Monofluorophosphate Research Articles

Evaluation of total, soluble and ionic fluoride concentration in whitening and desensitizing toothpastes.

Due to the popularity and increasing launch of toothpastes with whitening and sensitivity properties on the market, this study aimed to evaluate the fluoride concentrations in these products, since the concentrations of fluoride directly interfere with the anti-caries potential. This is an experimental, invitro study, where 37 samples from different batches (n = 3) purchased in different countries, were analysed in duplicate, via the ion-selective electrode technique to verify the concentration (μg/g or ppm F-) of total fluoride (TF), total soluble fluoride (TSF) and ionic fluoride (IF). For a comparative data analysis, ANOVA was applied followed by a Tukey's test for multiple comparisons. The level of confidence adopted was 95%. In the 37 assessed toothpastes, 45.9% contained NaF and 54.1% sodium monofluorophosphate (MFP). The TF found in the formulations ranged from 902.8 to 1539.4 ppm of F (mean: 1165.2 ± 179.3); fluoride concentration in the TSF fraction ranged from 708.8 to 1306.7 ppm of F (mean: 959.5 ± 162.4); IF results ranged from 101.9 to 1162.3 ppm of F (642.2 ± 294.1). Significant differences (p < 0.05) were found in the concentrations of the 59.5% assessed toothpastes in comparisons between declared and measured total fluoride (TF) concentrations, as well as in 62.2% when total fluoride (TF) and total soluble fluoride (TSF) were compared. In this study, most of the samples evaluated showed discrepancies when compared to the information declared by the manufacturers. In addition, the soluble concentrations found in half of the samples were lower than total concentrations and this may affect anti-caries effectiveness.

Corrosion protection of steel bar enabled by monofluorophosphate-bearing composites with sustained-release capability

This paper selected the polyethylene (PE) and polystyrene (PS) as polymer carriers of the sodium monofluorophosphate (MFP) to prepare PE/MFP and PS/MFP composites using melt-extrusion technique with a sustained-release capacity for smart corrosion protection. The releasing behavior of two MFP-containing composites in the simulated concrete pore solution was evaluated in terms of residual content, releasing rate and the side/fractured surface micro-morphologies. Besides, related releasing mechanisms of MFP-bearing polymer composites are explained, which are different from the mechanisms of most microcapsules and tablets. The experimental analyses showed that two composites all displayed a uniform elemental distribution on their side surface and intrinsic hydrophobicity. The PE/MFP composites obtained higher initial encapsulation efficiency and a lower but relatively controllable releasing rate compared to the PS/MFP composites due probably to the higher hydrophobicity and crystallinity of the PE carrier. In addition, the physical appearance of the corroded carbon steel bar after immersion in sodium chloride-contaminated simulated concrete pore solutions and corresponding electrochemical outcomes revealed that PE/MFP composites generally led to better corrosion protection performance than the PS/MFP counterpart, which could be due to their better sustained-release capacity. The obtained composites provide another promising option as concrete inhibitors, making inroads into improving the long-term durability of concrete structures.

Determination of bioavailable fluoride in toothpastes marketed in Medellín, Colombia, through capillary electrophoresis

Currently, the FDI recommendation (World Dental Federation) for fluoride concentration in toothpastes is that the total fluoride content declared by manufacturers be between 1,000 and 1,500 ppm, and of this amount, at least 800 ppm should be bioavai­lable fluoride. The aim of this study was to describe the market of toothpastes marketed in Medellín and to measure the concentration of bioavailable fluoride by capillary electrophoresis to verify their compliance with the FDI recommendation for the prevention of dental caries. After sampling the toothpastes available for sale in the 16 communes of the city of Medellin, a single operator measured in triplicate the concentration of bioavailable fluoride in 36 samples of previously blinded toothpastes using the capi­llary electrophoresis (EC) technique. Most of the evaluated toothpastes that declared a content of 1,000–1,500 ppm fluoride met the recommendation of presenting at least 800 ppm bioavailable fluoride. Measurement of bioavailable fluoride in toothpastes with MFP (sodium monofluorophosphate) is recommended, as it is known that binding to the abrasive can decrease its concentration over time.

