Ugradnja Lantanida u caklinu ljudskih zuba

The incorporation of lanthanides in human dental enamel was investigated by means o f X-ray microprobe analysis. Sound human premolar teeth - after extraction-were prepared and kept for 60 days in 10% solutions of neodymium-, samariumeuropium-, ytterbium resp. lanthanum-chloride at room temperature with constant shaking. Results of the X-ray microprobe analysis revealed 100-140 m depth penetration and incorporation o f neodymium, with transformation o f the apatite phases of enamel into neodymium-hydroxil-apatite-, resp. neodymium- hidrochlor-apatite. The changes were accompanied by a decrease in the values o f calcium, magnesium and sodium. Samarium- , ytterbium-, europium and lanthanum-chloride treatments produced a phosphate-complex containing coherent layer on the enamel surface. However, no real incorporation into the apatite-lattice was observed. The incorporation o f neodymium-apatites, and the formation of cerium-apatite into the dental enamel observed in previous studies might indicate the possibility of stabilizing the apatite structure, and discovering new ways of caries prevention.U radu je istraživana ugradnja lantanida u humanu caklinu zuba s pom oću rendgenske mikroanalize.Zdravi ljudski prem olari su poslije vađenja priprem ljeni i držani kroz 60 dana u 10% otopinama neodijsamarij, iterbij i lantanij klorida na sobnoj tem peraturi uz trajno m iješanje. Rezultati rendgenske m ikroanalize objelodanili su i potvrdili prodor i ugradnju neodija, s preobrazbom apatita cakline u neodij - -hidroxil-apatit. Promjene su bile praćene smanjenjem vrijednosti kalcija, magnezija i kalija. Samarij, iterbij, europij i lantanij klorid u postupku su uzrokovali stvaranje kompleksa fosfata stvarajući čvrst sloj na caklinskoj površini. M eđutim, prava ugradnja u caklinsku strukturu nije primijećena. Inkorporacija neodij apatita i stvaranje cerij apatita, što je bilo prim ijećeno u prethodnim studijama, moglo bi ukazivati na mogućnost stabilizacija apatitne strukture i otkriće novih putova prevencije karijesa

Effect of fluoride toothpastes on enamel demineralization

BACKGROUND: It was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization. METHODS: A 3 × 3 mm window on the enamel surface of 90 human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 6 groups and the lower half of the window was covered with varnish serving as control. The teeth were immersed in a toothpaste slurry containing: placebo tooth paste (group 1); remineralization solution (group 2); Elmex Anticaries (group 3); Elmex Sensitive (group 4); Blend-a-med Complete (group 5) and Colgate GRF (group 6). Ten teeth of each group were used for the determination of the F(- )content in the superficial enamel layer and acid solubility of enamel expressed in soluble phosphorus. Of 6 teeth of each group serial sections were cut and investigated with polarization light microscopy (PLM) and quantitative energy dispersive X-ray analysis (EDX). RESULTS: The PLM results showed an increased remineralization of the lesion body in the Elmex Anticaries, Elmex Sensitive and Colgate GRF group but not in the Blend-a-med group. A statistically significant higher Ca content was found in the Elmex Anticaries group. The fluoride content in the superficial enamel layer was significantly increased in both Elmex groups and the Blend-a-med group. Phosphorus solubility was significantly decreased in both Elmex groups and the Blend-a-med group. CONCLUSION: It can be concluded that amine fluoride compounds in toothpastes result in a clearly marked remineralization of caries like enamel lesions followed by sodium fluoride and sodium monofluorophosphate formulations

Effect of pH of amine fluoride containing toothpastes on enamel remineralization in vitro

<p>Abstract</p> <p>Background</p> <p>One of the important factors of the demineralization and remineralization equilibrium of enamel is the pH of the surrounding solutions. Effort has been laid in the formulation of different fluoride compounds and the fluoride content in toothpastes but much less is known about the influence of the pH of the toothpastes on their effectiveness. It was therefore the aim of this study to investigate the influence of different pH levels on enamel remineralization in an in vitro experiment using polarization light microscopy and EDX quantitative element analysis.</p> <p>Methods</p> <p>A 5 × 5 mm window on the enamel surface of 40 caries free extracted human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 8 groups and the lower half of the window was covered with varnish serving as control. Each group was then immersed in toothpaste slurry containing amine fluoride (1400 ppm) at pH 4.1, 4.5, 5.1 and 6.9 or control toothpaste slurry without fluoride at pH 4.3, 4.7, 5.3 and 7.0. Serial sections were cut through the lesions and investigated with polarization light microscopy and quantitative EDX element analysis.</p> <p>Results</p> <p>The PLM results showed a decreased porous volume of the body of the lesion after incubation with fluoridated toothpaste at pH 4.53 and 5.16. No differences between the experimental window and the control window were found in the other groups. The quantitative element analysis showed no differences in the element content of any of the groups.</p> <p>Conclusion</p> <p>From the results it can be concluded that slightly acidified fluoridated dentifrices may have a certain positive effect on enamel remineralization.</p

