Addition Of Fluoride Research Articles

A cost-effectiveness analysis of community water fluoridation for schoolchildren

BackgroundCommunity water fluoridation (CWF), the controlled addition of fluoride to the water supply for the prevention of dental caries (tooth decay), is considered a safe and effective public health intervention. The Republic of Ireland (Ireland) is the only country in Europe with a legislative mandate for the fluoridation of the public water supply, a key component of its oral health policy. However, more recently, there has been an increase in public concern around the relevance of the intervention given the current environment of multiple fluoride sources and a reported increase in the prevalence of enamel fluorosis. The aim of this economic analysis is to provide evidence to inform policy decisions on whether the continued public investment in community water fluoridation remains justified under these altered circumstances.MethodsFollowing traditional methods of economic evaluation and using epidemiological data from a representative sample of 5-, 8-, and 12-year-old schoolchildren, this cost-effectiveness analysis, conducted from the health-payer perspective, compared the incremental costs and consequences associated with the CWF intervention to no intervention for schoolchildren living in Ireland in 2017. A probabilistic model was developed to simulate the potential lifetime treatment savings associated with the schoolchildren’s exposure to the intervention for one year.ResultsIn 2017, approximately 71% of people living in Ireland had access to a publicly provided fluoridated water supply at an average per capita cost to the state of €2.15. The total cost of CWF provision to 5-, 8-, and 12-year-old schoolchildren (n = 148,910) was estimated at €320,664, and the incremental cost per decayed, missing, or filled tooth (d3vcmft/D3vcMFT) prevented was calculated at €14.09. The potential annual lifetime treatment savings associated with caries prevented for this cohort was estimated at €2.95 million. When the potential treatment savings were included in the analysis, the incremental cost per d3vcmft/D3vcMFT prevented was -€115.67, representing a cost-saving to the health-payer and a positive return on investment. The results of the analysis were robust to both deterministic and probability sensitivity analyses.ConclusionDespite current access to numerous fluoride sources and a reported increase in the prevalence of enamel fluorosis, CWF remains a cost-effective public health intervention for Irish schoolchildren.

Innovative directions of development of ceramic materials for dentistry

The need to improve the level of dental health of the population of Ukraine was identified. The prospects for the use of ceramic prostheses to provide quality medical care in dentistry have been established. An analytical review of various types of ceramic and glass-ceramic materials used as dental prostheses for tooth replacement: porcelain, alumina, zirconium oxide, glass-ceramics based on leucite and lithium disilicate and mica with the addition of fluorides. Peculiarities of the structure and operational properties of ceramic and glass-ceramic materials for dentistry have been identified, their advantages and disadvantages have been established. The effectiveness of the use of glass-ceramic materials based on lithium disilicate for dental prosthetics is substantiated. The basic lithium silicate system was selected and glasses for obtaining glass-ceramic crowns based on lithium disilicate by the method of high-temperature pressing and calcium phosphate-silicate system for obtaining glass-ceramic coatings were synthesized.
 The methodological approach to the development of glass-ceramic prostheses based on lithium disilicate is determined. The limits of the compositions of oxide components are determined and raw materials for the synthesis of the glass matrix are selected. The technological parameters of melting (T = 1350 – 1400ºС) and heat treatment with simultaneous formation of products (stage of nucleation T = 600 – 650ºС, τ = 30 – 60 min; stages of formation T = 900ºС, τ ≈ 20 min) are selected. The composition of fluoroapatite glass-ceramic coating for glazing of glass-ceramics and the mode of its firing (T = 800 – 850ºС, τ ≈ 1,0 – 1,5 min) were determined. The serviceability of the developed glass-ceramic samples DL st.glass, which were obtained by the technology of high-temperature pressing, are determined.
 The comparative analysis of glass-ceramic prostheses for dentistry allowed to establish that the operational properties of the developed glass-ceramic prostheses according to ISO 6872:2015 are at the level of world analogues. This will allow them to successfully compete in the Ukrainian market with well-known foreign counterparts and help ensure the social priorities of the state in the field of health care.