Salivary fluoride concentrations following toothbrushing with experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler.

Single-blind 9 case comparative studies were conducted to evaluate salivary fluoride concentrations following toothbrushing using experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) fillers. Preliminary tests were conducted in order to determine the volume of usage as well as the concentrations (wt %) of S-PRG filler. Based on the results given these experiments, we compared the salivary fluoride concentrations following toothbrushing with 0.5g of 4 different types of toothpastes: 5 wt % S-PRG filler, 1400ppm F AmF (amine fluoride), 1500ppm F NaF (sodium fluoride), and MFP (monofluorophosphate) containing toothpaste. Of the 12 participants, 7 participated in the preliminary study and 8 in the main study. All participants brushed their teeth using the scrubbing method for 2min. At first, 1.0 and 0.5g of 20 wt % S-PRG filler toothpastes were used to compare, then followed by 0.5g of 0 (control), 1, and 5 wt % S-PRG toothpastes, respectively. The participants spat out once and rinsed with 15mL of distilled water for 5s. Saliva was collected for 3min each at different time intervals of 0 (baseline), 5, 10, 15, 30, 60, 120, and 180min after the rinsing. Fluoride concentrations were determined using a fluoride electrode, and the area under the salivary clearance - time curve (AUC: ppm‧min) of each toothpaste was calculated as the salivary fluoride retention. The main study was then conducted to evaluate the salivary fluoride concentrations as well as the AUC value using 0.5g of 5 wt % S-PRG filler toothpaste, followed by NaF, MFP, and AmF toothpastes. Since there were no statistical differences between using 1.0 and 0.5g of 20 wt % S-PRG toothpastes in salivary fluoride concentrations as well as the AUC value throughout the 180min measurement, the volume was set as 0.5g for the following studies. Concentrations of 5 and 20 wt % S-PRG toothpastes retained 0.09ppm F or more in saliva even after 180min. No statistical differences were seen in the salivary fluoride concentrations at any time intervals as well as the AUC value between 5 and 20 wt % S-PRG toothpastes. Based on these results, the concentration of 5 wt % S-PRG toothpaste was used for the main comparative study. MFP toothpaste resulted in by far the lowest salivary fluoride concentrations (0.06ppm F at 180min) and the AUC value (24.6ppm‧min), whereas 5 wt % S-PRG toothpaste (0.15ppm F at 180min, 92.3ppm‧min) displayed retention on par with AmF toothpaste which appeared to result in higher values (0.17ppm F at 180min, 103ppm‧min), compared to NaF toothpaste (0.12ppm F at 180min, 49.3ppm‧min). The salivary fluoride concentrations following toothbrushing with 0.5g of 5 wt % S-PRG filler containing toothpaste showed retention similar to the best performing 1400ppm F AmF toothpaste even 180min after toothbrushing.

Fluoride concentration in dentifrices marketed In Argentina.

The objective of this study was to determine the different forms of fluoride available in dentifrices commercialized in Argentina. Thirty three different brands of fluoridated dentifrices were purchased in different cities of Argentina. The total fluoride (TF), total soluble fluoride (TSF) and ionic fluoride (IF) of two samples of each brand were analysed (μg F/ml) by ion-specific fluorine electrodes. A total of 67% of dentifrices showed fluoride content that compromises anti-caries activity. A total of 54.5% was formulated with sodium fluoride (NaF), 36.3% formulated with sodium monofluorophosphate (MFP), 3% NaF associated with MFP and 9% formulated with stannous fluoride (SnF2). The TF found was less than the amount declared by the manufacturer in all the brands analysed. The concentration of TF found in the fluoride dentifrices ranged from 590.3 to 1381.4μg/ml F, TSF ranged from 343.1 to 1258.3μg/ml F, and IF ranged from 13.1 to 913μg/ml F. The concentrations of TF were below the reported values. TSF and IF were lower than the total fluoride concentration. Most of the samples studied have TSF concentration that compromises anti-caries effect. Additional studies with a larger number of samples are suggested to obtain more data.

Fluoride content in paediatric dentifrices commercialized in Brazil.

