The effects of low-fluoride toothpaste supplemented with calcium glycerophosphate on enamel demineralization

Objectives

The aim of the present study was to evaluate the effects of different concentrations of calcium glycerophosphate (CaGP) in toothpastes with low-fluoride (low-F) concentrations on enamel demineralization by using a bovine enamel and pH cycling model.

Materials and methods

Experimental toothpastes containing 0 or 500 μg F/g (NaF) and CaGP concentrations of 0, 0.1, 0.25, 0.5, 1, and 2 % were manufactured. A commercial toothpaste was used as a positive control (1,100 μg F/g). After polishing and hardness tests, enamel blocks were subjected to pH cycling for 5 days and toothpaste treatment twice daily. The treatment regimen involved soaking all blocks in the corresponding slurry for 1 min (2 ml/block). Surface and cross-sectional hardness and fluoride concentrations in enamel were analyzed. The hardness data were analyzed using a one-way ANOVA followed by a Bonferroni post hoc test. Fluoride concentrations were analyzed using a Kruskal–Wallis followed by a Student–Newman–Keuls post hoc test.

Results

The mineral loss with the toothpaste containing 500 μg F/g and 0.25 % CaGP was lower than that in the other groups (p?<?0.05). Fluoride concentrations in the enamel treated with 0.1, 0.25, and 0.5 % CaGP toothpastes were similar to those in the enamel treated with the 500 μg F/g toothpaste (p?>?0.05). A greater concentration of CaGP reduced the fluoride levels in enamel (p?<?0.05).

Conclusions

The results from the present in vitro study show that a low-F (500 μg F/g) toothpaste is capable of maintaining the efficacy of 1,100 μg F/g toothpaste when supplemented with 0.25 % of CaGP.

Clinical relevance

The developed toothpaste prevents caries as a standard one and is safe for individuals of any age group.     

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.     

Effect of low-fluoride toothpastes combined with hexametaphosphate on in vitro enamel demineralization

Objectives

The aim of this study was to evaluate the anticaries effect of low-fluoride toothpastes combined with hexametaphosphate (HMP) on enamel demineralization.

Methods

Bovine enamel blocks were subjected to pH cycling and treatment with toothpaste's slurries (15 groups; 2×/day). Toothpaste mixtures contained the following: no fluoride (F) plus HMP (from 0 to 3.0%); 250 ppm F plus HMP (from 0 to 3.0%); 500 ppm F; 1100 ppm F; and a commercial toothpaste (1100 ppm F). After pH cycling, surface and cross-sectional hardness, as well as F present in the enamel were determined. The demineralization depth was analyzed using polarized light microscopy. The variables were subjected to 1-way ANOVA, followed by Student–Newman–Keuls’ test (p < 0.05).

Results

In the absence of fluoride, 0.5% HMP promoted the lowest mineral loss and its effect was similar to that of a 250 ppm F toothpaste (p > 0.05). The combination of 0.5% HMP and 250 ppm F resulted in lower mineral loss (p < 0.05) and similar lesion depth when compared to the 1100 ppm F toothpaste (p > 0.05).

Conclusion

To conclude, the combination of 0.5% HMP and 250 ppm fluoride in a toothpaste has a similar inhibitory effect on enamel demineralization in vitro when compared to a toothpaste containing 1100 ppm F.

Clinical significance

The anticaries effect of toothpaste containing 250 ppm F combined with 0.5% HMP was similar to that of a 1100 ppm F toothpaste, despite the 4-fold difference in F concentration. Although such effects still need to be demonstrated in clinical studies, it may be a viable alternative for preschool children.     

In vitro evaluation of acidified toothpastes with low fluoride content

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 microg 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 microg F/g) and pH (7.0 or 5.5). Two commercially available toothpastes were also studied: a 1,100-microg F/g, pH 7.0 paste (positive control) and a children's paste (500 microg 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 (DeltaZ). 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 DeltaZ, only the positive control, 1,100-microg 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-microg F/g acidified paste had the same anticariogenic action as the 1,100-microg F/g neutral paste.     

pH-cycling models to evaluate the effect of low fluoride dentifrice on enamel de- and remineralization