FRET-based ‘ratiometric’ molecular switch for multiple ions with efficacy towards real-time sampling and logic gate applications

Fluorescent nanoaggregates comprised of rhodamine based amphiphilic probe has been designed, which can simultaneously detect Al 3+ , Cr 3+ and F¯ ions in the aqueous medium (pH 7.4). Mechanistic investigation indicates that both the carbonyl oxygen of the spirolactam ring and the nitrogen center of indole participate in the coordination of metal ions. Consequently, metal ion-binding induces the opening of the spirolactam ring and allows the Förster energy transfer from indole to xanthene moiety. As a result, the colorless probe solution turns pink in presence of metal ions, with ratiometric fluorescence change from blue to yellow. Further, the addition of fluoride leads to dissociation of preformed Al 3+ -complex, resulting in the fading of pink color and reverting the fluorescence signal to the original. This not only serves as a tool to discriminate between Al 3+ and Cr 3+ ion but also acts as a strategy for detecting fluoride in the aqueous medium. Thus, using a single FRET probe, ‘ratiometric’, naked-eye sensing of multiple ions was achieved. Also, considering the differential response of probe molecule towards Cr(III) and Cr(VI), a colorimetric assay for biogenic thiols was developed. Simultaneously, a combinatorial molecular logic gate was designed based on the multiple ion sensing ability of the probe molecule. Further, the system showed real-time detection of Al 3+ and Cr 3+ in natural water samples, estimation of Al 3+ in antacid tablets and fluoride in mouthwash, etc. Lastly, low-cost, reusable paper strips were developed, which offers an alternative strategy for on-site detection of metal ions without engaging any sophisticated instruments or trained personnel. • Ratiometric sensing of Al 3+ , Cr 3+ and F − ions at nanomolar levels in water. • Assay for biogenic thiols based on differential response for Cr(III) and Cr(VI). • Design combinatorial logic gate based on multiple ion sensing. • Analysis of real-life samples: fluoride in mouthwash, Aluminium in antacid tablets. • Low-cost, reusable paper strips for onsite detection of ions.

Dielectric and Piezoelectric Properties of 0.36BiScO<sub>3</sub> - 0.64PbTiO<sub>3</sub> Ceramic Doped with Calcium Fluoride

BiScO3-xPbTiO3 (BS-PT) of perovskite type structure (with x~0.64) were prepared by solid state ceramic process with addition of calcium fluoride (CaF2) in different molar ratios (0.5, 1.0 and 4.0 mol%). The doped compositions were found to have different symmetry compared with parent material. The 0.5 mol% doped sample was found to possess enhanced rhombohedral phase as compared to other compositions while he Curie temperature (Tc) was not affected appreciably. Small dielectric peaks were observed, indicating phase transition, at temperature lower than Tc in all the samples except 4.0% doped composition. At room temperature doping reduced the loss factor. d33 and Pr reduced rapidly with doping. The characteristics of BS-PT ferroelectric ceramics became harder with the addition of CaF2.

A fluorescent covalent triazine framework consisting of donor–acceptor structure for selective and sensitive sensing of Fe3+

A covalent triazine framework (FL-CTF) consisting of electron-donating thiophene units and electron-accepting benzothiadiazole units was synthesized using Suzuki polycondensation. The successful polymerization and chemical structure of FL-CTF were revealed by a combination of FTIR, solid-state 13C NMR, and XPS. The as-prepared FL-CTF with donor–acceptor structure shows fluorescence property in DMF. A series of fluorescent measurements were performed to ascertain the sensing property of FL-CTF toward metal ions. The fluorescence quenching appears upon addition of Fe3+ and the fluorescence intensity recovers facilely after the addition of a chelating agent tetrabutylammonium fluoride. To understand the fluorescence quenching and recovery process, UV–Vis absorption spectra and XPS were further measured. The electron transfer from FL-CTF to electron-deficient Fe3+ and the interaction between Fe3+ and nitrogen sites in FL-CTF may lead to fluorescence quenching. The interference experiments indicated that FL-CTF can selectively detect Fe3+ in the presence of other metal ions or different counter anions. Moreover, FL-CTF can detect Fe3+ with high sensitivity with the detection limit of 0.78 μM. These results demonstrate that FL-CTF has high selectivity and sensitivity toward Fe3+ and thus is expected to be a fluorescent sensor in practical applications.