The aim of this study is to determine the total, soluble and ionic fluoride (IF) concentration in toothpastes for children since there is a lack of information about this data. Fifteen different brands of toothpastes were purchased in different cities in Brazil. The total fluoride (TF), total soluble fluoride (TSF) and IF of two samples of each brand were determined (μg/g F). The concentration of TF found in the fluoride toothpastes ranged from 324.4 to 1466.2μg/g F, TSF ranged from 214.6 to 1424.1μg/g F and IF ranged from 108.3 to 1320.1μg/g F. TSF ranged between TF and IF. Most toothpastes were formulated with sodium fluoride (NaF), and only one with monofluorophosphate (MFP). The concentrations of TF were below the reported values. TSF and IF were below the TF concentration. The measured TF was less than that declared by the manufacturer in all the products. Most of the evaluated fluoride toothpastes commercialized in Brazil showed concentrations of TF below what was stated on the packaging, but with enough TSF to provide an anti-caries effect.

Improved Enamel Acid Resistance by Highly Concentrated Acidulated Phosphate Sodium Monofluorophosphate Solution.

Sodium monofluorophosphate (MFP) is a component of fluoride-containing dentifrices and is more biosafe than the conventional sodium fluoride (NaF). MFP can respond not only on the tooth surface layer but also deep into the enamel. We aim to confirm that high concentrations of acid phosphate MFP (AP-MFP, 9000 ppmF), used in professional care, could lead to a highly biosafe fluoride application method that acts through the deep enamel layers. Sample groups were respectively treated in vitro with NaF, acidulated phosphate fluoride (APF), MFP, and AP-MFP, and the samples were compared against an untreated group. Characterizations after fluoride application confirmed that MFP and AP-MFP treatments improved the acid resistance of enamel compared to that of conventional methods. Furthermore, the acid resistance of highly concentrated MFPs improved by using phosphoric acid. Although the acid resistance from the AP-MFP method is not as good as that using APF, AP-MFP can act both on the surface layer and deep into the enamel. Moreover, AP-MFP retains fluoride ions as much as APF does on the tooth surface. The proposed fluoride application method using AP-MFP introduces a dental treatment for acid resistance that is highly biosafe and penetrates deep layers of the enamel.

Effect of a Stannous Fluoride Dentifrice on Biofilm Composition, Gene Expression and Biomechanical Properties.

An in situ study was conducted to examine the mode of action of a 0.454% stannous fluoride (SnF2)-containing dentifrice in controlling the composition and properties of oral biofilm. Thirteen generally healthy individuals participated in the study. Each participant wore an intra-oral appliance over a 48-h period to measure differences in the resulting biofilm’s architecture, mechanical properties, and bacterial composition after using two different toothpaste products. In addition, metatranscriptomics analysis of supragingival plaque was conducted to identify the gene pathways influenced. The thickness and volume of the microcolonies formed when brushing with the SnF2 dentifrice were dramatically reduced compared to the control 0.76% sodium monofluorophosphate (MFP)-containing toothpaste. Similarly, the biophysical and nanomechanical properties measured by atomic force microscopy (AFM) demonstrated a significant reduction in biofilm adhesive properties. Metatranscriptomic analysis identified pathways associated with biofilm formation, cell adhesion, quorum sensing, and N-glycosylation that are significantly downregulated with SnF2. This study provides a clinically relevant snapshot of how the use of a stabilized, SnF2 toothpaste formulation can change the spatial organization, nanomechanical, and gene expression properties of bacterial communities.

Effect of sodium monofluorophosphate and phosphates on mechanical properties and water resistance of magnesium oxychloride cement