Since the currently available pH-cycling models do not differentiate the anti-caries potential of dentifrices with low fluoride (F) concentration, two models were developed and tested in the present. Bovine enamel blocks were subjected to the models and treated with F solutions containing from 70 to 280 mug F/mL in order to validate them in terms of dose-response effect. The models were also tested by evaluating the dentifrices Colgate Baby (500 mug F/g, as a low fluoride dentifrice), Tandy (1,100 mug F/g, as an active F-dentifrice) and Crest (1,100 mug F/g, as positive control). Enamel mineral loss or gain was assessed by surface and cross-sectional microhardness, and lesion depth was analyzed by polarized light microscopy. The pH-cycling models showed F dose-response effect either reducing enamel demineralization or enhancing remineralization. The low F dentifrice presented anti-caries potential, but it was not equivalent to the dentifrices containing 1,100 mug F/g. These data suggest that the models developed in this study were able to evaluate the anti-caries potential of low F dentifrice either on resistance to demineralization or on enhancement of remineralization.     

Evaluation of the anticaries benefit of fluoride toothpastes using an enamel insert model

The remineralization potential of fluoride toothpastes was studied using an in situ enamel insert model. Matched blocks of artificially demineralized human enamel were attached to partial dentures of 16 adult volunteers who brushed their teeth with either a toothpaste containing 1,500 ppm F or one containing 2,500 ppm F for a period of 6 weeks in a balanced, randomized crossover experiment. Computerized image analysis of microradiographs was used to measure the mineral density distribution in the enamel before and after in situ treatment. Both toothpastes demonstrated remineralization of artificial carious lesions. Significantly more remineralization was observed in enamel samples treated with the toothpaste containing 2,500 ppm F compared to that containing 1500 ppm F. This result is consistent with the outcome of a recent caries clinical trial testing the same toothpastes and finding enhanced anticaries efficacy from the higher fluoride level.     

Acquisition of alkali-soluble fluoride by enamel through treatment with NaF-containing toothpastes in vitro.

The first aim of the present study was to examine if alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) forms when a NaF-containing toothpaste is applied on human enamel surface in vitro. The centrifuged supernatants of toothpastes dissolved in distilled water were used and four different commercial NaF-containing toothpastes were tested. The second aim was to investigate if pyrophosphate would interfere with the deposition of alkali soluble fluoride. The formation of alkali-soluble fluoride was determined by chemical analysis and visualized by scanning electron microscopy (SEM). It was ascertained that all tested toothpastes contained free fluoride according to the manufacturers' specifications. It was shown that they promoted deposition of alkali soluble fluoride on the enamel surface. The amount of deposited material increased with the time of exposure. The clinical effect of a NaF-containing toothpaste may thus well depend on an initial formation of alkali-soluble fluoride. Fluoride from this reservoir may adsorb onto the enamel crystals and inhibit further demineralization or increase the rate of remineralization during cariogenic challenges. It was also demonstrated that pyrophosphate did not interfere with the deposition of alkali soluble fluoride.     

In vitro acid decalcification of human surface enamel pretreated with toothpaste slurries

An in vitro caries-like challenge of human tooth enamel treated with inorganic fluoride (NaF) and organic fluoride (aliphatic and aromatic amine fluorides) toothpaste slurries has been investigated. The results revealed that the organic fluoride-containing toothpastes affected positively the resistance of tooth enamel to demineralization.     

Effect of fluoride toothpaste with nano-sized trimetaphosphate on enamel demineralization: An in vitro study

ObjectiveThis study evaluated the effect of toothpastes containing 1100 ppm F associated or not with micrometric or nano-sized sodium trimetaphosphate (TMP) on enamel demineralization in vitro, using a pH cycling model.DesignBovine enamel blocks (4 mm × 4 mm, n = 96) were randomly allocated into eight groups (n = 12), according to the test toothpastes: Placebo (without fluoride or TMP); 1100 ppm F (1100F); 1100F plus micrometric TMP at concentrations of 1%, 3% or 6%; and 1100F plus nanosized TMP at 1%, 3% or 6%. Blocks were treated 2×/day with slurries of toothpastes and submitted to a pH cycling regimen for five days. Next, final surface hardness (SHf), integrated hardness loss (IHL), differential profile of integrated hardness loss (ΔIHL) and enamel fluoride (F) concentrations were determined. Data were analyzed by ANOVA and Student-Newman-Keuls’ test (p < 0.05).ResultsThe use of 1100F/3%TMPnano led to SHf 30% higher (p < 0.001) and IHL ∼ 80% lower (p < 0.001) when compared to 1100F. This toothpaste also resulted in ∼64% reduction of mineral loss (ΔIHL) when compared to 1100F. Moreover, the addition of nano-sized TMP promoted increases in enamel F uptake of 90%, 160% and 100%, respectively for the concentrations of 1%, 3% and 6%, when compared to 1100F (p < 0.001).ConclusionThe addition of nano-sized TMP at 3% to a conventional toothpaste significantly decreased enamel demineralization when compared to its counterparts without TMP or supplemented with micrometric TMP.     