Corrosion of NiCr Alloys for Dental Applications: Effects of Environment, Chemical Composition and Casting Route

The aim of this work is the assessment of the corrosion resistance of NiCr-based casting alloys in oral environments. The variables considered were the chemical composition of the source (raw) material, the casting process used and the characteristics of the environment. The following materials were tested: NiCrV (Ni70-77, Cr11-14, Mo3.5-8 wt.%), NiCrW (Ni59.6, Cr24, Mo9.8) and NiCrTi (Ni60-76, Cr12-21, Mo4-14, Ti4-6). Corrosion resistance was investigated by using electrochemical methods, and the corrosion morphology was determined by surface analysis techniques (SEM and optical stereoscopy). Results showed that the chemical composition of the source material was the determining factor for corrosion resistance, while the casting route and environment modification with fluoride addition did not affect the corrosion behavior of NiCr alloys. The corrosion morphology was localized exhibiting a peculiar dissolution pattern as observed in scanning droplet cell microscopy analysis. Furthermore, it was concluded that titanium segregation in the alloy after casting process was responsible for the lower localized corrosion resistance observed.

Fluorine-regulated surface chemical state of titanium dioxide (TiO

Environmental context As a new type of photocatalytic material, nano-titanium dioxide can be applied in the field of energy and environmental protection. This research uses ammonium bifluoride to modify the titanium dioxide and analyses it in combination with interface chemistry theory, and finds that its photocatalytic efficiency has been greatly improved. This provides new ideas for wastewater treatment and pollutant degradation. Abstract Titanium dioxide (TiO2) was prepared by hydrothermally adjusting titanium sulfate with ammonium hydrogen fluoride. The UV-visible absorption spectra show that there was no significant redshift in the absorption sideband of the sample, but the addition of ammonium hydrogen fluoride affected the morphology and microstructure of the sample. When the molar ratio of F to Ti was 1.5, the specific surface area of TiO2 more than doubled, the surface complexation mode changed significantly and the number of surface-active sites increased by a factor of 16.24. The photocatalytic degradation measurements show that the decolourisation rate of the photocatalyst prepared by fluorine control was increased by 40 % compared with the uncontrolled sample. The analysis of the combined state of the catalyst surface shows that the photocatalytic degradation efficiency and the amount of deprotonated TiO− as well as the number of positively charged oxidation states of methylene blue are clearly correlated. Furthermore, the number of active sites of the catalyst increased and the electrostatic interaction between fluorine and titanium formed a F-Ti dipole moment, which intensified the interaction between the negatively charged TiO− ion and the positively charged quinone methylene blue molecule. The lone pair electron of N in the quinone methylene blue molecule and the 3d orbital of Ti formed a metastable complex through coordination, and demethylation of the methylene blue molecules was completed.

Know the Basics of Water Fluoridation Measurement and Additive Products Safety

Adding fluoride to water is standard practice, but best practices for accurate measurement and safe handling of fluoride additives should be in place.

Addition of Phenylmethylsulfonyl Fluoride Increases the Working Lifetime of the Trout Liver S9 Substrate Depletion Assay, Resulting in Improved Detection of Low Intrinsic Clearance Rates.