Weak water resistance of magnesium oxychloride cement (MOC), an eco-friendly construction material, has been a notorious and critical issue of MOC, restricting its application to mostly indoor with dry service environment. In this paper, sodium monofluorophosphate (MFP) is innovatively used, the first time, as a modifier to enhance the water resistance of MOC, as the PO3F2− ions in MFP solution form amorphous phase in MOC, which helps to improve the water repellence of MOC. The effect of MFP with different content, different mixing and curing methods on water resistance of MOC is studied. The effect of phosphates, including phosphoric acid (H3PO4) and soluble phosphates (KH2PO4) with various content on water resistance of MOC is also investigated and compared with the effect of MFP on the water resistance of MOC. The effects of these additives on the physical and mechanical properties of MOC, such as setting time, fluidity, compressive strength, flexural strength, are studied. To reveal the water resistance mechanism, XRD, FTIR, TG/DSC, MIP and SEM-EDS are conducted on the modified MOC. It is found that MFP has similar effect on the mechanical properties of MOC as H3PO4 and KH2PO4, and they all significantly increase the flexural strength, slightly decrease the compressive strength, and remarkably increase the water resistance of MOC. The highest compressive strength retention coefficient of 0.84, 0.98, and 0.95 was achieved for 1% KH2PO4-MOC, 1% H3PO4-MOC, and 1% MFP-MOC respectively. From the microscale study, it is found that the addition of H3PO4, KH2PO4, and MFP changes the growth direction and morphology of the phase 5 crystals, which contributes to the increase of the water resistance of MOC.

An Aptasensing Strategy Using the Phosphatase‐mimic Nanozyme and pH Meter as Signal Readout

AbstractThe demand for point‐of‐care testing (POCT) is growing dramatically, especially for district where health facilities are poorly staffed, poorly skilled and ill‐equipped. As a commercialized portable device, pH meters can be used for detection of various targets, relying on bioactive enzymes. The nanozymes, as the alternative of the natural enzymes, have rarely been used for pH‐metric POCT strategies. Herein, we developed an ultrasensitive pH‐metric sandwich‐type aptasensor based on the CeO2 nanorods (CeO2 NRs) as phosphatase‐mimic and sodium monofluorophosphate (MFP) as catalytic substrate. Under optimal conditions, such strategy yields a detection limit of 1.17 nM with eligible selectivity for detecting thrombin.

Experimental study on multi-component corrosion inhibitor for steel bar in chloride environment

This paper investigates one type of multi-component corrosion inhibitor for steel bars in chloride environment. Triethanolamine (TEA), tri-isopropanolamine (TIPA), sodium monofluorophos-phate (MFP) and sodium molybdate (T-4) were proportioned to prepare this multi-component corrosion inhibitor. Corrosion behavior of steel bar was evaluated using the polarization curve, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The polarization curves were fitted using the adsorption isotherm models. Experimental results indicated that the steel bar corrosion in chloride solution can be reduced by the addition of either organic or inorganic corrosion inhibitors. This is attributed to the fact that organic corrosion inhibitor can form an adsorption film on the steel bar surface and inorganic corrosion inhibitor abates electrochemical reaction of steel bars. Compared to single component corrosion inhibitors, the corrosion rate of steel bars in simulated pore solution was significantly restrained by the multi-component corrosion inhibitor. The adsorption of multi-component corrosion inhibitor on the surface of steel bar can significantly reinforce the passive film by means of physical (organic) or chemical (inorganic) process. For all the investigated corrosion inhibitors, the adsorption isotherms were in good agreement with experimental results. The EIS result and equivalent electrochemical circuit confirmed the chemical reaction and physical adsorption process of the multi-component corrosion inhibitor. Therefore, the chloride induced corrosion of steel bars can be effectively controlled by the multi-component corrosion inhibitor.

In situ evaluation of desensitizing toothpastes for protecting against erosive tooth wear and its characterization