Ugradnja Lantanida u caklinu ljudskih zuba

The incorporation of lanthanides in human dental enamel was investigated by means o f X-ray microprobe analysis. Sound human premolar teeth - after extraction-were prepared and kept for 60 days in 10% solutions of neodymium-, samariumeuropium-, ytterbium resp. lanthanum-chloride at room temperature with constant shaking. Results of the X-ray microprobe analysis revealed 100-140 m depth penetration and incorporation o f neodymium, with transformation o f the apatite phases of enamel into neodymium-hydroxil-apatite-, resp. neodymium- hidrochlor-apatite. The changes were accompanied by a decrease in the values o f calcium, magnesium and sodium. Samarium- , ytterbium-, europium and lanthanum-chloride treatments produced a phosphate-complex containing coherent layer on the enamel surface. However, no real incorporation into the apatite-lattice was observed. The incorporation o f neodymium-apatites, and the formation of cerium-apatite into the dental enamel observed in previous studies might indicate the possibility of stabilizing the apatite structure, and discovering new ways of caries prevention.U radu je istraživana ugradnja lantanida u humanu caklinu zuba s pom oću rendgenske mikroanalize.Zdravi ljudski prem olari su poslije vađenja priprem ljeni i držani kroz 60 dana u 10% otopinama neodijsamarij, iterbij i lantanij klorida na sobnoj tem peraturi uz trajno m iješanje. Rezultati rendgenske m ikroanalize objelodanili su i potvrdili prodor i ugradnju neodija, s preobrazbom apatita cakline u neodij - -hidroxil-apatit. Promjene su bile praćene smanjenjem vrijednosti kalcija, magnezija i kalija. Samarij, iterbij, europij i lantanij klorid u postupku su uzrokovali stvaranje kompleksa fosfata stvarajući čvrst sloj na caklinskoj površini. M eđutim, prava ugradnja u caklinsku strukturu nije primijećena. Inkorporacija neodij apatita i stvaranje cerij apatita, što je bilo prim ijećeno u prethodnim studijama, moglo bi ukazivati na mogućnost stabilizacija apatitne strukture i otkriće novih putova prevencije karijesa

Effect of fluoride on cariogenic oral microorganisms

The effect of sodium fluoride and sodium monofluorophosphate at concentrations of 1, 5, 10, 50, 100 and 1000 mg/l in phosphate buffer (pH 6.5) as well as in UHT milk were studied on cultures and suspensions of Streptococcus mutans, Lactobacillus acidophilus and Candida albicans. Using serial tenfold dilutions up to 10-7 of 24-48 hour cultures, a subsequent 0, 60 and 120 min incubation caused no decrease in the number of CFUs. Growth kinetic studies in the Bioscreen biophotometer (Labsystem, Finland) revealed that sodium fluoride in different concentrations (from 0.875 mg/l up to 500 mg/l) influenced the growth dynamics of S. mutans and C. albicans: the exponential phase flattened out at the highest fluoride concentrations (500 mg/l) present in the growth media. The lag phase of C. albicans became longer. The results of these experiments indicate that sodium fluoride administered at higher concentrations than the usual caries preventive dosage made the generation time of cariogenic oral bacteria and fungi longer, slowing down their multiplication

Physics and technology of the Next Linear Collider: a report submitted to Snowmass '96

We present the current expectations for the design and physics program of an e+e- linear collider of center of mass energy 500 GeV -- 1 TeV. We review the experiments that would be carried out at this facility and demonstrate its key role in exploring physics beyond the Standard Model over the full range of theoretical possibilities. We then show the feasibility of constructing this machine, by reviewing the current status of linear collider technology and by presenting a precis of our `zeroth-order' design