The activity of a trout liver S9 substrate depletion assay has been shown to decline over time, presumably due to proteolytic degradation of biotransformation enzymes. To address this problem, assay performance was evaluated following the addition of phenylmethylsulfonyl fluoride (PMSF) or a general-purpose protease inhibitor cocktail to liver homogenization buffers and/or S9 reaction mixtures. Addition of PMSF to liver homogenization buffers and/or S9 reaction mixtures had little or no effect on clearance of phenanthrene, a model cytochrome P450 substrate, in short-term (25 or 30 min) depletion experiments but resulted in significant improvements in retention of this initial activity over time. The protease inhibitor cocktail strongly inhibited initial activity when added to homogenization buffers or reaction mixtures. Taking into consideration potential effects on liver carboxylesterases, the treatment approach determined to be optimal was addition of 10 µM PMSF to the S9 reaction mixture. Addition of 10 µM PMSF to the mixture resulted in significantly higher rates of phenanthrene clearance in 2-h incubations relative to those obtained in the absence of PMSF and a 6-fold increase in the working lifetime of the preparation. The results of a statistical power analysis suggest that by increasing the working lifetime of the assay, addition of PMSF to the reaction mixture could result in substantially improved detection of low in vitro clearance rates when compared to current practice. These findings demonstrate the value of adding PMSF to the trout S9 preparation and may have broad implications for use of this assay to support chemical bioaccumulation assessments for fish. Environ Toxicol Chem 2021;40:148-161. © 2020 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Effect of binary additives on performance of the undivided soluble-lead-redox-flow battery

Cycle-life of Soluble-Lead-Redox-Flow-Batteries (SLRFBs) is impacted due to formation of lead dendrites at anode and oxygen evolution at cathode. In this regard, addition of certain surfactants to the electrolyte helps preventing dendrite formation while adding fluoride salts reduces the rate of oxygen evolution reaction. Since SLRFB has a common electrolyte, understanding the combined effect of such additives on individual electrodes as well as on the overall SLRFB performance is desirable, which is lacking in the literature. Accordingly, in the present study, the combined effect of sodium lignosulfonate (SLS) and sodium fluoride (NaF) additives on the overall cell performance, individual electrodes, electrode kinetics, crystallographic phase formation, and surface morphology of electrodeposits is reported. The electrochemical data on SLRFB are analyzed in the light of electrode-kinetic parameters, namely limiting current-density, exchange current-density and Tafel-slope. The study reveals that adding NaF additive enhances the kinetics of Pb/Pb2+ and Pb2+/Pb4+ redox couples as compared to the pristine electrolyte or with SLS additive. The exchange current-density is higher with NaF additive as compared to NaF and SLS binary combined additive. It is also observed from cyclic voltammograms that the peak current decreases in the presence of binary additive indicating sluggish electrode kinetics. SEM images and galvanostatic charge–discharge studies suggest that binary additive results in uniform electrodeposit which improves the cycle-life of SLRFB.

Binder‐Assisted Dispersion of Agglomerated Carbon Nanotubes for Efficiently Establishing Conductive Networks in Cathodes of Li‐Ion Batteries

Carbon nanotubes (CNTs) are a promising conductive additive for Li‐ion batteries. However, good dispersion of agglomerated CNTs (ACNTs) still remains challenge. Herein, a binder‐assisted dispersion of ACNTs is demonstrated to efficiently construct a homogeneous conductive network in LiFePO4 cathodes. The addition of polyvinylidene fluoride (PVDF) significantly reduces the size of ACNT agglomerates, which leads to better dispersion of ACNTs in N‐methyl‐pyrrolidone. The LiFePO4 electrodes with conductive networks constructed from PVDF–ACNT suspensions exhibit superior electrode performance, as compared to those using the commercial CNT slurry.

Luminescence enhancement of high temperature hexagonal phase of Ba0.99MgAl10O17: Eu0.01 nanophosphor synthesized at moderately low temperature