This five-phase, single-blind, crossover in situ trial evaluated the effects of desensitizing or anti-erosive toothpastes on dentin erosive wear and tubule occlusion. Some characteristics such as relative dentin abrasivity (RDA), viscosity (V), cytotoxicity, and fluoride and calcium (Ca) availability of the toothpastes were also tested. Samples were positioned on removable intraoral appliances from 15 volunteers (n=4), according to the groups, C-control (0 ppm fluoride), F-sodium monofluorophosphate (MFP), A-MFP and arginine+calcium carbonate, CSP-calcium sodium phosphosilicate, and CS-MFP and calcium silicate+sodium phosphate. Erosion-abrasion cycling was performed (1% citric acid, 2min, 6×/day; toothbrushing, 5s, 2×/day). Surface loss (SL) was evaluated by optical profilometry. Environmental scanning electron microscopy images (ESEM) counted the number of open dentin tubules (ODTs). Data were statistically analyzed (α=0.05). There were no significant differences in SL among groups (p=0.468). The ODT for CSP, CS, and A groups were significantly lower than the control. CSP and CS presented significantly less ODT than F, but they did not significantly differ from A. F and CS were more abrasive than all the other toothpastes; CSP was more abrasive than A, and C was the least abrasive. CSP presented higher V (p<0.05). All toothpastes presented lower cell viability than the control without toothpaste exposure. F and A presented significantly higher values of F- (p<0.05). All fluoride toothpastes had similar amount of Ca, differing from the control (p<0.05). Although the toothpastes caused similar degree of erosive wear, CSP and CS were able to occlude the dentin tubules. Desensitizing toothpastes containing calcium, sodium, phosphate, and silicate could be a suitable option for treating dentin hypersensitivity.

Comparative evaluation of the efficacy of three commercially available toothpastes on dentin hypersensitivity reduction: an 8-week clinical study

Objective: The objective of this 8-week, single-center, double-blind, three-cell, randomized, clinical study was to compare the efficacy in reducing the dentin hypersensitivity of three commercially available toothpaste: Group A toothpaste containing 8.0% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate; Group B toothpaste containing 8% strontium acetate and 1040 ppm fluoride as sodium fluoride; and Group C toothpaste containing 5% potassium nitrate and 917 ppm fluoride as sodium monofluorophosphate. Materials and Methods: One hundred and fifty subjects, who reported to the department having teeth sensitive to tactile and air blast hypersensitivity, were assigned to one of the three study groups (50/group). Subjects were then asked to brush their teeth for 1 min, twice daily, with the given toothpaste. The dentin hypersensitivity of the two selected teeth was evaluated at baseline, 2 weeks, 4 weeks, and 8 weeks. Comparison of the treatment groups was conducted using the VAS analysis. Results: All 150 subjects complied with the protocol and completed the 8-week clinical study; there were no adverse events on the soft or hard tissues of the oral cavity. Group A resulted in more improvement in the reduction of sensitivity at 2, 4, and 8 weeks compared to the other groups. Conclusions: Group A toothpaste containing 8.0% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate significantly reduces dentin hypersensitivity and more effective than Group B and Group C toothpaste. Group A toothpaste is the latest new tool in the armament of the modern dentist.

The influence of brushing with theobromine and sodium monofluorophosphate toothpaste on enamel surface resistance to roughness after demineralization

Herein, the influence of brushing with theobromine and sodium monofluorophosphate toothpaste on enamel surface roughness resistance after demineralization was determined. Overall, 21 human premolar enamel specimens were ground, polished, divided into three groups, and brushed for 5 minutes each with theobromine toothpaste, with sodium monofluorophosphate (MFP) toothpaste, or without toothpaste (control group). Next, specimens from the three groups were immersed in 20 ml of Coca-Cola® for 75 minutes. Surface roughness was measured before brushing, after brushing, and after immersion. Repeated ANOVA tests in the control group showed a non-significant (p > 0.05) increase in roughness after brushing and a significant increase (p < 0.05) in roughness after immersion. The theobromine group showed a significant (p < 0.05) increase in roughness after brushing and non-significant (p > 0.05) increase after immersion, and the MFP group showed a significant (p < 0.05) increase in roughness after brushing and after immersion. One-way ANOVA test showed that the theobromine group had the lowest increase in roughness (p > 0.05) after immersion, but it was not statistically significant compared to brushing using MFP. Therefore, brushing with theobromine toothpaste maintains enamel surface roughness after demineralization in Coca-Cola® and is slightly better than brushing with MFP toothpaste.

