摘要:

A sedimentation method for studying adsorption of microorganisms onto hydroxyapatite is described and compared with batch adsorption experiments. Data, which demonstrate the feasibility and the high reproducibility of the method, are reported for oral microorganisms collected from one individual and for one laboratory strain, KPSK 2, of Streptococcus mutans. It is concluded that the sedimentation method in combination with results from the batch experiments will give significant information on mechanisms involved in bacterial colonization of the tooth surface.

ISSN:0008-6568    

DOI:10.1159/000260165

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The oral establishment of various species of streptococci and lactobacilli has been studied on 25 infants during a period of 5 years. When the children were 3, 4 and 5 years old, their caries and gingival status were recorded. Streptococcus salivarius becomes established within a day of birth, and Streptococcus sanguis after the eruption of the teeth during the first year. Streptococcus mutans was recovered from the infants significantly later and had only become established in half the number of the infants when they had reached 5 years. Lactobacilli were only recovered in low numbers and below 2 years of age they seemed to be mostly transients in the mouth of the infants. The lactobacillus flora which was then isolated, was dominated by Lactobacillus casei and the composition of the flora was significantly different from that which has previously been described for adults.

ISSN:0008-6568    

DOI:10.1159/000260166

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Fresh carious and non-carious human dentine was crushed and the α-aminoacylpeptide hydrolase activity (EC 3.4.11) was quantitatively measured using N-L-aminoacyl-2-napthylamines of various amino acids as substrates. The activity per milligram protein in the sample in carious dentine was observed to be at least ten times higher than in non-carious coronal dentine. The difference was more pronounced (up to 500 times) when the rates of hydrolysis were calculated per milligram specimen. Active carious lesion revealed higher enzyme activity than arrested lesions, which difference was statistically significant. The values of arrested and residual carious lesions were on the level of those with fully formed root dentine. The values obtained from root dentine were about 5–10 times higher than in coronal dentine in living teeth. The rates of hydrolysis of the substrates catalyzed by enzymes from root dentine of teeth with gangrenous pulp or root-filled pulp chamber were nil or neglible. No significant difference could be demonstrated between permanent and deciduous teeth. The origin of these enzymes is thought to be the cellular components of the tissue while the more pronounced hydrolysis with carious dentine was thought to be microbi

ISSN:0008-6568    

DOI:10.1159/000260167

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

In a 2-year study of the calcium and phosphorus levels of mature plaque collected from male subjects aged 11–12 years at the commencement of the study, the plaque calcium and phosphorus levels were inversely related to both the new DMFS developing during the 2-year period and the total caries experience of the subjects at the end of the stud

ISSN:0008-6568    

DOI:10.1159/000260168

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The purpose of this study was to compare the F–– acquisition of enamel of APF solutions, NH4F containing solutions, organic fluoride solutions and a urethane lacquer-containing silane fluoride. The F–– content as a function of the distance from the anatomical surface was studied after one application, after 24 h of washing in tap water and after 1 week of washing. The results indicate that one treatment with the F–– containing lacquer introduces an amount of permanently deposited fluoride comparable to that of a great number of applications by the other solutions mentioned. The silane fluoride-containing lacquer introduces about 2,000 ppm of permanently bonded F–– in an average surface of

ISSN:0008-6568    

DOI:10.1159/000260178

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

This study has shown that the exposure of human dental enamel to acid solutions in vitro produces three basic etching patterns. In the most common, called type 1 etching pattern, prism core material was preferentially removed leaving the prism peripheres relatively intact. In the second, type 2 etching pattern, the reverse pattern was observed. The peripheral regions of prisms were removed preferentially, leaving prism cores remaining relatively unaffected. In the type 3 etching pattern, there was a more random pattern, areas of which corresponded to types 1 and 2 damage together with regions in which the pattern of etching could not be related to prism morphology. These findings differ from previous studies in which the type 1 pattern was ascribed to acid action and type 2 etching pattern to attack by chelators. The results therefore suggest that there is no one specific etching pattern produced in human dental enamel by the action of acid solutions. Such differences produced by acids are difficult to explain on the basis of variation in chemical composition, and crystallite orientation. This further highlights the variation in structure that can occur in enamel not only from tooth to tooth, or surface to surface, but also from site to site on a single tooth surface.

ISSN:0008-6568    

DOI:10.1159/000260179

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The purpose of this study was to investigate the ultra structural changes in human enamel – untreated and pre-treated with Na2FPO3 – after an artificial carious attack. With the scanning electronmicroscope the influence of local fluoride application on surface topography and on the caries lesions in cross-sections was investigated. The results show that in Na2FPO3 pre-treated specimen the prism core dissolved faster than the interprismatic areas. The experiments indicated forthermore that most likely FPO32–– ions influence both transport of ions in the lesion and in the surface layer; FPO32–– application caused a considerable ‘clogging’ of the interprismatic areas. A preparation method is outlined by which a detailed comparison of pre-treated and untreated enamel originally located less than 0.25 mm ap

ISSN:0008-6568    

DOI:10.1159/000260180

出版商:S. Karger AG    

年代:1975

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000260181

出版商:S. Karger AG    

年代:1975

数据来源: Karger