Photoluminescent (PL) properties of Eu2+-doped BaMgAl10O17 (BAM:Eu2+) phosphors are significantly influenced by its crystallanity, phase and regular morphology. To obtain a high brightness blue-emitting BAM:Eu2+ nanophosphor, a pH-controlled polymeric gel deflagration method was performed at ~ 600 °C followed by post calcination at 1300 °C for 3 h under mild reducing atmosphere. It is one of the very few reports that depicts the formation of hexagonal phase of BAM:Eu2+ nanophosphor at relatively lower (~600 °C) temperatures, which is otherwise possible at very high (>1500 °C) sintering temperatures. A drastic improvement in crystallanity, phase, morphology and PL intensities has been achieved in BAM:Eu2+ nanophosphors with the addition of ammonium fluoride (NH4F) during post-calcination treatment. The presence of NH4F benefitted the thermal stability of BAM:Eu2+ nanophosphors as well. X-ray diffraction studies confirmed the phase purity while the scanning electron microscopy revealed regular morphology with non-aggregated nanoparticles. The improvement in crystallanity of BAM:Eu2+ nanophosphors led to almost four times increase in PL intensity in comparison to its bulk counterpart synthesized by solid-state reaction method. Intentional gamma irradiation of the samples for the creation of F+ centres is another unique feature studied in the current work. The obtained results clearly indicate that BAM:Eu2+ nanophosphor prepared in the study would be an ideal candidate for enhancing the properties of many active displays.

Fluorine-containing cast mica crystalline materials based on natural raw materials for lining magnesium electrolyzers

Refractory products traditionally used as structural elements or lining materials in electrolyzers, chlorinators and other magnesium production units do not provide sufficient performance. The most promising as a replacement for traditional materials are cast mica-crystalline refractory materials. However, their introduction into production is complicated by the need for expensive raw materials for their manufacture; the search for alternative raw materials is relevant. Studies show that a natural component, gabbrodolerite, with the addition of potassium fluoride in the amount of 100–200 thousandths of the total mass of the charge mixture can be used as a raw material for producing cast mica-crystalline materials intended to work as a lining of electrolyzers.

A portable logic detector based on Eu-MOF for multi-target, on-site, visual detection of Eu3+ and fluoride in groundwater

Developing a portable analytical device for rapid and visual detection of multiple targeted pollutants in groundwater is very important. In this paper, a novel Eu-MOF was prepared and applied for the highly sensitive and selective detection of Eu3+ and fluoride in groundwater. In the presence of Eu3+, the blue-violet fluorescence at 425 nm of Eu-MOF is greatly quenched because of the aggregation effect caused by Eu3+ combined with the amino functional groups exposed on Eu-MOF. The detection limit of Eu3+ has been determined as (2.481 ± 0.014) ×10−7 M according to the 3σ rule. Furthermore, the addition of fluoride would replace Eu3+ bound to amino group to induce the fluorescence recovery, and the detection limit of fluoride was calculated to be (1.145 ± 0.009) ×10-6 M. The common interfering ions have no influences on the selective detection of Eu3+ and fluoride by Eu-MOF. In addition, the spiked and recovery test indicated that Eu-MOF can be used for detection of Eu3+ and fluoride in real water samples and possess efficient and favorable practicability. More importantly, the logic detectors and paper sensors based on Eu-MOF were designed and fabricated as the portable analytical devices for the visual detection of Eu3+ and fluoride in groundwater. Our research would be beneficial and helpful for the water quality safety and human health guarantee.

High Quantum Efficiency of Er3+ ions in Phosphate Glasses: Controlled Atmosphere and Addition of Fluoride

In this work, we synthesized the phosphate glass pure and doped with erbium ions (Er3+) and investigated the effect of the controlled atmosphere and fluoride incorporation on the optical properties of Er3+ ions using the Judd-Ofelt theory. The PAN and PANK glass matrices with nominal compositions 60P205 - 10Al2O3 - 30Na2O (mol%) and 40P2O5 - 20Al2O3 - 35Na2O - 5K2O (mol%), pure and doped with Er2O3 and co-doped with LiF and CaF2, were synthesized by the fusion method in atmosphere in the air (NA) and controlled atmosphere (CA). The optical properties were investigated by optical absorption (AO), photoluminescence (PL) and temporal resolution photoluminescence (TRPL). The Judd-Ofelt theory was applied to determine the spectroscopic properties of Er3+ ions. The lifetime and quantum efficiency of the transition 4I13/2 → 4I15/2 were analyzed as a function of the atmosphere and addition of fluorides. The hydroxyl density (OH−) is determinant to the spectroscopic parameters of Er3+ inserted in the PAN and PANK glass matrices, and that it can be reduced both synthesized in CA and when adding LiF or CaF2. We found that the quantum efficiency of the transition4I13/2 → 4I15/2 was higher using the LiF doping methodology, and highest using together with CA, around 94%. Thus, the glass matrices synthesized with LiF and CA showed the best results. However, due to the high cost of synthesis using CA, we recommend only the use of fluorides in the matrices, since it presented close results. Interestingly, the PAN:Er matrix, which presented the worst optical results, with the incorporation of LiF and CA presented a quantum efficiency of 88% relatively high compared to other works in the literature.

