In situ evaluation of a low fluoride concentration gel with sodium trimetaphosphate in enamel remineralization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In vitro enamel remineralization by low-fluoride toothpaste with calcium citrate and sodium trimetaphosphate

The objective of this study was to evaluate in vitro the effect of a low fluoride toothpaste (450 μgF/g, NaF) combined with calcium citrate (Cacit) and sodium trimetaphosphate (TMP) on enamel remineralization. Bovine enamel blocks had the enamel surface polished sequentially to determine the surface hardness. After production of artificial carious lesions, the blocks selected by their surface hardness were submitted to remineralization pH cycling and daily treatment with dentifrice suspensions (diluted in deionized water or artificial saliva): placebo, 275, 450, 550 and 1,100 μgF/g and commercial dentifrice (positive control, 1,100 μgF/g). Finally, the surface and cross-section hardness was determined for calculating the change of surface hardness (%SH) and mineral content (%ΔZ). Fluoride in enamel was also determined. The data from %SH, %ΔZ and fluoride were subjected to two-way analysis of variance followed by Student-Newman-Keuls's test (p<0.05). The mineral gain (%SH and %ΔZ) was higher for toothpastes diluted in saliva (p<0.05), except for the 450 mgF/g dentifrice with Cacit/TMP (p>0.05). The 450 Cacit/ TMP toothpaste and the positive control showed similar results (p>0.05) when diluted in water. A dose-response was observed between fluoride concentration in toothpastes and fluoride present in enamel, regardless of dilution. It was concluded that it is possible to enhance the remineralization capacity of low F concentration toothpaste by of organic (Cacit) and inorganic (TMP) compounds with affinity to hydroxyapatite.

Effect of fluoride gels supplemented with sodium trimetaphosphate on enamel erosion and abrasion: In vitro study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of fluoride varnish supplemented with sodium trimetaphosphate on enamel erosion and abrasion: An in situ/ex vivo study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

In vitro Remineralizing Effect of Fluoride Varnishes Containing Sodium Trimetaphosphate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of fluoride gels supplemented with sodium trimetaphosphate in reducing demineralization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of fluoride varnish supplemented with sodium trimetaphosphate on enamel erosion and abrasion

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In situ remineralizing effect of fluoride varnishes containing sodium trimetaphosphate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synergistic effect of fluoride and sodium hexametaphosphate in toothpaste on enamel demineralization in situ

To evaluate the effect of a fluoride dentifrice containing sodium hexametaphosphate (HMP) on enamel demineralization in situ. This double-blind and cross-over study consisted of 3 phases (7 days each) in which 12 volunteers wore intraoral appliances containing four enamel bovine blocks. Specimens were treated (3×/day) with placebo (no F or HMP), 1100ppm F (1100F) and 1100F plus HMP1% (1100F-HMP1%) toothpastes, and the cariogenic challenge was performed using a 30% sucrose solution (6×/day). Final surface hardness, the percentage of surface hardness loss (%SH), the integrated loss of subsurface hardness (ΔKHN), as well as enamel calcium (Ca), phosphorus (P) and firmly-bound fluoride (F) were determined. Also, biofilm formed on the blocks were analyzed for F, Ca, P and insoluble extracellular polysaccharide (EPS) concentrations. Data were submitted 1-way ANOVA, followed by Student-Newman-Keuls' test (p<0.05). 1100F-HMP1% promoted the lowest %SH and ΔKHN among all groups (p<0.001). The addition of HMP1% to 1100F did not enhance enamel F uptake, but significantly increased enamel Ca concentrations (p<0.001). Similar EPS concentrations were seen for 1100F-HMP1% and 1100F groups (p>0.05). All the groups were supersaturated with respect to HA. However, only 1100F-HMP1% group was supersaturated with respect to CaF2 (p<0.05). The ionic activities of F(-), CaF(+) and HF(0) for the 1100F-HMP1% group were the highest among all groups (p<0.001). The addition of HMP1% to a conventional toothpaste significantly reduces enamel demineralization in situ when compared to 1100F. This dentifrice could be a viable alternative to patients at high risk of caries.

