Reduction of Intra-oral Demineralization of Enamel after Single Exposures to Sodium Fluoride

1992 ◽  
Vol 71 (3_suppl) ◽  
pp. 867-870 ◽  
Author(s):  
S. Kashket ◽  
L.R. Lopez
Keyword(s):  
Protective Effect ◽  
Streptococcus Mutans ◽  
Sodium Fluoride ◽  
Experimental Period ◽  
Low Concentrations ◽  
Baseline Values ◽  
Two Stages ◽  
Bovine Enamel ◽  
Mineral Loss ◽  
Initial Elevation

Studies demonstrated the effects of single rinses with low concentrations of NaF on the intra-oral demineralization of enamel. Blocks of bovine enamel were covered with Streptococcus mutans IB1600, mounted in palatal appliances, and worn in the mouths of volunteers for specified times. Subjects rinsed with solutions of NaF, with or without sucrose. Demineralization was determined as changes in iodide penetrability (delta Ip) of the enamel, while the pH and F of the streptococcal plaque, and enamel F, were determined with ion-specific electrodes. Delta Ip was reduced by about 80% (from 14.5 ± 2.7 to 2.8 ± 2.3 units) when 250 μg F/mL was added to the sucrose rinse. Corresponding plaque pH's were 4.1 ± 0.5 and 4.2 ± 0.3, consistent with a lack of effect on bacterial acidogenesis. Protection against mineral loss was concentration-dependent. Administration of sucrose at different times after NaF revealed that the effect of F persisted for at least 60 min. Analyses of plaque F demonstrated an initial elevation and concentration within the cells, followed by a drop to stable, baseline values. Enamel F increased slowly to almost 500 μg/g enamel after 105 min. The protective effect of F appeared to be manifested in two stages, the first related to a high plaque F and the second to F that became incorporated into the enamel. Analysis of the data suggested that F was transferred from plaque to enamel during the experimental period.

Cariostatic Activity of (1,6-Bis-[2-Ethylhexylbiguanido]-Hexane) in Conventional Rats

1979 ◽  
Vol 58 (4) ◽  
pp. 1405-1412 ◽  
Author(s):  
Stephen N. Curtis ◽  
Claire L. Dooley
Keyword(s):  
Drinking Water ◽  
Oral Cavity ◽  
Streptococcus Mutans ◽  
Sodium Fluoride ◽  
Progressive Increase ◽  
Continuous Administration ◽  
Low Concentrations ◽  
Very High

The antimicrobial and cariostatic activities of the dihydrochloride and dihydrofluoride salts of alexidine (1, 6-bis-[2-ethylhexylbiguanido]hexane) were compared to those of chlorhexidine acetate and sodium fluoride in rats implanted orally with Streptococcus mutans 6715 and fed a cariogenic diet. Experimental caries was significantly reduced by the continuous administration of low concentrations of biguanides via the drinking water, but this was accompanied by increased staining of the molars. Very high biguanide concentrations, applied infrequently, directly to the molars, effectively reduced caries and resulted in less staining. A combination of alexidine dihydrochloride and sodium fluoride offered no advantage over either drug alone. Alexidine salts prevented the progressive increase in implanted S. mutans, whereas chlorhexidine acetate practically eliminated the microorganism from the oral cavity. Sodium fluoride had no effect on the implanted flora. It was concluded that alexidine salts are comparable in cariostatic activity to chlorhexidine. The tooth staining accompanying the use of bisbiguanides can be reduced by adjusting the concentration of the drug and its frequency of application.

Inhibition of Streptococcus mutans Growth and Biofilm Formation by Probiotics in vitro

2017 ◽  
Vol 51 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Falk Schwendicke ◽  
Franziska Korte ◽  
Christof E. Dörfer ◽  
Susanne Kneist ◽  
Karim Fawzy El-Sayed ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Mixed Species ◽  
Displacement Mode ◽  
Probiotic Strains ◽  
Culture Growth ◽  
Bovine Enamel ◽  
Mineral Loss