Transition from 2D to 3D SBA-15 by High-Temperature Fluoride Addition and its Impact on the Surface Reactivity Probed by Isopropanol Conversion.

A systematic variation of the SBA‐15 synthesis conditions and their impact on the structural and chemical characteristics are reported. An incremental alteration of the hydrothermal aging temperature and time was used to induce changes of the highly ordered SBA‐15 structure. Any effects on the total surface area, mesopores size, micropore contributions, and pore connectivity are amplified by a combined incremental increase of the NH4F concentration. Based on changes of the unit‐cell parameter as a function of the mesopore size, and a feature in the low‐angle XRD pattern, useful descriptors for the disorder of the corresponding SBA‐15 are identified. An additional analysis of the Brunauer–Emmett–Teller (BET) surface area and pore size distributions enables investigations of the structural integrity of the material. This systematic approach allows the identification of coherencies between the evolution of physical SBA‐15 properties. The obtained correlations of the surface and structural characteristics allow the discrimination between highly ordered 2D SBA‐15, disordered 3D SBA‐15, and highly nonuniform silica fractions with mainly amorphous character. The fluoride‐induced disintegration of the silica structure under hydrothermal conditions was also verified by TEM. A direct influence of the structural adaption on the chemical properties of the surface was demonstrated by isopropanol conversion and H/D exchange monitored by FTIR analysis as sensitive probes for acid and redox active surface sites.

Intriguing ‘Turn-on’ phosphorescent response in the near infrared region upon fluoride binding: Dipyrromethene chelating-based Triarylboryl‒Iridium(III) conjugates

Two novel heteroleptic cyclometalated iridium(III) complexes, namely (C^N)2Ir(BL) (Ir1 and Ir2) (C^N = 2-(2,4-difluorophenyl)pyridine (dfphpy, for Ir1) and 2-phenylpyridine (phpy, for Ir2)), chelated by the triarylboryl dipyrromethene ancillary ligand (BL) were synthesized and characterized. The molecular structures of both complexes in the solid state were fully analyzed by single-crystal X-ray diffraction, and were found to be composed of Ir(III)-centered triarylborane conjugated systems. The UV–vis absorption spectra of both complexes displayed the typical 1MLCT (metal-to-ligand charge transfer) absorption bands centered at λabs = 483 nm, in addition to borane-centered CT absorption bands at ~326 nm. The photoluminescence (PL) spectra for these complexes demonstrated phosphorescent emission in the near infrared region (λem = ~690 nm), which was mainly attributed to the 3MLCT transition (L = BL). In addition, fluoride titration experiments using these complexes showed gradually quenched absorption bands in the region of 300–350 nm, corresponding to borane-centered CT transitions. Furthermore, 1H NMR experiments in THF-d8 for both complexes in the presence of fluoride sources revealed that the fluoride was bound to the dimesitylboryl moieties. Interestingly, upon the addition of fluoride, the PL spectra exhibited a ratiometrically ‘turn-on’ and gradually blue-shifted emissive response. Computational calculations and cyclic voltammetry measurements using the neutral Ir(III)-conjugates and their fluoride adducts strongly suggested that the intriguing emissive response is the result of fluoride binding interrupting the original 3MLCT transition, reinforcing the dipyrromethene-centered π–π* transition, and further inducing the enhancement of the band-gap.

Control of Photoisomerization of an Azoazacryptand by Anion Binding and Cucurbit[8]uril Encapsulation in an Aqueous Solution.

