A) and 402 +/-206, 691 +/- 345, 492 +/- 243 for placebo dentifrice, F dentifrice plus F varnish and F dentifrice, respectively (group B). The use of F dentifrice did not cause a significant increase in the urinary F output. However, when F varnish was used, a transitory increase in the urinary F output was detected (p = 0.001), returning to baseline levels in the last 24 h. Thus, F varnish is a safe method for topical F application even in children that use F dentifrice regularly. According to our protocol, urine was a suitable biomarker of exposure to F from dentifrice plus varnish, but not from dentifrice alone, while nails were not.

The results of a recent study by Whitford et al. [Caries Res 2002;36:256-265] with subjects whose drinking water was fluoridated led to two major conclusions: (1) Compared to the use of a placebo dentifrice, plaque fluoride concentrations ([F]) throughout much of the day are not significantly increased by the use of an F dentifrice but (2) they are positively related to plaque [Ca] (p = 0.0001). The present double-blind, double-crossover study with 16 subjects used the same protocol and was done to: (1) determine the effects of the use of an F dentifrice on salivary and plaque [F] in a community without water fluoridation and (2) further examine the relationship between plaque [Ca] and [F]. Following the use of an F dentifrice or placebo for one week, whole saliva and plaque were collected 1.0 and 12 h after the last use of the products. The study was repeated to include rinsing with a 20 mmol/l CaCl(2) solution immediately before the use of the dentifrices. The CaCl(2) rinse had only minor effects on salivary [Ca] and [F] and none on the plaque concentrations. Unlike the results found in the fluoridated community, all salivary and plaque [F] associated with the use of the F dentifrice were significantly higher than those associated with the use of the placebo. The results suggest that the cariostatic effectiveness of an F dentifrice should be greater in areas without water fluoridation. As noted previously, plaque [F] were positively related to plaque [Ca] (p = 0.0001)., (Copyright (c) 2005 S. Karger AG, Basel.)

This study evaluated in vitro commercial desensitizing toothpastes with respect to the prevention of erosion and explored the effect of their agents alone or in combination with fluoride. Bovine enamel blocks were randomly allocated to five groups of 20 and exposed to: Sensodyne ProNamel (1,425 ppm F as NaF, 5% KNO3), Sensodyne Original (no fluoride, 10% SrCl2), Colgate Sensitive (1,450 ppm F as sodium monofluorophosphate, 5% K citrate), Crest (fluoride-only toothpaste, 1,100 ppm F as NaF) and water (negative control). A second experiment was conducted with experimental dentifrices containing fluoride (NaF, 1,100 ppm F), 10% SrCl2, 5% KNO3 or 5% K citrate alone or the latter three combined with F. The samples were submitted to four cycles, alternating demineralization (cola, 10 min) and remineralization (artificial saliva, 1 h). Before and between cyclic de- and remineralization, blocks were treated with slurries of the respective toothpastes or water (1 min). Erosive tissue loss was analyzed by profilometry. Data were analyzed by Kruskal-Wallis and Dunn’s tests (p < 0.05). The mean erosion depth (± SE, μm) was significantly less for Colgate Sensitive (0.04 ± 0.00), Sensodyne Original (0.06 ± 0.01) and Crest (0.07 ± 0.01) than for Sensodyne ProNamel (2.36 ± 0.25) or water (2.92 ± 0.24), which did not significantly differ from each other. Both F and the desensitizing agents alone reduced erosion, but no additive effect was found. In addition, the combination of F and KNO3 did not reduce erosion. These in vitro results suggest that the presence of fluoride or desensitizing substances in toothpastes, alone or in combination, can reduce erosion of enamel, but this is not valid for all the formulations. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

This blind and randomized-controlled trial analysed chlorhexidine dentifrices in relation to dental plaque, gingivitis, bleeding, calculus and enamel extrinsic staining development. Volunteers in fixed orthodontic therapy used the following dentifrices: 1100 ppmF, NaF (group A, n=27); experimental, 1100 ppmF, NaF and chlorhexidine 0.95% (group B, n=28); and experimental, chlorhexidine 0.95% (group C, n=28). At baseline, after 6, 12 and 24 weeks, clinical examinations were carried out. The gingivitis, bleeding and plaque data were tested byanova and Tukey's post hoc tests. Stain and calculus data were analysed by Kruskal–Wallis and Dunn's post hoc tests ( p<0.05). Plaque, gingivitis and bleeding scores improved in all three groups, but up to the 6 and 12 weeks examination the products containing chlorhexidine were statistically better. The chlorhexidine dentifrices significantly increased the mean of the stain index, although most of the patients did not notice the stains. The calculus index was not significantly modified. In summary, this study suggests that the use of dentifrices containing chlorhexidine seems to be effective for the treatment of gingivitis in orthodontic patients, although the intense motivating contact that the volunteers had with the researchers may have also played a role. [ABSTRACT FROM AUTHOR]

Fluoride toothpastes are a risk factor for the development of dental fluorosis. Products with low fluoride content offer a higher security, but their effectiveness must be proven. The aim of this in vitro study was to compare two acidified toothpastes with low fluoride concentration (412 and 550 μg F/g) with neutral toothpastes. Bovine enamel blocks were selected by surface microhardness (SMH) and randomized to twelve groups of 13, according to the fluoride concentration in toothpaste (placebo, 275, 412, 550 or 1,100 μg F/g) and pH (7.0 or 5.5). Two commercially available toothpastes were also studied: a 1,100-μg F/g, pH 7.0 paste (positive control) and a children’s paste (500 μg F/g, pH 7.0). The blocks were subjected to pH cycling for 7 days. The toothpaste treatment was done twice daily. Surface and cross-sectional microhardnesses were assessed to calculate the percentage change of SMH (%SMH) and the mineral loss (ΔZ). The amount of fluoride, calcium and phosphorus in the solutions after the pH cycling was also analyzed. Compared to neutral toothpastes, the acidified toothpastes reduced the %SMH in all F concentrations. Higher F and lower Ca and P concentrations were found in solutions for the acidified toothpastes. Regarding ΔZ, only the positive control, 1,100-μg F/g (acidified and neutral) groups were not statistically different. The acidified toothpastes showed a dose-response relationship with all variables. For the low-fluoride toothpastes evaluated, only the 550-μg F/g acidified paste had the same anticariogenic action as the 1,100-μg F/g neutral paste. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]