To exert anticaries effects, probiotics are described to inhibit growth and biofilm formation of cariogenic bacteria such as Streptococcus mutans (SM). We screened 8 probiotics and assessed how SM growth or biofilm formation inhibition affects cariogenicity of probiotic-SM mixed-species biofilms in vitro. Growth inhibition was assessed by cocultivating probiotics and 2 SM strains (ATCC 20532/25175) on agar. Probiotics were either precultured before SM cultivation (exclusion), or SM precultured prior to probiotic cultivation (displacement). Inhibition of SM culture growth was assessed visually. Inhibition of SM biofilm formation on bovine enamel was assessed using a continuous-flow short-term biofilm model, again in exclusion or displacement mode. The cariogenicity of mixed-species biofilms of SM with the most promising growth and biofilm formation inhibiting probiotic strains was assessed using an artificial mouth model, and enamel mineral loss (ΔZ) was measured microradiographically. We found limited differences in SM growth inhibition in exclusion versus displacement mode, and in inhibition of SM 20532 versus 25175. Results were therefore pooled. Lactobacillus acidophilus LA-5 inhibited significantly more SM culture growth than most other probiotics. L. casei LC-11 inhibited SM biofilm formation similarly to other alternatives but showed the highest retention of probiotics in the biofilms (p < 0.05). Mineral loss from SM monospecies biofilms (ΔZ = 9,772, 25th/75th percentiles: 6,277/13,558 vol% × µm) was significantly lower than from mixed-species SM × LA-5 biofilms (ΔZ = 24,578, 25th/75th percentiles: 19,081/28,768 vol% × µm; p < 0.01) but significantly higher than from SM × LC-11 biofilms (ΔZ = 4,835, 25th/75th percentiles: 263/7,865 vol% × µm; p < 0.05). Probiotics inhibiting SM culture growth do not necessarily reduce the cariogenicity of SM-probiotic biofilms. Nevertheless, SM biofilm formation inhibition may be relevant in the reduction of cariogenicity.

scholarly journals Caries infiltrant combined with conventional adhesives for sealing sound enamel in vitro

2013 ◽  
Vol 83 (5) ◽  
pp. 858-863 ◽  
Author(s):  
Enver Yetkiner ◽  
Florian Just Wegehaupt ◽  
Rengin Attin ◽  
Thomas Attin
Keyword(s):  
Protective Effect ◽  
In Vitro Study ◽  
Negative Control ◽  
Protective Measures ◽  
Low Viscosity ◽  
Monomer Content ◽  
Bovine Enamel ◽  
Mineral Loss ◽  
Better Than

ABSTRACT Objective: To test the null hypothesis that combining low-viscosity caries infiltrant with conventional adhesive resins would not improve sealing of sound enamel against demineralization in vitro. Materials and Methods: Bovine enamel discs (N  =  60) with diameter of 3 mm were randomly assigned to six groups (n  =  10). The discs were etched with 37% phosphoric acid for 30 seconds and treated with resins of different monomer content forming the following groups: (1) Icon (DMG), (2) Transbond XT Primer (3M ESPE), (3) Heliobond (Ivoclar Vivadent), (4) Icon + Transbond XT Primer, and (5) Icon + Heliobond. Untreated etched samples served as the negative control. Specimens were subjected to demineralization by immersion in hydrochloric acid (pH 2.6) for 80 hours. Calcium dissolution into the acid was assessed by colorimetric analysis using Arsenazo III method at 16-hour intervals. Groups presenting high protection against demineralization were subjected to further acidic challenge for 15 days with calcium measurements repeated at 24-hour intervals. Data were analyzed by Kruskal-Wallis test and Mann-Whitney U-test. Results: Untreated specimens showed the highest amount of demineralization. Icon and Transbond XT primer decreased the mineral loss significantly compared to the control. Heliobond performed significantly better than both Icon and Transbond XT primer. Combination of Icon both with Transbond XT primer or Heliobond served as the best protective measures and maintained the protective effect for the additional 15-day acidic challenge. Conclusions: Within the limitations of this in vitro study, it could be concluded that the use of low-viscosity caries infiltrant prior to application of the tested conventional adhesives increases their protective effect against demineralization.

In situ Effect of Frequent Sucrose Exposure on Enamel Demineralization and on Plaque Composition after APF Application and F Dentifrice Use

2004 ◽  
Vol 83 (1) ◽  
pp. 71-75 ◽  
Author(s):  
A.F. Paes Leme ◽  
R. Dalcico ◽  
C.P.M. Tabchoury ◽  
A.A. Del Bel Cury ◽  
P.L. Rosalen ◽  
...  
Keyword(s):  
Sucrose Solution ◽  
Experimental Period ◽  
Mutans Streptococci ◽  
Plaque Composition ◽  
Treatment Groups ◽  
Enamel Demineralization ◽  
Combination Of Methods ◽  
Bovine Enamel ◽  
Mineral Loss

Since the effect of the combination of methods of fluoride use on enamel demineralization and on plaque composition is not clearly established, this study examined the effect of the combination of acidulated phosphate fluoride (APF) application and F dentifrice on enamel demineralization and on plaque composition. In this crossover study, 16 volunteers, wearing a palatal appliance containing bovine enamel blocks, were subjected to 4 treatment groups: non-fluoridated dentifrice (PD), FD, APF+PD, and APF+FD. The APF was applied to the enamel before the 14-day experimental period. During the experimental period, test dentifrices were applied 3×/day, and a 20% sucrose solution was applied 4× and 8×/day by being dripped on the blocks. Although APF application was able either to increase F concentration in plaque or to reduce the % of mutans streptococci, its combination with F dentifrice use neither reduced enamel mineral loss nor changed any other measured plaque variable with respect to the FD group alone.

