Search PubMed⌕ Search

Biomedical subjects

I Gedalia

Publications and source records attributed to I Gedalia.

At least 55 records · Page 3Linked to original sources
PubMed1985

Iron uptake by teeth and bones: a Mossbauer effect study.

Iron uptake (Fe2+ and Fe3+) by bones, teeth, and dental enamel was studied, in vivo and in vitro, by chemical, powder X-ray diffraction and Mossbauer spectroscopy methods. Atomic absorption tests have revealed the permanent uptake of small amounts of iron by dental enamel soaked in vitro in solutions containing Fe2+. Mossbauer spectra show that the iron attached to the dental enamel stays at the same valency it had in the soaking solutions. Mossbauer measurements of in vivo samples show that iron is present in bones and teeth mainly as Fe3+ (10% Fe2+ in teeth), in compound similar to FeOOH. Iron is released or exchanged from teeth at a much lower rate than from bones.

Animals↗
PubMed1985

Tooth wear, solubility and fluoride concentration of molar-tooth surfaces in rats maintained on simultaneous or separate intake of food and fluoridated drinking water.

Eighty rats, 20 days old, were fed a hard pellet diet and deionized or fluoridated (25 parts/10(6) F-) drinking water respectively for 40 days. Half were maintained on simultaneous food and water intake for 3 h, daily, and the remainder on separate intake of food for 3 h followed by drinking water for 3 h, daily. Scanning electron micrographs of the occlusal surface of right maxillary first molars were used for scoring wear. The mandibular and left maxillary molar surfaces were used for solubility and fluoride concentration determinations. Intake of food and water separately did not affect wear significantly, whereas solubility and fluoride concentration of the molar surfaces were significantly increased. Wear, solubility and fluoride of the molar surfaces respectively were highly significantly increased in the rats provided with fluoridated water. Increase in fluoride uptake is due in part at least to the increase in sites available for uptake due to tooth wear. Acid dissolution of worn tooth-surface enamel is greater than that of intact enamel.

Animals↗
PubMed1985

The effect of iron on in vitro decalcification of human tooth enamel.

The effect of iron chloride on an in vitro acid attack of human enamel was studied. Slices of teeth were covered with varnish except for a window left on one of the enamel surfaces for exposure. The iron salt was used as a supplement to acid gel, or as pretreatment of the enamel surfaces before exposure to the pure gel. Differences in light transmission of the experimental and control specimen from the radiographs taken before and after immersion in the decalcifying media were assessed quantitatively. The increase in radio-opacity of the enamel sections incubated in the iron-containing acid media was attributed to a lower degree of enamel decalcification.

Acids↗
PubMed1984

Fluoride enhancement of chlorhexidine uptake by hydroxyapatite and enamel powders.

The purpose of the present study was to examine the in vitro adsorption of chlorhexidine and fluoride to hydroxyapatite and tooth enamel powders. Samples of hydroxyapatite or enamel powder were suspended in aqueous solutions of chlorhexidine gluconate 2.0; chlorhexidine acetate 1.5%; sodium fluoride of various concentrations (0.2%, 1%, 2%) and mixtures of sodium fluoride and chlorhexidine. The data obtained in the study show that chlorhexidine and fluoride adsorb to hydroxyapatite and tooth enamel in vitro. Furthermore, the amount of fluoride adsorbed to hydroxyapatite is reduced in the presence of chlorhexidine in the solution. A probable explanation for this effect may be that there is a competitive adsorption of fluoride and chlorhexidine on to the same binding sites on the hydroxyapatite. Additionally, the presence of fluoride dramatically increases the affinity of chlorhexidine for hydroxyapatite. The fact that fluoride strongly enhanced the adsorption of chlorhexidine to hydroxyapatite and enamel, indicates that fluoride may be of clinical interest beyond the prevention of caries.

Adsorption↗
PubMed1984

Enamel dissolution and fluoride uptake from sugar solutions.

Solubility studies and fluoride uptake by enamel powder in xylitol-buffered solutions versus sucrose- and glucose-buffered solutions were carried out. The studies were done at a pH range of 4-8. The enamel solubility in the xylitol media was similar to the enamel solubility in the other sugar solutions--increasing with a decreasing pH. The solubility of enamel in the buffered sugar solutions was significantly lower as compared to the solubility in the sugar-free buffered solutions--up to the pH of 6. At the pH values of 7 and 8 the amounts of solubility were similar for the experimental and control solutions. No significant differences were found in the fluoride uptake by the enamel powder from the fluoride-containing sugar solutions at the pH values of 6 and 7.5 respectively. The results point to the conclusion that the xylitol does not differ from sucrose and glucose in its effect on enamel powder solubility and the uptake of fluoride ions by enamel.

Carbohydrate Metabolism↗
PubMed1984

Changes in size, morphology and weight of human anterior teeth during the fetal period.

The changes in size and weight of the calcified portions of the crowns of deciduous anterior teeth (maxillary and mandibular central and lateral incisors and canines) in human fetuses aged 5-10 months were studied. Relating the weight and size of each tooth to fetal age provided quantitative information on the rate of crown development in each of these teeth. There is a good correlation between crown height and fetal age. At the corresponding ages the length of the maxillary central incisor is greater than that of the maxillary lateral incisor which is greater than that of the maxillary canine. A similar pattern is found in the mandibular teeth. Generally, with the exception of a few mandibular central incisors, no type of anterior tooth crown has reached its final length before birth.

Female↗
PubMed1982

Fluoride deposition in the bones of rats determined by fluoride and X-ray diffraction analysis.

Rats were given drinking water containing up to 300 parts/10(6) F and the conversion of hydroxyapatite to fluoridated apatite was estimated chemically and by X-ray diffraction. The differences of the mean fluoride uptakes from the very different concentrations of fluoride given were significant. Prolonged washing of the bones with demineralized water released 5-10 per cent from the fluoride uptake. Formation of fluoridated apatite was evident by decreases in the a parameter of the hydroxyapatite phase. In the washed bones, there was no appreciable transformations in the a parameters. The co-existence of Mg-containing beta-Ca3(PO4)2 with the apatite phase was detected in heated bone samples. The amount of beta-Ca3(PO4)2, its dependence on the age of the bones and its Mg content are interdependent.

Animals↗