摘要:

Fluoride uptake, topographic distribution, and effect on human dental enamel following topical treatment (for 4 min, 8 min and 72 h) with an acidulated fluoride-phosphate solution have been studied by means of electron probe X-ray microanalysis and X-ray diffraction. The samples examined were divided into a non-washed group, and a washed group from which excessive and loosely bound F had been eliminated from the enamel. The topographic distribution of fluorine was demonstrated by electron probe X-ray microanalysis. In the non-washed samples, an outer layer with a higher concentration of F, and adjacent to this another layer having a moderate concentration of F, were observed. After a prolonged washing about 90% of F of the outer layer was eliminated, whereas that of the inner layer persisted. X-ray diffraction analysis shows the presence of CaF2 in non-washed samples; the lines of CaF2 disappear after prolonged washing. On the other hand, a displacement of the apatite lines was observed in all treated samples, corresponding to a shortening of the parameter a of the unit cell, due to the replacement of the OH–– by F–– in the crystalline network. These results show that by topical treatment of enamel with an acidulated fluoride-phosphate solution, an accumulation of F in the surface layers of the enamel is produced, partly as CaF2 and partly as fluor

ISSN:0008-6568    

DOI:10.1159/000259621

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Enzyme preparations obtained from bacterial plaque, whole saliva and carious dentine were studied with respect to their ability to hydrolyze various phosphates. The substrates used were selected to represent the following biologically important phosphates: hydroxyalkyl phosphates, alkyl phosphates, enol phosphates, phosphoramidates, dialkyl phosphates, alkyl pyrophosphates, P1P2-dialkyl pyrophosphates, and alkyl triphosphates. The enzyme preparations exhibited a versatile reactivity pattern because all types of phosphates were hydrolyzed at a fairly high rate. Product inhibition (by phosphate, tested at 0.05 × 10––3 –– 1.0 × 10––3 M) was seen to be a feature of the enzymic hydrolysis of p-nitrophenyl phosphate. 1 mM MgCl2 slightly activated most of the catalyses studied. Certain quaternary ammonium compounds were seen to activate the hydrolysis of p-nitrophenyl phosphate (e. g. tetramethylammonium iodide by approximately 5 % and those with longer alkyl chains, e. g. benzethonium chloride, domiphen bromide, dequalinium chloride and cetylpyridinium chloride, by appro

ISSN:0008-6568    

DOI:10.1159/000259622

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Polished fluorapatite crystal surfaces were etched with lactic acid adjusted to pH4 or with ethylenediamine tetra-acetic acid (Edta) and the surfaces examined by scanning electron microscopy. The resultant acid etch patterns or pits were observed to be typical of the hexagonal system, as expected from the crystal structure of fluorapatite; however, the fluorapatite surfaces exposed to Edta at pH7 were relatively unaffected. Several different natural surfaces of fluorapatite were exposed to lactic acid and the comparative dissolution rate for each surface determined by the micro estimate of the dissolved calcium component. Observations indicated similar dissolution rates for the different surfaces examined. A relatively simple technique was employed to compare dissolution rates of human enamel and fluorapatite under static conditions. Sample granules were suspended upon porous glass filter crucibles and weight losses of the granules versus the time of dissolution were recorded for a variety of solutions. Constant rates of dissolution were obtained, fluorapatite exhibiting low values in lactic acid and EDTA solutions compared with high dissolution rates observed for enamel granules in these solutions. The rate of rate loss of enamel granules in 0.15 M Edta is higher than that in 0.25 M lactic acid. Surprisingly, the opposite was observed for fluorapatite granules.