scholarly journals Effect of Pseudomonas moorei KB4 Cells’ Immobilisation on Their Degradation Potential and Tolerance towards Paracetamol

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 820
Author(s):  
Robert Surma ◽  
Danuta Wojcieszyńska ◽  
Jagna Karcz ◽  
Urszula Guzik
Keyword(s):  
Protective Effect ◽  
Kinetic Parameters ◽  
Toxicity Assessment ◽  
Bacterial Cells ◽  
Low Concentrations ◽  
Toxicity Analysis ◽  
Immobilised Cells ◽  
Degradation Activity ◽  
High Concentrations ◽  
The Hill

Pseudomonas moorei KB4 is capable of degrading paracetamol, but high concentrations of this drug may cause an accumulation of toxic metabolites. It is known that immobilisation can have a protective effect on bacterial cells; therefore, the toxicity and degradation rate of paracetamol by the immobilised strain KB4 were assessed. Strain KB4 was immobilised on a plant sponge. A toxicity assessment was performed by measuring the concentration of ATP using the colony-forming unit (CFU) method. The kinetic parameters of paracetamol degradation were estimated using the Hill equation. Toxicity analysis showed a protective effect of the carrier at low concentrations of paracetamol. Moreover, a pronounced phenomenon of hormesis was observed in the immobilised systems. The obtained kinetic parameters and the course of the kinetic curves clearly indicate a decrease in the degradation activity of cells after their immobilisation. There was a delay in degradation in the systems with free cells without glucose and immobilised cells with glucose. However, it was demonstrated that the immobilised systems can degrade at least ten succeeding cycles of 20 mg/L paracetamol degradation. The obtained results indicate that the immobilised strain may become a useful tool in the process of paracetamol degradation.

Serum Cholinesterase Variants: Examination of Several Differential Inhibitors, Salts, and Buffers Used to Measure Enzyme Activity

1971 ◽  
Vol 17 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Philip J Garry
Keyword(s):  
Enzyme Activity ◽  
Sodium Fluoride ◽  
Phosphate Buffer ◽  
Divalent Cations ◽  
Kinetic Studies ◽  
Competitive Inhibitor ◽  
Serum Cholinesterase ◽  
Low Concentrations

Abstract Dibucaine, used as a differential inhibitor with acetyl-, propionyl-, and butyrylthiocholine as substrate, clearly identified the "usual" and "atypical" serum cholinesterases. Succinylcholine was also used successfully as a differential inhibitor with butyrylthiocholine as substrate. Sodium fluoride, used as a differential inhibitor, gave conflicting results, depending on whether Tris or phosphate buffer was used in the assay. Mono- and divalent cations (NaCl, KCl, MgCl2, CaCl2, and BaCl2) activated the "usual" and inhibited the "atypical" enzyme at low concentrations. The "usual" enzyme had the same activity in 0.05 mol of Tris or phosphate buffer per liter, while the heterozygous and "atypical" enzymes showed 12 and 42% inhibition, respectively, when assayed in the phosphate buffer. Kinetic studies showed the phosphate acted as a competitive inhibitor of "atypical" enzyme. Km values, determined for "usual" and "atypical" enzymes, were 0.057 and 0.226 mmol/liter, respectively, with butyrylthiocholine as substrate.

Protective Effect of Solutions Containing Polymers Associated with Fluoride and Stannous Chloride on Hydroxyapatite Dissolution

2021 ◽  
pp. 1-8
Author(s):  
Marina Gullo Augusto ◽  
Tamires Maria de Andrade Santos ◽  
Taís Scaramucci ◽  
Idalina Vieira Aoki ◽  
Carlos Rocha Gomes Torres ◽  
...  
Keyword(s):  
Protective Effect ◽  
Sodium Fluoride ◽  
Stannous Chloride ◽  
Deionized Water ◽  
Lower Amount ◽  
Citric Acid Solution ◽  
Solution Ph ◽  
Methacrylate Copolymer ◽  
Total Reaction Time ◽  
Hydroxyapatite Crystals