Acquisition of alkali-soluble fluoride by enamel through treatment with NaF-containing toothpastes in vitro

The first aim of the present study was to examine if alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) forms when a NaF-containing toothpaste is applied on human enamel surface in vitro. The centrifuged supernatants of toothpastes dissolved in distilled water were used and four different commercial NaF-containing toothpastes were tested. The second aim was to investigate if pyrophosphate would interfere with the deposition of alkali soluble fluoride. The formation of alkali-soluble fluoride was determined by chemical analysis and visualized by scanning electron microscopy (SEM). It was ascertained that all tested toothpastes contained free fluoride according to the manufacturers' specifications. It was shown that they promoted deposition of alkali soluble fluoride on the enamel surface. The amount of deposited material increased with the time of exposure. The clinical effect of a NaF-containing toothpaste may thus well depend on an initial formation of alkali-soluble fluoride. Fluoride from this reservoir may adsorb onto the enamel crystals and inhibit further demineralization or increase the rate of remineralization during cariogenic challenges. It was also demonstrated that pyrophosphate did not interfere with the deposition of alkali soluble fluoride.     

Systematic review of studies comparing the anti-caries efficacy of children's toothpaste containing 600 ppm of fluoride or less with high fluoride toothpastes of 1,000 ppm or above

OBJECTIVE: To determine the clinical effectiveness of low fluoride (F) toothpastes, containing 600 ppm or less, with toothpaste containing 1,000 ppm or more fluoride in preventing dental caries. DESIGN: Systematic review of randomised controlled trials comparing low fluoride toothpastes containing 600 ppm F or less with toothpastes containing 1,000 ppm or more in children or adults. RESULTS: Seven randomised controlled trials were included. These were categorised into two groups depending on the fluoride concentration in the low fluoride group (250 and 500 ppm) and analysed separately. 250 PPM: Results of the meta-analysis were statistically significant (p = 0.002 and 0.0005) and in favour of the control group (1,000 ppm). DFS increments in the 250-ppm group were 0.6-0.7 greater than the 1,000-ppm group. 500 PPM: Only two studies were in this category, and one of them failed to present the baseline caries levels, so a meta-analysis was not carried out. CONCLUSION: 250 ppm fluoride dentifrice was not as effective in caries prevention in permanent dentition as dentifrice containing 1,000 ppm F or more. More studies have to be carried out to test the anticaries efficacy of 500 against 1,000 ppm and above.     

The anti‐caries efficacy of a silica‐based fluoride toothpaste containing zinc citrate,triclosan, vitamin E and sunflower oil

Aim : To evaluate the ability of a new fluoridated toothpaste, containing 1450 ppm fluoride (as sodium fluoride), vitamin E and sunflower oil, to reduce the acid‐dissolution of sound dental enamel (demineralisation study), promote remineralisation of demineralised enamel (remineralisation study) and deliver and incorporate fluoride into demineralised enamel (fluoride uptake), when compared to a clinically‐tested fluoride toothpaste and a non‐fluoride negative control toothpaste. Methods : The de‐ and remineralisation studies both utilised pH cycling protocols. In the demineralisation study, sound enamel sections were used and efficacy was measured by calcium analysis of experimental solutions. For the remineralisation study, artificial carious lesions were microradiographed before and after pH‐cycling. For fluoride‐uptake, lesions were immersed in slurries of the toothpastes and subsequently, an acid‐etching technique was used to sample the lesions. Results : Expressed as mean values (SD), for the new fluoride toothpaste, the positive and negative controls respectively were: demin study, calcium demineralisation rate = 0.0980 (0.010), 0.110 (0.009) and 0.493 (0.043) μg Ca.mm‐2.h‐1; remin study, Δ;Z = 20.7 (16.6), 24.6 (14.9) and ?34.7 (13.1) %; F‐uptake = 27.8 (1.56), 29.6 (2.00) and 1.06 (0.430) μg F.cm‐2. Compared with the negative control, both the positive control and the test toothpaste significantly reduced enamel demineralisation and increased both remineralisation and fluoride uptake to enamel. There were no significant differences between the new fluoride toothpaste and positive control. Conclusion : Fluoride delivered from the new silica‐based toothpaste containing vitamin E and sunflower oil was as effective as that delivered from a clinically proven toothpaste.     