ISSN:0008-6568    

DOI:10.1159/000259623

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Thirty-five erupted and 15 unerupted caries-free teeth were painted with varnish leaving ‘windows’ of enamel on buccal and lingual surfaces. Each tooth was slit in half longitudinally and one half, selected at random, was stored in a calcifying fluid whilst the control half was placed in distilled water. The calcifying fluid was used in the range pH 6.8–7.4. Tooth halves were exposed to the fluids from 1–24 weeks, the solutions being renewed every other day. After exposure, the ‘windows’ were brushed with water using an automatic toothbrush. After this, the tooth halves were placed in acidified gelatin gels. Both halves of each tooth were exposed to identical conditions of attack and exposure time. After exposure to the gels from 8–24 weeks, longitudinal sections through the lesions were examined with the polarizing microscope. Results of qualitative and quantitative imbibition studies indicate differences in histology, rate of attack and internal pore volume between control and experimental lesions. The controls were more severely affected than the precalcified experimental halves with respect to these criteria. The ‘beneficial’ effect of the calcifying fluid was more marked with unerupted than with erupte

ISSN:0008-6568    

DOI:10.1159/000259624

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Using an optical comparator and standardized sections, morphological and caries comparisons were made of the molars of rats which had been subjected to sugar injections during tooth formation. This treatment did not modify tooth morphology. Narrower deeper fissures tended to decay more frequently, the extent of caries was greater in such fissures, and not directly related to enamel thickness. Morphological differences between litters were significant.

ISSN:0008-6568    

DOI:10.1159/000259625

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Three intraperitoneal injections daily of 1 mg/gm body weight of 20% lactose, glucose-fructose and sucrose in saline, in rats from the 10th to 19th day did not give a definite effect on caries prevalence or extent after 35 post-weaning days on a nutritionally adequate cariogenic ration. There were no effects on weight gain before or after weaning, food consumption or femoral and mandibular weights.

ISSN:0008-6568    

DOI:10.1159/000259626

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

In order to measure caries inhibition by means of the local application of fluoride gel and a new fluoride-containing varnish, three groups of Osborne-Mendel rats, each consisting of 20 animals, were tested in a short-term experiment. Amine fluoride containing gel and fluoride varnish were applied with a soft paint brush to the molars of each half-mandible. The diet Stephan 580 and distilled water were given ad libitum 2 h after the application of the fluoride preparation. By comparing the severity of the lesions produced, both fluoride-containing agents were shown to exhibit caries-inhibiting activity. The gel which contained the amine fluoride, and the fluoride-containing varnish, showed a fairly similar degree of inhibition when compared to the control group.

ISSN:0008-6568    

DOI:10.1159/000259627

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

A clinical investigation on caries attack of different dental surfaces was carried out in a high fluoride area (Campagnano) in 144 adults. At the same time the fluoride concentration of 269 samples of different dental surfaces of 65 caries-free teeth, belonging to adults from the same area, was determined. Statistical analysis of clinical and chemical data, and a comparison between these data and earlier data collected in a low fluoride area (Rieti) were carried out. Highly significant differences, both in caries susceptibility and in fluoride content, were found in Campagnano between the occlusal and the other four surfaces (the occlusal surfaces were the most affected by caries and the lowest in fluoride). In Rieti similar findings were observed in the clinical data but not in chemical data. All surfaces in Campagnano showed a significantly higher fluoride content than the surfaces in Rieti and a significantly lower percentage in caries. However, the increase in fluoride content varied for the different surfaces. Caries reduction was also not the same for different surfaces.

ISSN:0008-6568    

DOI:10.1159/000259628

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Using the ‘decile character number method’, the view held generally that controlled diabetes leads to an earlier loss of the teeth was not confirmed. The study involved 308 diabetics, the majority of whom were in the older age groups. Additionally, some advantages and shortcomings of this new epidemiological method were discus

ISSN:0008-6568    

DOI:10.1159/000259629

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The position of fluoride ions occurring as minority in hydroxyapatite has been determined by means of nuclear magnetic resonance. The fluoride ions form magnetic resonance part of the linear chains of hydroxyl ions in one of the configurations OH-F-vacancy or OH-F-HO. A fluoride ion in this position will block diffusion along these chains. This may help to understand how very small amounts of fluoride are able to reduce the development of caries.

ISSN:0008-6568    

DOI:10.1159/000259630

出版商:S. Karger AG    

年代:1970

数据来源: Karger