Control of isomerization of a receptor bearing multiple light-switchable subunits in a confined space is critical for the design of synthetic molecular machines. Toward this goal, a new azacryptand containing three azobenzene subunits has been developed, and its photoisomerization in an aqueous solution has been studied depending on anion coordination and recognition by a larger host-cucurbit[8]uril (CB[8]). The cryptand in its hexaprotonated form shows considerable affinity for fluoride and perchlorate, which in turn affects the isomer distribution of the receptor under UV-light irradiation, stabilizing the isomers of the cryptand with Z-configurations. CB[8] was found to be able to encapsulate the isomers of the cryptand by forming a Matryoshka-type complex. The irradiation of a 10:1 CB[8]-cryptand mixture has led to a selective conversion of the cryptand to the E,E,Z isomer inside CB[8]. It has been demonstrated that the addition of fluoride to the resulted complex induces the release of the cryptand as a major E,E,E isomer, while other studied anions were ineffective in this reaction. To our knowledge, this work presents a first example of a host-controlled photoisomerization of an anion receptor bearing multiple switching azobenzenes that model the function of naturally occurring chaperones.

DFT/TD‐DFT Based Study to Decipher the Proton Transfer Process in Anion Sensing Mechanism of NTS Molecule

AbstractIn the present work, we have performed DFT/TD‐DFT studies on NTS [1‐(((4‐(benzo[d]thiazol‐2‐yl) phenyl) imino) methyl) naphthalen‐2‐ol, referred to as 1E] to investigate the cyanide and fluoride anion sensing mechanism via proton transfer process in the ground and excited state. The potential energy curve for the proton transfer in ground (GSIPT) and excited state (ESIPT) suggests that, in case of NTS molecule, keto and enol form co‐exist. Based on the pattern of addition of cyanide on NTS, nucleophilic addition supports GSIPT rather ESIPT. However, fluoride addition showed both GSIPT and barrier less ESIPT processes followed by the deprotonation. From the energy calculations, we have observed that the cyanide addition (nucleophilic) block ICT character due to similar geometries in the ground and excited state, along with the interruption in the conjugation of the molecule. But, in the case of fluoride added product, ICT character was observed owing to the change in geometry of the corresponding states (ground and excited). ESIPT process has also been explained in terms of HOMO‐LUMO electron density, potential energy surfaces and NBO analysis.

EFFECTIVENESSOF CASEIN PHOSPOPEPTIDE AMORMPHOUS CALCIUM PHOSPHATE WITH OR WITHOUT FLUORIDE ON REMINELIZATION OF ENAMEL CARIES- LIKE LESIONS IN PRIMARY TEETH

Abstract: Objective: To evaluate and compare the remineralization effect of casein phospho-peptide amorphous calcium phosphate with or without fluoride “MI paste”&“MI Paste Plus” respectively” on the re-mineralization of enamel caries-like lesions in primary teeth. Material and methods: Artificial caries lesion was made on the labial surface of 40 extracted or exfoliated sound primary teeth which were then divided into 2 halves; one half was treated with one of the tested remineralizing agent “MI paste” or “MI Paste Plus”” while the other half served as a control. The lesions were evaluated both qualitatively using a polarized light microscope and quantitatively by measuring “calcium and phosphate” content using “energy-dispersive X-ray spectroscopy”. Data were collected and analyzed by using paired t-test to compare the control and the study groups for each material, while the “t-test” was used to compare between the two study groups. Results: Both “MI paste” and “MI Paste Plus” showed significant re-mineralization to the subsurface enamel lesions. “MI Paste Plus” showed significantly better results than “MI paste” with an increased amount of calcium “t=5.59 p=<0.0001”, Ca/phosphate ratio “t=4.08 p=0.003” and reduction in the amount of phosphate content “t=4.57 p= 0.001”. Conclusion: Both “MI paste” and “MI Paste Plus” were effective in enamel remineralization, the addition of fluoride in “MI Paste Plus” acted synergistically with the casein phospho-peptide amorphous calcium phosphate and gave better remineralization effect on enamel.