In situ anticaries efficacy of dentifrices with different formulations – A pooled analysis of results from three randomized clinical trials

ObjectivesData generated from three similar in situ caries crossover studies presented the opportunity to conduct a pooled analysis to investigate how dentifrice formulations with different fluoride salts and combinations at concentrations of 1400–1450 ppm F, different abrasive systems and in some cases, carbomer (Carb), affect enamel caries lesion remineralization and fluoridation. MethodsSubjects continuously wore modified partial dentures holding two gauze-covered partially-demineralized human enamel specimens for 14 days and brushed 2×/day with their assigned dentifrice: Study 1: sodium fluoride (NaF)/Carb/silica, NaF/silica, NaF + monofluorophosphate (MFP)/chalk; Study 2: NaF/Carb/silica, NaF + MFP/dical, amine fluoride (AmF)/silica; Study 3: NaF/Carb/silica, NaF + stannous fluoride (SnF2)/silica/hexametaphosphate (HMP). All studies included Placebo (0 ppm F) and/or dose-response controls (675 ppm F as NaF [675F-NaF]) ±Carb. Specimens were evaluated for percentage surface microhardness recovery (SMHR) and enamel fluoride uptake (EFU). ResultsAll 1400–1450 ppm F dentifrices except NaF + SnF2/silica/HMP provided significantly greater lesion remineralization than Placebo (p < 0.0001): differences in SMHR ranged from 17.46% (NaF + MFP/dical) to 26.66% (AmF/silica). For EFU (back-transformed log EFU), all 1400–1450 ppm F dentifrices gave significant fluoride uptake compared to Placebo (p < 0.0001): increases in EFU ranged from 4.95 μg F/cm2 (NaF + SnF2/silica/HMP) to 16.32 μg F/cm2 (NaF/carb/silica). Dentifrices containing NaF or AmF as sole fluoride source provided the greatest remineralization and fluoridation; Carb addition did not alter fluoride efficacy; some excipients appeared to interfere with the cariostatic action of fluoride. Treatments were generally well-tolerated with ≤4 treatment-related adverse events per study. ConclusionCommercially available fluoride dentifrices varied greatly in their ability to remineralize and fluoridate early caries lesions. Clinical significanceFluoride dentifrices are the most impactful anticaries modality worldwide. While clinical caries trials have not consistently shown the superiority of one formulation over another, these findings using a sensitive in situ caries model indicated that dentifrices containing NaF or AmF as the sole fluoride source provided the greatest remineralization and fluoridation benefits.

Photometric and fluorometric alkaline phosphatase assays using the simplest enzyme substrates

In this contribution a highly cost-effective flow analysis system for determination of alkaline phosphatase (ALP) activity is presented. This fully-mechanized bioanalytical system is based on economic solenoid micropumps and microvalves (powered and actuated by Arduino microcontroller) and extremely cheap dedicated optoelectronic flow-through detectors allowing absorbance and fluorescence measurements. The detection schemes for ALP assaying realized in this system are based on orthophosphate determination. For the detection of these ions formed in the course of enzymatic conversion a molybdate method requiring only common and inexpensive chemicals is utilized. Thus, for the enzymatic assays the simplest not-chromogenic/not-fluorogenic ALP substrates can be applied. Such approach results in the use of low-cost reagents for ALP assays, whereas the mechanization of assay causes low consumption of reagents as well as samples. In the course of reported investigations six ALP substrates were examined and the most promising results have been obtained for the inorganic compound – monofluorophosphate (MFP). The obtained linear ranges of absorbance and fluorescence measurements are 100–600 U L−1 and 30-30/30-100 U L−1, with sensitivities of 0.7 mV L−1 U−1 and 2.3/1.0 mV L−1 U−1, respectively. The calculated limits of detection are 5.1 U L−1 (photometry) and 0.9 U L−1 (fluorometry). The throughputs of the developed system are 13 and 12 samples/h for photometric and fluorometric detections, respectively. To demonstrate the practical utility of the developed bioanalytical system the ALP assays in complex matrix samples have been carried out. The results of ALP activity determination in serum samples are well-correlated with those obtained using reference method recommended for routine clinical analysis.