Fluoride gel supplemented with sodium hexametaphosphate reduces enamel erosive wear in situ

This study evaluated the effect of fluoride gels, supplemented or not with sodium hexametaphosphate (HMP), on enamel erosive wear in situ. Twelve healthy volunteers wore palatal appliances containing four bovine enamel discs. Subjects were randomly allocated into four experimental phases (double-blind, crossover protocol) according to the gels: Placebo (no fluoride or HMP), 1% NaF, 2% NaF, and 1% NaF+9% HMP. Enamel discs were selected after polishing and surface hardness analysis, and treated only once with the respective gels prior to each experimental phase. Erosion (ERO) was performed by extra-oral immersion of the appliance in 0.05M citric acid, pH 3.2 (four times/day, five minutes each, 5 days). Additional abrasion (ERO+ABR) was produced on only two discs by toothbrushing with fluoridated dentifrice after ERO (four times/day, 30s, 5 days). The specimens were submitted to profilometry and hardness analysis. The results were analyzed by two-way ANOVA and the Student-Newman-Keuls test (p<0.05). The 1% NaF+9% HMP gel promoted significantly lower enamel wear for ERO compared to the other groups, being statistically lower than 1% NaF and Placebo for ERO+ABR. Similarly, the lowest values of integrated lesion area were found for 1% NaF+9% HMP and 2% NaF, respectively, for ERO and ERO+ABR. The addition of HMP to the 1% NaF gel promoted greater protective effect against ERO and ERO+ABR compared to the 1% NaF gel, achieving similar protective levels to those seen for the 2% NaF gel. Gel containing 1% NaF+9% HMP showed a high anti-erosive potential, being a safer alternative when compared to a conventional 2% NaF gel.

In vitro effect of low-fluoride toothpastes containing sodium trimetaphosphate on enamel erosion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of strong acids on red mud structural and fluoride adsorption properties

The removal of fluoride using red mud has been improved by acidifying red mud with hydrochloric, nitric and sulphuric acid. This investigation shows that the removal of fluoride using red mud is significantly improved if red mud is initially acidified. The acidification of red mud causes sodalite and cancrinite phases to dissociate, confirmed by the release of sodium and aluminium into solution as well as the disappearance of sodalite bands and peaks in infrared and X-ray diffraction data. The dissolution of these mineral phases increases the amount of available iron and aluminium oxide/hydroxide sites that are accessible for the adsorption of fluoride. The removal of fluoride is dependent on the charge of iron and aluminium oxide/hydroxides on the surface of red mud. Acidifying red mud with hydrochloric, nitric and sulphuric acid resulted in surface sites of the form ≡ SOH2+ and ≡ SOH. Optimum removal is obtained when the majority of surface sites are in the form ≡ SOH2+ as the substitution of a fluoride ion doesn’t cause a significant increase in pH. This investigation shows the importance of having a low and consistent pH for the removal of fluoride from aqueous solutions using red mud.

Studies on the reactions of thionyl fluoride

Thionyl fluoride undergoes quantitative oxidation with chloramine-T and reduction with lithium aluminium hydride and sodium borohydride. At elevated temperatures, (>150°C) it reacts with metals such as copper, silver, zinc and lead forming the corresponding metal sulphides, fluorides and sulphur dioxide. With the respective metal oxides, the metal fluorides and sulphur dioxide are formed.

Pyridinium poly(hydrogen fluoride)- a reagent for the preparation of hexafluorophosphates

Pyridinium poly(hydrogen fluoride) has been found to be an efficient and versatile reagent for the preparation of hexafluorophosphates. Pyridinium hexafluorophosphate has been prepared by the reaction between phosphorus (V) halides (POCl3, POBr3, PSCl3, PCl5, PBr5) and pyridinium poly(hydrogen fluoride). This in turn is used to prepare the hexafluorophosphates of ammonium, sodium, potassium, rubidium and cesium in good yield and high purity.