Timing of fluoride toothpaste use and enamel-dentin demineralization

It is well established that fluoride (F) prevents caries development by inhibiting demineralization and enhancing remineralization processes. However, it is not known which of these protective mechanisms is more important. In this double-blind, crossover in situ study conducted in three phases of 14 days each, 12 volunteers wore palatal appliances containing enamel and root dentin slabs, on which biofilm was allowed to accumulate under exposure to 20% sucrose solution 8×/day. F toothpaste was used once a day, either before the daily demineralizing episodes (in the morning) or after them (at night). Non-F placebo toothpaste was used in the control group. F toothpaste significantly reduced enamel and dentin demineralization compared with the control (p < 0.05). F toothpaste was more effective when used after the demineralization episodes than before, and this difference was statistically significant for dentin (p < 0.05). The results suggest that brushing with F dentifrice at night to remineralize daily mineral losses may be preferable to brushing in the morning to inhibit the demineralizing episodes of the day.     

In vitro efficacy of a whitening toothpastecontaining calcium carbonate and perlite

Objectives : The studies described in this paper aimed to assess the stain removal efficacy, fluoride efficacy and abrasivity to enamel and dentine of a new whitening toothpaste containing calcium carbonate and perlite, using appropriate in vitro models. Methods : Stain removal efficacy was assessed using the pellicle cleaning ratio (PCR) method. Fluoride efficacy was assessed using remineralisation, demineralisation and fluoride‐uptake methods. Abrasivity was assessed using an enamel and dentine wear method. Results : The results showed that the new whitening toothpaste was able to remove extrinsic tooth stain more effectively than three commercially available toothpaste formulations. The fluoride efficacy was superior to a non‐fluoridated control and was not significantly different to a clinically tested fluoride‐containing toothpaste. The abrasivity data showed that the calcium carbonate/perlite toothpaste is no more abrasive to enamel or dentine than two other commercially available whitening toothpastes. Conclusions : The studies show that the new whitening toothpaste is effective in extrinsic stain removal, has an efficacious fluoride source and does not have an undue degree of abrasivity to enamel or dentine compared to other relevant commercially available products.     

含氟牙膏对固定矫治中牙釉质脱矿预防效果的研究

目的：探讨含氟牙膏在正畸固定矫治中对预防牙釉质脱矿的作用。方法本实验通过常规口腔卫生宣教指导接受固定矫治器治疗的患者分别使用不同种牙膏刷牙,将患者随机分为氟化物组和对照组,氟化物组采用含氟牙膏刷牙,对照组采用不含氟牙膏刷牙,应用时间平均18个月。分别比较矫治前后两组患者及被观察牙齿牙釉质脱矿发病率和脱矿程度,判断含氟牙膏在固定矫治中对牙釉质脱矿的预防效果。结果在正畸固定矫治中,应用氟浓度为0．15%的含氟牙膏刷牙,可明显降低牙釉质脱矿的发病率,明显减少牙釉质3度脱矿的发生。结论0．15%含氟牙膏应用于固定矫治能够降低牙釉质脱矿的程度。     

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.     

Enamel demineralization in situ with various frequencies of carbohydrate consumption with and without fluoride toothpaste.

