摘要:

Plasma fluoride (F) concentration and urinary output of F were studied in 4 children, 4, 5, 12 and 14 years of age, after oral application of a F-containing varnish (Duraphat®). The F dose was found to be 2.3–3.0 mg for the younger children and 5.0–5.2 mg for the older ones. The highest plasma F concentration varied between 60 and 120 ng F/ml and was seen within 2 h of treatment. The urinary output of F during 12 h after varnish application was about 550 μg F/12 h for the younger children and 1,100 μg for the older ones. The plasma levels found are far below those considered

ISSN:0008-6568    

DOI:10.1159/000260452

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

In this paper the relation between the average lesion depth (1) of artificial carious lesions and the length of microhardness indentations (D) on the surface (the load perpendicular to the surface) is investigated. The results show that an empirical linear relationship does exist between 1 and D for both human and bovine enamel. Linearity has been found for decalcification periods 2–8 days and pH values 4.5 and 4.0. The slope of the curves as well as the load dependency is discussed. The error in the lesion depth determinations is 10–15%. The study also gives a numerical comparison between the average lesion depth in human and in bovine enamel decalcified under the same conditions. After 4 days at pH 4.5 or 4.0, the relations are 1 (bovine) ≈ 1.4 # 1(human) and 1 (bovine) ≈ 1 (human), respectively. The advantage of the technique presented here is that is does not destroy the specimen and is suitable for experiments in in vivo sit

ISSN:0008-6568    

DOI:10.1159/000260453

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The aim of the present study was to investigate the influence of surface enamel on the susceptibility of the tissue to acid attack by exposing both unabraded and abraded surfaces to an identical artificial caries system. Enamel from teeth developed in ‘low’, ‘optimal’ and ‘high’ fluoride areas was used for the experiment and the fluoride content of the surface enamel under test was sampled. Results confirmed the protective nature of surface enamel and the resistance of the fluorosed tissue to the artificial caries process. However, no difference was found between enamel from low and optimal fluoride areas in either the fluoride content of the surface enamel or its susceptibility to acid attack. It is, therefore, suggested that the cariostatic effect of fluoride in optimal fluoride areas may well be a result of its top

ISSN:0008-6568    

DOI:10.1159/000260454

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

This paper describes a method for measuring calcium and phosphorus levels in very small samples of dissolved enamel. The technique is an extension of a method first used by von der Fehr and Steinnes and involves irradiation of the enamel samples by thermal neutrons, the amounts of calcium and phosphorus present being calculated from measurements of the radio-isotope produced. The results obtained showed considerable variation, from 9–180 ng for phosphorus and 13–510 ng for calc

ISSN:0008-6568    

DOI:10.1159/000260455

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Demineralization of enamel by acid buffer and the use of protective agents to combat it were studied by two different techniques, one using intact enamel surfaces and the other powdered enamel. Compared with the acknowledged protective effect of fluoride, calcium glycerophosphate was the most effective phosphate compound. Sodium phytate and calcium sucrose phosphate gave less consistent results. Applied topically, α-glycerophosphate was more effective than β-glycerophosphate. Pretreating the enamel with saliva or a protein solution improved its resistance to the attack of acid buffer but reduced the apparent effectiveness of the protective agent

ISSN:0008-6568    

DOI:10.1159/000260456

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Apparatus and techniques were evolved for a sensitive and reproducible test measuring the demineralization by acid of hydroxylapatite or powdered enamel as the stationary phase in high-performance liquid chromatography columns. Demineralization was quantified by monitoring the column eluate for UV absorbance and integration of the area of the UV peaks, with concomitant serial calcium analyses. Treating the hydroxylapatite with sodium fluoride conferred relatively long-acting protection against demineralization. The main effect of the fluoride appeared to be in reducing the acid solubility of the outer layers of the hydroxylapatite. Contrary to earlier theories that the protective action of calcium glycerophosphate was exerted only in the media surrounding the teeth, this agent was found to interact directly with hydroxylapatite, reducing the extent of demineralization by an average of 50%. The UV and the calcium analysis data showed how the mechanisms of protection by glycerophosphates and fluoride differed.

ISSN:0008-6568    

DOI:10.1159/000260457

出版商:S. Karger AG    

年代:1980

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000260458

出版商:S. Karger AG    

年代:1980

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000260459

出版商:S. Karger AG    

年代:1980

数据来源: Karger