摘要:

In 47 patients plaque samples were taken from sound and carious root surfaces. The carious surfaces were categorized as soft or hard. In total, 70 sound, 29 hard carious and 36 soft carious surfaces were sampled and analyzed for the presence of Streptococcus sanguis, Streptococcus mutans, Actinomyces viscosus/naeslundii, Lactobacillus and Capnocytophaga species. Samples from soft carious surfaces contained significantly higher numbers of S. mutans as compared to samples from sound surfaces. The numbers of S. mutans on hard carious and sound surfaces were approximately equal. For S. sanguis and A. viscosus/naeslundii no significant differences were found. The isolation frequency of Capnocytophaga was comparatively low. Lactobacilli were only occasionally found. The results indicate that, from the above species, only S. mutans is closely related with root surface caries.

ISSN:0008-6568    

DOI:10.1159/000261021

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

A very sensitive method for protein determination by means of o-phthalaldehyde was developed. Plaque wet weight is not suitable for standardizing small plaque samples, but protein content of plaque can be used to measure plaque quantity precisely.

ISSN:0008-6568    

DOI:10.1159/000261022

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Saccharin markedly decreased the sorbitol- and mannitol-dependent growth rate and growth yield of Streptococcus mutans NCTC 10449 and also decreased the amount of acid produced from these hexitols by the organism. In addition, saccharin increased both the lag phase when glucose-grown cells were placed in a medium which contained sorbitol or mannitol as the primary energy source and to also increase the diauxie portion of the growth-response curve when glucose-grown cells were placed in a medium which contained a mixture of glucose and sorbitol or mannitol as fermentable energy sources. One mechanism by which saccharin may exert its negative effect upon hexitol catabolism by S. mutans is through inhibiting the activity of two inducible NAD-dependent oxidoreductases, sorbitol-6-phosphate dehydrogenase and mannitol-1-phosphate dehydrogenase which are found at high specific activities in extracts obtained from sorbitol- or mannitol-adapted cells respectively. Saccharin exerted a negative effect upon the enzymes by competitively inhibiting their interaction with both their oxidized and reduced coenzymes, NAD and NADH. In contrast, the inhibitor had no effect on the interaction of the enzymes with their respective substrates, mannitol-1-phosphate and sorbitol-6-phosphate.

ISSN:0008-6568    

DOI:10.1159/000261023

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

L-Sorbose, a ketohexose isomeric with fructose, is one of a group of hypoacidogenic sugars with potential utility as a sucrose alternative in confectionery. In the present study, Streptococcus mutans and Streptococcus milleri were grown in pure continuous culture under glucose-limited conditions in a chemically defined medium at a dilution rate of D = 0.1 h––1. Such conditions were aimed at simulating those thought to occur in dental plaque. Cultures were exposed to transient excesses of sorbose and/or glucose such as might occur at or inbetween meals. The presence of sorbose did not affect the normal response of S. mutans to excess glucose but, in higher concentrations, it reduced both acid production and growth – possibly via a futile cycle – and the organism began to wash out. Sorbose had no effect on S. milleri, which might give this organism an ecological advantage in plaque exposed to sorbose. Further studies on this potential sugar substitute seem wa

ISSN:0008-6568    

DOI:10.1159/000261024

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Artificial laminated carious lesions were made on the buccal surface of human premolars. The volume percentage of mineral was determined as a function of depth by microradiography. Using the electron microprobe, the signals for Ca, Na, Mg, P and Cl were recorded as a function of depth both through the lesions and through the adjacent sound enamel. In the demineralized parts of the lesions there was a preferential loss of Na and a preferential retention of Cl. In the surface layers and the laminations the Na/Ca and Cl/Ca ratios were practically the same as in the adjacent sound enamel. This indicates that these surface layers and laminations were not formed by gross dissolution of the original mineral followed by gross precipitation of another, less soluble calcium phosphate, but that they remained there during the continuous demineralization due to the fact that the microcrystals became resistant to dissolution, perhaps due to protection by a thin layer of precipitated fluorapatite or fluoridated hydroxyapatite. In a previous study the same was found for surface layers and laminations in natural laminated carious lesions. This indicates that during continuous in vitro demineralization tooth enamel mineral behaves similarly as during intermittent in vivo demineralization.

