RESUMEN
1. The morphological aspects of globules deposited in vitro when a NaF solution is applied to sound human enamel were studied by scanning electron microscopy. 2. Particles, presumably of calcium fluoride-like material, formed on the surfaces of an unerupted tooth and consisted of subunits showing a "cauliflower" appearance, indicating agglomeration of even smaller particles. The number and size of the crystals increased with time of exposure. 3. These particles represent highly resistant fluoride reservoirs and may be of clinical significance.
Asunto(s)
Fluoruro de Calcio/farmacología , Depósitos Dentarios/ultraestructura , Esmalte Dental/ultraestructura , Fluoruro de Sodio/farmacología , Humanos , Microscopía Electrónica de RastreoRESUMEN
1. The morphological aspects of globules deposited in vitro when a NaF solution is applied to sound human enamel were studied by scanning electron microscopy. 2. Particles, presumably of calcium fluoride-like material, formed on the surfaces of an unerupted tooth and consisted of subunits showing a "cauliflower" appearance, idnciating agglomeration of even smaller particles. The number and size of the crystals increased with time of exposure. 3. These particles represent highly resistant fluoride reservoirs and may be of clincial significance
Asunto(s)
Humanos , Esmalte Dental/ultraestructura , Depósitos Dentarios/ultraestructura , Fluoruro de Calcio/administración & dosificación , Técnicas In Vitro , Fluoruro de Sodio/administración & dosificación , Microscopía Electrónica de RastreoRESUMEN
Enamel specimens from unerupted third molars were treated with the supernatant of monofluorophosphate (MFP)-containing toothpaste slurries in water. Calcium fluoride-like particles were formed on the enamel surface during a 24-h exposure. The globules were soluble in alkali. More particles were seen on enamel treated with a toothpaste containing both MFP and NaF. The experiments showed that the calcium fluoride-like material formed on enamel after treatment with MFP-containing toothpaste probably originates from the free fluoride present in the pastes. The relatively moderate deposition of fluoride may be of clinical significance because the teeth are so frequently exposed to toothpaste. No firmly bound fluoride was found on treatment of enamel with MFP-containing toothpaste.
Asunto(s)
Fluoruro de Calcio/farmacocinética , Esmalte Dental/metabolismo , Fluoruros/administración & dosificación , Fluoruros/farmacocinética , Fosfatos/administración & dosificación , Pastas de Dientes , Adsorción , Fluoruro de Calcio/análisis , Fluoruro de Calcio/química , Esmalte Dental/química , Esmalte Dental/ultraestructura , Fluoruros/análisis , Fluoruros/química , Humanos , Hidróxidos , Microscopía Electrónica de Rastreo , Fosfatos/química , Compuestos de Potasio , Fluoruro de Sodio/administración & dosificación , SolubilidadRESUMEN
The uptake of alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) and alkali-insoluble fluoride (apatitically bound fluoride) on sound human enamel from treatment with Duraphat or a neutral 2% NaF solution was investigated in vitro. Blocks from impacted third molars were used. More fluoride was deposited on the enamel from the neutral 2% NaF solution than from the Duraphat treatment. All the fluoride could be dissolved in alkali. Globules of calcium fluoride-like material were demonstrated by scanning electron microscopy. Chemical analysis showed no measurable increase in the apatitically bound fluoride (alkali-insoluble fluoride) after brief exposures. Duraphat-treated samples submerged in water after the exposure lost only about 50% of the deposited fluoride, whereas samples treated with 2% NaF are known to lose all their fluoride under similar circumstances, a condition which may be related to the favorable clinical effect of Duraphat.
Asunto(s)
Esmalte Dental/metabolismo , Fluoruros Tópicos/farmacocinética , Fluoruros/farmacocinética , Hidróxidos/química , Compuestos de Potasio , Potasio/química , Fluoruro de Sodio/farmacocinética , Grabado Ácido Dental , Adsorción , Apatitas/química , Fluoruro de Calcio/química , Esmalte Dental/ultraestructura , Fluoruros/química , Fluoruros Tópicos/administración & dosificación , Fluoruros Tópicos/química , Humanos , Microscopía Electrónica de Rastreo , Fluoruro de Sodio/administración & dosificación , Fluoruro de Sodio/química , SolubilidadRESUMEN
The first aim of the present study was to examine if alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) forms when a NaF-containing toothpaste is applied on human enamel surface in vitro. The centrifuged supernatants of toothpastes dissolved in distilled water were used and four different commercial NaF-containing toothpastes were tested. The second aim was to investigate if pyrophosphate would interfere with the deposition of alkali soluble fluoride. The formation of alkali-soluble fluoride was determined by chemical analysis and visualized by scanning electron microscopy (SEM). It was ascertained that all tested toothpastes contained free fluoride according to the manufacturers' specifications. It was shown that they promoted deposition of alkali soluble fluoride on the enamel surface. The amount of deposited material increased with the time of exposure. The clinical effect of a NaF-containing toothpaste may thus well depend on an initial formation of alkali-soluble fluoride. Fluoride from this reservoir may adsorb onto the enamel crystals and inhibit further demineralization or increase the rate of remineralization during cariogenic challenges. It was also demonstrated that pyrophosphate did not interfere with the deposition of alkali soluble fluoride.