There is little information in the literature on the relationship among the frequency of carbohydrate consumption, the use of fluoride toothpaste, and enamel demineralization. The aim of this investigation was to compare the extent of demineralization of enamel slabs in situ, with a sugar-based solution, consumed in constant amounts but with various frequencies in subjects both with and without the use of fluoride (F) toothpaste. Eight subjects wore removable mandibular appliances carrying an enamel slab cut from white-spot lesions. The subjects were required to drink 500 mL of a 120-gm/L sugar solution either once, 3, 5, 7, or 10 times/day for 30 sec on each occasion, for a period of 5 days while brushing their teeth twice daily with either a F (1450 ppm NaF) or a F-free toothpaste. Mineral analysis revealed that when the subjects used a F toothpaste, net demineralization was evident only with the seven- and 10-times/day regime (ns). When F-free toothpaste was used, statistically significant demineralization was observed when the frequency exceeded 3 times/day. This study demonstrates the importance of F-containing toothpaste in enamel re-/demineralization by varying the frequency of carbohydrate challenge     

In vitro cariostatic effect of whitening toothpastes in human dental enamel-microhardness evaluation.

OBJECTIVE: The aim of this study was to evaluate, in vitro, the cariostatic effect of whitening toothpastes. METHODS AND MATERIALS: Ninety-five dental fragments were obtained from nonerupted third molars. The fragments were embedded in polystyrene resin and sequentially polished with abrasive papers (400-, 600-, and 1,000-grit) and diamond pastes of 6, 3, and 1 microm. The fragments were assigned in five groups according to toothpaste treatment: G1 = Rembrandt Plus with Peroxide; G2 = Crest Dual Action Whitening; G3 = Aquafresh Whitening Triple Protection; and the control groups: G4 = Sensodyne Original (without fluoride); G5 = Sensodyne Sodium Bicarbonated (with fluoride). The initial enamel microhardness evaluations were done. For 2 weeks the fragments were submitted daily to a de-remineralization cycle followed by a 10-minute toothpaste slurry. After that, the final microhardness tests were done. The percentage of mineral loss of enamel was determined for statistical analysis. Analysis of variance and the Tukey test were applied. RESULTS: The results did not show statistically significant differences in mineral loss among groups G1, G2, G3, and G5, which statistically differ from G4 (toothpaste without fluoride). G4 showed the highest mineral loss (P < or = .05). CONCLUSION: The whitening toothpastes evaluated showed a cariostatic effect similar to regular, nonwhitening toothpaste.     

4种防龋方法在固定矫治中预防牙釉质脱矿的研究

目的:比较4种防龋方法在正畸固定矫治中预防牙釉质脱矿的效果.方法:采用固定矫治器矫治的200名患者随机分为4组(n=50),分别用普通牙膏、含氟牙膏、氟保护漆和护牙素对牙釉质进行处理,定期随访,比较矫治完成后4组患者的牙釉质脱矿情况.结果:按牙齿数计算含氟牙膏、普通牙膏、氟保护漆和护牙素4组牙釉质的脱矿率分别为16.3％、21.9％、9.3％和8.5％ (x2=99.7,P=0.000001)氟保护漆和护牙素组脱矿率低于其他2组,该2组脱矿率之间的差异无统计学意义(x2=0.39,P=0.529851).结论:应用含氟制剂可以有效预防固定矫治中牙釉质脱矿的发生,护牙素和氟保护漆的效果更明显.     

Evaluation of the effects of a pyrophosphate-fluoride anticalculus dentifrice on remineralization and fluoride uptake in situ.

Enamel slabs and thin sections with artificially formed caries lesions were placed in the removable dentures of 15 subjects who brushed them three times daily for 2 weeks with a 1.3% pyrophosphate/1,100 ppm F/1.5% Gantrez dentifrice, a 1,100-ppm F dentifrice without pyrophosphate or Gantrez, or a placebo dentifrice in a double-blind, crossover study. Analysis of the thin sections by quantitative microradiography showed that the pyrophosphate/F dentifrice remineralized the lesions 15.9% (p less than 0.05) and the fluoride dentifrice 11.2%, whereas the placebo produced 4.4% demineralization. Fluoride uptake by the enamel slabs was similar for both fluoride dentifrices and significantly greater from the placebo dentifrice (p less than 0.05). The findings suggest that the anticaries mechanisms of fluoride include not only the prevention of demineralization, but also the promotion of remineralization.