ISSN:0008-6568    

DOI:10.1159/000261025

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Synthetic polymer gels have been examined as decalcifying media for the preparation of artificial carious lesions in tooth enamel. Enamel specimens were demineralized in lactic acid/calcium phosphate buffers containing 0.1–0.5% (w/w) polyacrylic acid (Carbopol C907, MW = 450,000 daltons) to act as a surface-protective agent. The rate, histology and physical characteristics of lesions were characterized by surface microhardness, polarized light, and microradiographic analyses. Following demineralization, selected lesions were remineralized in solutions supersaturated with respect to fluoroapatite. The results show that polyacrylic acid is extremely useful and effective as a surface-protective agent for artificial carious lesion preparation. The histology of lesions formed in C907 gels can be carefully controlled by adjusting the undersaturation of the demineralization medium with respect to tooth mineral salts. Lesions formed in C907 gels are extremely reactive towards remineralization and the rate and histology of mineral repair are not noticeably influenced by the resin content in solution. The use of synthetic polymer gels is recommended for the systematic reproducible preparation of artificial carious lesions in dental ename

ISSN:0008-6568    

DOI:10.1159/000261026

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Electrophoretic separated matrix proteins from partly mineralized bovine enamel were stained by Coomassie blue and silver techniques. Conventional Coomassie staining was sufficient for demonstration of high molecular weight proteins on SDS PAGE. A Coomassie blue G-formaldehyde mixture was suitable for detection of the low-molecular-weight proteins. This staining mixture is also suitable for visualization of enamel proteins in isoelectric-focused gels. The high resolution of two dimensional electrophoresis is proved on the 67,000-dalton enamel protein fraction. Silver staining is superior to Coomassie blue for detection of small amounts of enamel proteins. A combination of Coomassie blue and silver staining result in very sharp bands on SDS PAGE.

ISSN:0008-6568    

DOI:10.1159/000261027

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000261028

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The state of the art of the research on a vaccine against dental caries has been reviewed. The subject has been analysed both from the biological and from the public health point of view. It is concluded that Streptococcus mutans plays a key role for the development of dental caries and that a vaccine directed against this microorganism could be a valuable adjunct to existing preventive measures in some countries. In others it could be a major public health measure. The unique characteristics of dental caries partly explain why a vaccine is not yet available. Protection against dental caries by immunization could be achieved by protective antibodies from serum, by IgA antibodies in saliva or by a combined effect of serum and salivary components. In rodents both peroral and parenteral immunization has provided protection against S. mutans infection and dental caries. In primates only parenteral immunization has given positive results. In humans peroral immunization has led to an increased salivary antibody activity in some studies but not in others. There is no conclusive evidence which shows that antibodies against S. mutans can influence dental caries activity in man. As structures on the cell surface of S. mutans cross-react with human tissue much work has been concentrated on identification of candidate antigens. Some of these have been purified and tested in vitro and in animal systems. Some protein antigens have given a clear-cut caries protection in primates and one of these has been produced in large amounts and is ready for testing in humans. Another candidate antigen, the enzyme complex called glucosyltransferase has shown protection in rodents and the effect of peroral administration of this antigen is now being tested in man. A considerable amount of knowledge has been obtained and the activity in the research area is high. Some groups have focused on basic immunology and have little understanding of the disease. In other groups the reverse is true. A consequence of this is that collaborative studies ought to be organized. By such studies key information about the possible role of antibodies in the development of dental caries in man could be obtained within a reasonable period of time.

ISSN:0008-6568    

DOI:10.1159/000261029

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The Isle of Lewis is an island community which has little movement of its school population and, since the Second World War, mirrors closely the rest of the United Kingdom in availability of foods, introduction of television and educational opportunities. One of the first major dental epidemiological studies was conducted on the island by King in 1937. Between 1968 and 1984 a further series of investigations has been conducted on this population by the present authors; these allow a comparison of caries prevalence at intervals of time over 47 years. The findings show a marked increase in dental caries from 1937 to 1971, an equally marked decrease during the remainder of the 1970s and a further modest increase among the younger age groups studied between 1981 and 1984.

ISSN:0008-6568    

DOI:10.1159/000261030

出版商:S. Karger AG    

年代:1987

数据来源: Karger