This study investigated the protective effect of experimental solutions containing 4 polymers (polyoxirane, hydroxypropylmethylcellulose [HPMC], pectin, and an amino methacrylate copolymer [AMC]) in 2 concentrations (low and high) associated or not with sodium fluoride (F; 225 ppm F<sup>–</sup>) or sodium fluoride plus stannous chloride (FS; 800 ppm Sn<sup>2+</sup>) on the dissolution of hydroxyapatite crystals (HA). Deionized water was the control. The pretreated HA was added to a 0.3% citric acid solution (pH 3.8). An automatic titrant machine added aliquots of 0.1 N HCl at a rate of 28 μL/min, in a total reaction time of 5 min. Groups were compared with 2-way ANOVA and Tukey’s test, and concentrations with Student <i>t</i> test (5%). The zeta potential of the HA treated with the solutions was measured. Significant differences were found for both factors and interaction (<i>p</i> &#x3c; 0.0001). The treatments with F and FS solutions resulted in a lower amount of dissolved HA than the control. Among the polymers’ solutions, only AMC was able to reduce the amount of dissolved HA, changing the surface charge of HA to positive. AMC improved the protective effect of F, but it did not affect FS. Polyoxirane and HPMC reduced the protective potential of the FS solution. No differences were found between the concentrations of the polymers. It was concluded that F and FS reduced the amount of dissolved HA. The protective effect of the experimental solutions against HA dissolution was polymer dependent. The F effect was enhanced by its combination with AMC, but the protection of FS was impaired by polyoxirane and HPMC.

scholarly journals Sodium fluoride as an ascaricide for swine raised on the ground

1969 ◽  
Vol 31 (2) ◽  
pp. 190-202
Author(s):  
Radamee Orlandi ◽  
Fernando E. Armstrong
Keyword(s):  
Sodium Fluoride ◽  
Ascaris Lumbricoides ◽  
Experimental Period ◽  
Growing Pigs ◽  
Control Group ◽  
Repeated Treatment ◽  
Treatment Trial ◽  
Cent Sodium ◽  
Group A ◽  
Group B

Two trials were conducted to test the value of sodium fluoride as an ascaricide for growing pigs kept on infested grounds. The ability of the drug to kep animals free from ascarides and the possible toxicity upon repeated treatment were also studied. Three groups of animals similar as to breeding, weight and age were used in Trial I. Group "A" served as control. Group "B" received 0.2 gm. of phenothiazine per pound or bodily weight and group "C" one per cent sodium fluoride mixed with ground feed. Except for slight variations in the procedure and the elimination of the phenothiazine treatment, Trial II was conducted in the same manner. The effectiveness of the different treatments given during the experimental period was measured by statistical analyses of the number of ascarid and non-ascarid eggs per gram of fresh rectal feces secured once every week, by the weight gains made by each animal, and by the number of Ascaris worms found upon visceral examination. The results obtained suggest that sodium fluoride at the rate of one per cent mixed in the feed every three weeks is a very satisfactory drug for killing Ascaris lumbricoides suis found in growing pigs raised on the ground. When fed repeatedly to growing pigs for periods of from 3 to 4 months it was effective in keeping the animals clean, with no toxic effects whatsoever. Phenothiazine at the rate of 0.2 gm. per pound of bodily weight administered every three weeks was found to be unreliable as an ascaricide. The data obtained during the two trials made suggest that sodium fluoride is specific against Ascaris lumbricoides suis.

scholarly journals Comparison of the activity and conformation changes of lactate dehydrogenase H4 during denaturation by guanidinium chloride

1991 ◽  
Vol 277 (1) ◽  
pp. 207-211 ◽  
Author(s):  
Y Z Ma ◽  
C L Tsou
Keyword(s):  
Lactate Dehydrogenase ◽  
Active Site ◽  
Cross Linking ◽  
Native Conformation ◽  
Guanidinium Chloride ◽  
Original Activity ◽  
Limited Region ◽  
Low Concentrations ◽  
Two Stages ◽  
Inhibited Enzyme

The inactivation and unfolding of lactate dehydrogenase (LDH) during denaturation by guanidinium chloride (GuHCl) under diverse conditions have been compared. Unfolding of the native conformation, as monitored by fluorescence and c.d. measurements, occurs in two stages with increasing GuHCl concentrations, and the inactivation approximately coincides with, but slightly precedes, the first stage of unfolding. The enzyme is inhibited to about 60-70% of its original activity by cross-linking with glutaraldehyde or in the presence of 1 M-(NH4)2SO4, with its conformation stabilized as shown by the requirement for higher GuHCl concentrations to bring about both inactivation and unfolding. Low concentrations of GuHCl (0.2-0.4 M) activate the cross-linked and the (NH4)2SO4-inhibited enzyme back to the level of the native enzyme. For the enzyme stabilized by (NH4)2SO4 or by cross-linking with glutaraldehyde, inactivation occurs at a markedly lower GuHCl concentration than that required to bring about its first stage of unfolding. It is concluded that the active site of LDH is situated in a limited region relatively fragile in conformation as compared with the molecule as a whole. The GuHCl activation of LDH stabilized in (NH4)2SO4 or by cross-linking with glutaraldehyde suggests that this fragility and consequently flexibility of the active site is required for its catalytic activity.

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