摘要:

Glucosylsucrose and maltosylsucrose are principal constituents of coupling sugar, which is prepared from starch and sucrose and has a similar taste to cane sugar. Cell suspensions of Streptococcus mutans grown in a continuous culture under sucrose limitation produced only a small amount of acids from these sugars. The rate of hydrolysis of these sugars by cell-free extract of S. mutans was less than 10% of that of sucrose. Addition of sucrose or glucose lowered the pH in deposits of S. mutans but addition of glucosylsucrose or maltosylsucrose did not. We conclude from these findings that S. mutans ferments these sugars to a limited extent.

ISSN:0008-6568    

DOI:10.1159/000260460

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Intact cells of Streptococcus mutans K-1 were incubated with enamel powder in buffer, pH 5.8, saturated with enamel salts, the cells or the enamel having been previously labelled with 32P. The cells were also incubated with p-nitrophenyl phosphate at varying pH or at pH 4.8 with varying concentrations of fluoride. Incubation of the K-1 cells with 32P-labelled enamel caused an equilibration of enamel 32P within the cells. During sucrose fermentation, the uptake of enamel 32P by the K-1 cells was rapidly increased several times higher than that of the controls. In the presence of fluoride, there was an increased liberation of bacterial 32P and the uptake of this by enamel was doubled. There were changes in the bacterial total phosphate corresponding to the fermentative accumulation of 32P of enamel origin within the cells or to the fluoride-induced release of 32P out of them. The acid phosphatase of intact K-1 cells had a maximum activity at pH 4.8 and a lower peak at pH 5.8. At pH 4.8, a fluoride concentration of 20 ppm inhibited this activity almost to zero. The results emphasize the phosphate translocation between enamel and bacteria as a common denominator in the enamel destruction and repair, In the former case this and the acid phosphatase may support the acid attack. The results with fluoride may partly explain its caries-inhibitory functions.

ISSN:0008-6568    

DOI:10.1159/000260461

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Human saliva was chromatographed on Sepharose CL-2B and was found to separate into two peaks. The first peak contained nonspecific agglutinin(s) as the agglutinin gave similar titers with all Streptococcus mutans serotypes. No protein or α- and γ-chain or secretory piece activity was found in association with this agglutinin. Components of the second peak demonstrated protein, α- and γ-chain and secretory piece activity as evidenced by precipitation lines in gel diffusion using the appropriate monospecific antisera. The agglutinin contained in this peak when derived from different individuals showed varying titers against different serotypes of S. mutans. The second peak was also chromatographed on Sephadex G-200. A specific agglutinin was then found in the void volume peak which demonstrated α-chain and secretory piece activity as shown by gel diffusion studies. The results from this work would appear to demonstrate a nonspecific agglutinin and a specific agglutinin which has all the properties of S

ISSN:0008-6568    

DOI:10.1159/000260462

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

A direct correlation between extractable ATP content of plaque and plaque wet weight has been found. Moreover, the ATP measurement allows for an estimation of the number of viable cells in plaque. The method used is quick and simple. The sensitivity is very high; microgram amounts of plaque are analyzable.

ISSN:0008-6568    

DOI:10.1159/000260463

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The formation of the bacterial inhibitor, hypothiocyanite (OSCN––) ion, by human salivary sediment was studied in relation to oral health. Persons with good oral health produced significantly more OSCN–– ions than those with poor oral status. However, no relation in the amount of SCN–– ions and the activity of free or cell-bound peroxidase to oral health was found. This suggests that the difference in OSCN–– formation results from differences in endogenous H2O2 production. It is not sure that increased OSCN–– production leads to better oral health, possibly vice versa, but anyway there is a clear positive correlation. About 80% of oral total peroxidase activity was found to be bound

ISSN:0008-6568    

DOI:10.1159/000260464

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Incipient carious lesions were examined by the SEM technique with the purpose of demonstrating the invasion of microorganisms under lesions without cavitation on the enamel surface. Microorganisms were seen to penetrate fairly deeply into the lesions. In some cases, they reached the dentino-enamel (DE) junction before any cavitation of the surface had ocurred. A gap between the enamel and the dentin could be completely filled with microorganisms. In some advanced attacks there was not only lateral spread of infection along the DE junction, but also outward (retrograde caries) as well as pulpward destruction, even before cavitation on the surface. Microorganisms seemed to be capable of removing enamel structures by direct action in a way similar to that of osteoclasts dissolving bone.

ISSN:0008-6568    

DOI:10.1159/000260465

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Selective culture media were used for the isolation of microorganisms from the lingual developmental groove and the buccal surface of the upper right second deciduous molar tooth in 22 monkeys. Samples of pooled plaque were also cultured for streptococci. Some of the lingual grooves became carious during the study. Fusobacteria formed a greater percentage of the cultivable flora on the buccal surface but streptococci, and in particular strains of Streptococcus mutans serotype c, were more numerous in the lingual groove.

ISSN:0008-6568    

DOI:10.1159/000260466

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The action of the fluoride ion has been investigated using calcium-deficient hydroxyapatites with compositions comparable with dental mineral. Whereas during carious dissolution there is a preferential loss of calcium by the mineral, the action of fluoride is to cause a preferential acquisition of calcium by the calcium-deficient mineral. The calcium: phosphorus ratio of material acquired by suspended hydroxyapatite on addition of fluoride was always in excess of the theoretical 1.67 for hydroxy- or fluorapatite and this is consistent with a selective uptake of calcium by the depleted mineral.

ISSN:0008-6568    

DOI:10.1159/000260467

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

In a long-term study of over 20,000 children aged 6–15 (permanent dentition) and over 12,000 children aged 3–8 years (deciduous dentition), the caries prevalence (DMFT and dft indices) was shown to depend directly upon maintaining water fluoridation at a constant level of 1.0 ± 0.1 ppm F. For a period of 12 years, following the introduction of water fluoridation in Karl-Marx-Stadt in 1959, there was a reduction in caries incidence followed by a slight increase when, for technical reasons, the fluoride concentration was suboptimal for several years. Once fluoridation to 1.0 ppm was reinstated, this slight increase in caries incidence disappeared. Only after 18 years of water fluoridation, however, was the situation thoroughly restored and the observations made in the present paper stress the need for precise technological control and for a constant monitoring of fluoride concentrations in the drinking w

ISSN:0008-6568    

DOI:10.1159/000260468

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

One of the mechanisms proposed for the caries-reducing effect of fluoride is diffusion inhibition of OH–– groups through the 63 columns of the apatite structure thereby increasing the resistance of the crystal against acidic attack. The validity of this hypothesis was checked by investigation of the reactivity of solid solutions of hydroxyapatite and oxyapatite for oxydation during storage for 3 years in air. These solid solutions provide the same number of vacancies in the OH positions as occur in the apatite of tooth enamel, whereas the mobility of the OH–– ions is the critical quantity for its reactivity in analogy with fluorhydroxyapatite solid solutions. It was found that the solid solutions were not oxydized as their lattice parameters did not change during the storage period although the experimental period was far within the limits of the theoretical estimate. This invalidates the proposed mechanism for the caries-reducing effect of fluoride, as it proves the solid state diffusion is not important in apatites at normal tempe

ISSN:0008-6568    

DOI:10.1159/000260469

出版商:S. Karger AG    

年代:1980

数据来源: Karger