摘要:

Plaque was removed from the teeth of 2 monkeys which had been fed on a standard cariogenic diet. They were then fed entirely by stomach tube for a 7-day period. Tube feeding was continued for a further such period during which 1 animal was given glucose and the other sucrose by mouth. In a final 7-day period the 2 sugars were interchanged between the monkeys while all the other dietary constituents continued to be given by tube. Plaque samples were taken at the end of each period, hydrolysed and subjected to quantitative amino acid analysis. The percentage of total protein in the plaque was maintained during tube feeding and enhanced when additional sugar was given by mouth. The protein of the various plaque samples was fairly constant in composition and conformed to a definite pattern with fairly high proportions of glutamic acid and alanine and moderate amounts of many amino acids. This composition closely resembled that of plaque from human teeth. It was concluded that salivary proteins rather than newly-ingested food are the main immediate source of the entire protein content of dental plaque.

ISSN:0008-6568    

DOI:10.1159/000259738

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The aim of this study was to investigate the nature of a factor present in human whole saliva which causes the aggregation of certain oral bacteria. It seemed possible that the factor causing aggregation could play a part in plaque formation in that it could promote adhesion of organisms to the teeth and contribute to the mutual adhesion of the organisms in the plaque. Agarose column chromatography of human whole saliva gave a void volume peak which contained the aggregating activity. Investigation of this material showed it to contain 33% protein, 19% anthrone positive carbohydrate, 2.9% N-acetyl neuraminic acid and substantial amounts of hexosamine. Data from ultracentrifugal analysis, agarose column chromatography, amino acid analysis, isoelectric focusing and cetyl trimethylammonium bromide fractionation indicated that the active material was a high molecular weight glycoprotein which exists in solution in a random coil configuration. It was further found that the active material was selectively adsorbed on to the hydroxy-apatite surface and also that a component with properties similar to those described above could be isolated from dental plaque. It seems, therefore, that there is, in whole saliva, a high molecular weight glycoprotein, which selectively adsorbs on to the apatite surface and which causes aggregation of certain oral organisms. It seems possible that this component plays a significant role in the initial selective adhesion of certain oral organisms to the tooth surface, as well as being involved in the mutual adhesion of the organisms in the developing plaque.

ISSN:0008-6568    

DOI:10.1159/000259739

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

Further investigation of the extracellular glucosyltransferase activity of Streptococcus sanguis, strain 804 has revealed several glucosyltransferase enzymes with isoelectric points at pH 7.9, 6.4 and less often at about 4.5. The principal enzyme fraction, Ip 7.9, has been shown to be a pure homogeneous protein moving as a single active band by polyacrylamide gel electrophoresis. The equilibrium of the reaction catalyzed by the glucosyltransferase Ip 7.9 is highly in favour of polysaccharide formation based upon the observed disappearance of sucrose and appearance of reducing sugar. No reversibility of the reaction to form sucrose from fructose and dextran could be demonstrated.

ISSN:0008-6568    

DOI:10.1159/000259740

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The object of this study was to evaluate the decalcifying ability of some complex forming agents present in the dental plaque, when applied topically to enamel and dentin surfaces under neutral pH conditions in vitro. Some preliminary experiments were carried out on freshly extracted young permanent teeth with neutralized plaque material undergoing glycolysis. The decalcifying effect of sodium salts of amino acids and lactic acid was also studied in the region of neutral pH. Eighty-eight freshly extracted human permanent teeth were prepared using a specially designed window technique. One half of the experimental areas was exposed to the respective agents, while the other half served as a control. The decalcifying effect was estimated by means of the 32P uptake. The results showed that the agents tested were able to decalcify enamel and dentin surfaces at neutral pH. On the basis of these findings, a modified caries hypothesis is proposed which suggests that decalcification is mainly initiated upon the intake of carbohydrates and is a combined effect of acid dissolution during the low pH phase and complex forming agents while the plaque is neutral, a number of complex forming substances being formed by the breakdown of proteins.

ISSN:0008-6568    

DOI:10.1159/000259741

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

A description is presented of a method for tube-feeding solutions to newborn rats on a daily basis. The technique is quick, accurate, simple, reasonably safe and without apparent effect on the health, growth rate or caries-susceptibility of the rats. Newborn rats were randomly allocated to groups receiving twice daily doses of 10-per cent solutions of sucrose or lactose or distilled water by stomachtube up to 17 days of age. Subsequently, all the rats were fed the same caries-producing diets until they were killed at 81 days of age. No significant differences between the caries susceptibilities of the groups could be discovered.

ISSN:0008-6568    

DOI:10.1159/000259742

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The distribution of caries by tooth, by location on the tooth and by age in 504 Anglo-Saxon dentitions was determined as a baseline for quantitative comparisons with similar investigations currently being made in dentitions from the Iron-Age, Romano-British and Mediaeval periods and the 18th to 20th centuries. Excluding gross cavities, caries was commonest overall at the cemento-enamel junction, particularly on the interstitial surfaces, the majority of these cavities beginning in cementum. Caries at contact areas or in buccal fissures was rare as was caries at any site in the deciduous dentition. In the youngest two age-groups, caries occurred most frequently in the occlusal fissures but subsequently declined possibly because attrition progressed more rapidly than the caries process. Molars were attacked more frequently than incisors, canines or premolars. The number of cavities near the cemento-enamel junction increased with attrition and with alveolar recession. This finding is in agreement with the suggestion that caries began at this site as destruction of the crown-form by attrition allowed food to pack at the gingival margin and as the resultant alveolar recession led to exposure of the cementum. The lack of sugar in the Anglo-Saxon diet was probably an important factor in the rarity of cavities at the contact areas or in the fissures.

ISSN:0008-6568    

DOI:10.1159/000259743

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

One sample of soft deposit was taken from each of 143 11 to 13-year-old children performing weekly mouth rinses with 10 ml 0.2% NaF or 0.2% NaCl. F was determined, and the ppm F calculated on the dry weight basis. The mean ppm F was 55 ± 53. F decreased with increased weight of samples. Neither F, tooth-brushing before rinsing, nor sex had any significant effect on F in plaque samples collected 4–5 days after the last rinsing. In a previous series comprising 57 children, the ppmF was elevated about 1 day after NaF rinses. The effect of F in plaque is discussed with respect to gingivitis and cari

ISSN:0008-6568    

DOI:10.1159/000259744

出版商:S. Karger AG    

年代:1971

数据来源: Karger

摘要:

The anticaries effects of topically-applied NaF and SnF2 solutions and of a SnF2 dentifrice were compared under a wide variety of experimental conditions in rats. The parameters examined included: concentration of fluoride, frequency of application of fluoride, age of animal, duration of study and extent of lesion formation. The anticaries efficacy of fluoride (SnF2 or NaF) was significantly increased as the concentration of fluoride and the frequency of application were increased. No consistent superiority was found for one compound (SnF2 versus NaF) over the experimental conditions studied. The age of the animal, duration of study and extent of lesion formation did not significantly alter the relative efficacies of SnF2 and NaF.

ISSN:0008-6568    

DOI:10.1159/000259745

出版商:S. Karger AG    

年代:1971

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000259746

出版商:S. Karger AG    

年代:1971

数据来源: Karger