phosphorus-radioisotopes and Dental-Caries

This study aimed to establish a method for measuring the cariogenic potential of foods with high reproducibility in vitro.. Streptococcus mutans (S. mutans) was incubated in test foods with radioisotope polyacrylamide hydroxyapatite (PAHA) for 150 min at 37 °C. Then, the amount of radioisotope (32)P released from PAHA was measured using a liquid scintillation counter and scanning electron microscopy (SEM).. The radioisotope PAHA discs that were soaked in 10% sucrose solutions had a high cariogenic potential and showed a remarkably demineralized surface (p < 0.05). The radioisotope PAHA disc that was incubated with snacks that had a high cariogenic potential showed a remarkably demineralized surface via SEM. Candy had a relatively high cariogenic potential, whereas xylitol gum had a relatively low potential.. The cariogenicity of snacks can easily be evaluated by measuring the amount of (32)P released from radioisotope PAHA discs.

Topics: Acrylic Resins; Analysis of Variance; Cariogenic Agents; Dental Caries; Diet; Durapatite; Korea; Microscopy, Electron, Scanning; Phosphorus Radioisotopes; Reproducibility of Results; Streptococcus mutans; Sucrose; Xylitol

Members of the TGF-beta family of growth factors are important in modulation of odontoblast secretory activity during dental tissue repair. Odontoblast expression of TGF-beta isoforms during development leads to their sequestration within the dentin matrix, from where they may be released during carious injury and participate in reparative processes. Two receptors, implicated in TGF-beta-mediated cell signaling, have been identified immunohistochemically in both odontoblasts and pulpal cells of healthy and carious human molar teeth. This study aimed to characterize the expression of the TGF-beta receptors I and II in sound and carious teeth by means of in situ hybridization, to help our understanding of the response of these cells to TGF-beta stimulation. Sound and carious human third molar teeth were routinely processed immediately following extraction, and 10-microns paraffin-embedded sections prepared. These sections were hybridized with 32P-labeled probes to TGF-beta receptors I and II, and the subsequent signal was detected by autoradiography. mRNA for both receptors I and II was mainly detected within the odontoblasts and nerve-associated cells of healthy tissues, with expression at lower levels seen within the subodontoblast and pulp core cells. The expression in odontoblasts was higher for TGF-beta receptor I than for receptor II. Expression of both receptors was more homogenous in all pulp cells within carious teeth, because of an increase of signal within the underlying pulp cell population, including blood-vessel-associated cells. We conclude that the TGF-beta receptors I and II were expressed in odontoblasts and pulp cells, and that subtle variations in the levels of their expression could be involved in the tissue response to injury.

Topics: Activin Receptors, Type I; Autoradiography; Dental Caries; Dental Pulp; Dentin; Gene Expression; Humans; In Situ Hybridization; Molar, Third; Odontoblasts; Phosphorus Radioisotopes; Protein Isoforms; Protein Serine-Threonine Kinases; Radiopharmaceuticals; Receptor, Transforming Growth Factor-beta Type I; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; RNA, Messenger; Signal Transduction; Transforming Growth Factor beta; Wound Healing

Blocks of human enamel were cycled through a demineralization--F-treatment-remineralization procedure and then analyzed for fluoride and the presence of caries-like lesions. Treatments with a sodium fluoride gel (5000 ppm F) increased the enamel fluoride concentration to 6500 ppm F, whereas a stannous fluoride gel (1000 ppm F) increased enamel fluoride to about 1200 ppm F. Although a control treatment (water) allowed caries-like lesions to form, as observed by microradiography, no lesions were found in either of the fluoride-treated groups. When the experiment was repeated with radioactive teeth, mineral loss, as determined by release of 32P, was again greatest in the water-treated control group, but some loss was observed in the fluoride treatment groups. The least loss was found in the sodium fluoride group. It was concluded that the fluoride treatments not only increased enamel resistance but also enhanced remineralization so that calcium phosphate was replaced during the subsequent remineralization phase. Because of the probability that stannous ions were deposited during the stannous fluoride treatments, some of the apparent calcium phosphate re-deposition in this group was probably stannous compounds.

Topics: Absorptiometry, Photon; Dental Caries; Dental Enamel; Fluorides; Gels; Humans; Microradiography; Phosphorus; Phosphorus Radioisotopes; Placebos; Sodium Fluoride; Tin Fluorides; Tooth Remineralization

Initial lesions in bovine enamel were remineralized in vitro for periods lasting from one hour to two weeks; in some cases, remineralization was interrupted daily for a ten-minute APF application. After two weeks, surface coatings appeared on APF-treated specimens; SEM and TEM observations, including selected area and micro-electron diffraction, indicated both a layered structure within these coatings, and the predominance of calcium fluoride single crystals, ranging from 0.1 to 1.0 micrometer in size. Using double (45 Ca and 32 P) labeled remineralizing solutions, we obtained depth profiles of deposited labeled calcium and phosphate; these indicated that repeated APF applications prevented inward penetration of calcium and phosphate and limited the deposition of these ions to an outer surface region corresponding to the surface coating. These phenomena are explained in terms of the composition and apparent reactivity of the coating.

Topics: Acidulated Phosphate Fluoride; Animals; Calcium Chloride; Calcium Radioisotopes; Cattle; Crystallography; Dental Caries; Dental Enamel; Microradiography; Microscopy, Electron, Scanning; Phosphates; Phosphorus Radioisotopes; Potassium; Potassium Compounds; Sodium Fluoride; Time Factors; Tooth Remineralization

Topics: Animals; Calcium Radioisotopes; Dental Caries; Femur; Fluorides, Topical; Gels; Incisor; Mandible; Minerals; Molar; Phosphorus Radioisotopes; Proteins; Rats

During experimental research work carried out on animals with a view to clearing up the caries-forming processes, metabolic disturbances could be detected in the hard tissues of teeth after administering a cariogenic diet. The aim of the present work was to investigate the effects of tooth-pastes with calcium, phosphate and fluoride content upon changes in metabolic processes, and thus to clarify the mechanism of the anti-cariogenic effect exerted by fluoride tooth-pastes.

Topics: Animals; Calcium; Calcium Radioisotopes; Carbon Radioisotopes; Dental Caries; Diet, Cariogenic; Fluorides, Topical; Male; Phosphates; Phosphorus Radioisotopes; Rats; Tooth; Toothpastes

Topics: Calcium; Calcium Radioisotopes; Dental Caries; Dental Enamel; Humans; Phosphorus; Phosphorus Radioisotopes; Tooth

Topics: Dental Caries; Dental Pulp Cavity; Fluids and Secretions; Humans; Phosphorus; Phosphorus Radioisotopes; Phosphorus, Dietary

Topics: Animals; Dental Caries; Phosphorus; Phosphorus Radioisotopes; Phosphorus, Dietary; Rats; Tooth