Asunto(s)
Fluoruro de Calcio/química , Esmalte Dental/ultraestructura , Difosfatos/química , Fluoruros/química , Fluoruro de Sodio/química , Pastas de Dientes , Adsorción , Álcalis , Fluoruro de Calcio/análisis , Esmalte Dental/química , Electroquímica , Fluoruros/análisis , Humanos , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , SolubilidadRESUMEN
Fluoride uptake on and in enamel during topical application of acidulated solutions was studied. The variables were different time intervals and different pH levels of the treatment solutions. The experiment was carried out with human enamel exposed to 2% NaF solutions, pH 3.5 and 5.5, for 30 sec, 60 sec, 5 min, and 60 min. The amounts of fluoride formed on (as calcium fluoride) and in (as fluorapatite) enamel were determined by chemical assessments, and scanning electron microscopy provided the visualization of the deposits on the surface. It could be demonstrated that the two pH levels caused deposition of large amounts of calcium fluoride and that almost twice as much was deposited at pH 3.5 as at 5.5. The amount of deposit increased rapidly with time of exposure in both situations compared with similar experiments with neutral fluoride solutions. Firmly bound fluoride was incorporated in the enamel only during the 60-min incubation.
Asunto(s)
Esmalte Dental/metabolismo , Fluoruros Tópicos/farmacocinética , Fluoruro de Sodio/farmacocinética , Fluoruro de Calcio/metabolismo , Cristalización , Esmalte Dental/ultraestructura , Humanos , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Factores de TiempoRESUMEN
The aim of this study was to quantify the formation of alkali-soluble fluoride (loosely bound fluoride such as calcium fluoride-like material and absorbed fluoride) and alkali-insoluble fluoride (firmly bound fluoride or apatitically bound fluoride) when fluoride mouthrinsing solutions were applied on sound human enamel in vitro. Two commercial products containing 0.2% or 0.05% NaF were used during 30 sec, 60 sec, 5 min, and 60 min. The formation of loosely bound fluoride was determined by KOH extraction and visualized by scanning electron microscopy. The firmly bound fluoride was measured by three consecutive acid etchings of the enamel. Even during short periods of application there were deposits on the enamel surface. The amount of deposit increased with time of exposure to the 0.2% NaF solution. Only after treatment for 60 min with 0.05% NaF were significant amounts of alkali-soluble fluoride deposited. No measurable amounts of firmly bound fluoride were observed.
Asunto(s)
Esmalte Dental/química , Antisépticos Bucales/química , Fluoruro de Sodio/química , Fluoruro de Calcio/análisis , Esmalte Dental/ultraestructura , Humanos , Microscopía Electrónica de Rastreo , Diente Molar , Propiedades de Superficie , Factores de TiempoRESUMEN
Deposition of alkali-soluble fluoride on enamel in the presence and absence of an acquired pellicle was studied in vitro during a single topical application of a 2% sodium fluoride solution at neutral pH. Five experimental groups of repeated measures design were established. The amount of alkali-soluble fluoride formed on enamel (i.e., calcium fluoride) was measured by chemical assessments and by SEM. The results showed that there were no differences among the groups demonstrating the incapacity of pellicle to interfere with deposition of alkali-soluble fluoride on enamel. The fluoride ions are thus able to reach the enamel in spite of the presence of the pellicle.
Asunto(s)
Fluoruro de Calcio/metabolismo , Depósitos Dentarios/metabolismo , Esmalte Dental/metabolismo , Fluoruros Tópicos/farmacocinética , Fluoruro de Sodio/farmacocinética , Álcalis , Esmalte Dental/ultraestructura , Película Dental , Humanos , Microscopía Electrónica de Rastreo , Saliva/metabolismo , Simeticona/química , SolubilidadRESUMEN
PIP: A method for the radiological examination of the uterus, used to study the behavior of the uterus in the presence of a foreign body, such as an IUD, is described. A total of 44 patients were studied, of which 26 wore IUDs. A much higher incidence of varicocele was found among patients with IUDs (13 out of 26 cases, as compared with 5 out of 13 cases in the control group). The report is followed by a discussion, of the question of whether the higher incidence of varicocele may be related to the use of IUDs. It is suggested that a new study should be conducted, using the same patients as controls and examining them for a long period of time to detect the development of changes in their pelvic vascular system.^ieng