In-vitro apatite formation capacity of a bioactive glass - containing toothpaste

ObjectivesThe in-vitro dissolution of bioactive glass-based toothpastes and their capacity to form apatite-like phases in buffer solutions have been investigated. Materials and methodsThe commercial toothpaste samples were tested on immersion in artificial saliva, Earle’s salt solution and Tris buffer for duration from 10min to four days. The powder samples collected at the end of the immersion were studied using solid-state 31P and 19F nuclear magnetic resonance spectroscopy (NMR), X-ray powder diffraction and Fourier transform infrared (FTIR) spectroscopy. The fluoride concentration in the solution remained after the immersion was measured. ResultsIn artificial saliva and in presence of sodium monofluorophosphate (MFP), the bioactive glass and bioactive glass-based toothpastes formed fluoridated apatite-like phases in under 10min. A small amount of apatite-like phase was detected by 31P NMR in the toothpaste with MFP but no bioactive glass. The toothpaste with bioactive glass but no fluoride formed an apatite-like phase as rapidly as the paste containing bioactive glass and fluoride. By contrast, apatite-like phase formation was much slower in Earle’s salt solution than artificial saliva and slower than Tris buffer. ConclusionsThe results of this lab-based study showed that the toothpaste with MFP and bioactive glass formed a fluoridated apatite in artificial saliva and in Tris buffer, as did the mixture of bioactive glass and MFP. Clinical significanceThe presence of fluoride in bioactive glass-containing toothpastes can potentially lead to the formation of a fluoridated apatite, which may result in improved clinical effectiveness and durability. However, this should be further tested intra-orally.

Characteristics and release property of polylactic acid/sodium monofluorophosphate microcapsules prepared by spray drying

Microcapsules composed of polylactic acid (PLA)/corrosion inhibitor sodium monofluorophosphate (MFP) were prepared by spray drying, and the effects of processing parameters on the morphology and encapsulation efficiency of the microcapsules were investigated. The results showed that low viscous PLA solution only resulted in porous microcapsules with low encapsulation efficiency, whereas filamentous substances were produced instead of microcapsules once PLA solution content exceeded 5%. When spray pressure exceeded 0.4MPa, the microcapsule surface was wrinkled due to high evaporation rate of the atomized droplets. The spray pressure less than 0.3MPa created larger atomized droplets and yielded the adhesive microcapsules with lower encapsulation efficiency. The optimal emulsion parameters were as follows: PLA concentration, 5%; water-oil ratio, 1:9; inlet air temperature, 50°C; and spray pressure, 0.4MPa. The resulting microcapsules exhibited a good sustained-release behavior in a simulated concrete pore solution.

The use of a Phosphate-Based Migrating Corrosion Inhibitor to Repair Reinforced Concrete Elements Contaminated by Chlorides

The use of sodium monofluorophosphate (MFP) was experimented as migrator inhibiting treatment against corrosion of reinforced concrete elements induced by chlorides. The results show that sodium monofluorophosphate, applied by surface impregnation, is able to slow down reinforcement corrosion only for reinforcing steel bars with concrete cover not thicker than 1 cm. This limitation is most probably due to the difficulty, with the type of application adopted, in making MFP to reach concentrations high enough to inhibit the corrosive process at greater depths from the impregnation surface.

Monofluorophosphate Blocks Internal Polysaccharide Synthesis in Streptococcus mutans.

Streptococcus mutans is the leading cause of dental caries worldwide by accumulating a glycogen-like internal polysaccharide (IPS) that contributes to cariogenicity when sugars are in excess. Sodium monofluorophosphate (MFP) is an active anticariogenic compound in toothpastes. Herein, we show that MFP inhibits (with an I0.5 of 1.5 mM) the S. mutans ADP-glucose pyrophosphorylase (EC 2.7.7.27), which catalyzes the key step in IPS biosynthesis. Enzyme inhibition by MFP is similar to orthophosphate (Pi), except that the effect caused by MFP is not reverted by fructose-1,6-bisP, as occurs with Pi. Inhibition was correlated with a decrease in acidogenesis and IPS accumulation in S. mutans cells cultured with 2 mM sodium MFP. These effects were not mimicked by sodium fluoride. Considering that glycogen synthesis occurs by different pathways in mammals and bacteria, ADP-glucose pyrophosphorylase could be visualized as a molecular target for controlling S. mutans virulence. Our results strongly suggest that MFP is a suitable compound to affect such a target, inducing an anticariogenic effect primarily by inhibiting a key step in IPS synthesis.