摘要:

The action of sodium monofluorophosphate on Syntheti chydroxyapatites has been studied using pure mono- syntheticfluorophosphate solutions.Monofluorophosphate-treated hydroxyapatite was less soluble in acid buffer than fluoride-treated mineral of similar fluorine content. During the reaction some orthophosphate was liberated from the solid and addition of orthophosphate to the monofluorophosphate inhibited subsequent uptake of fluorine by the hydroxyapatite. The FPO3 anion was present in the treated hydroxyapatite and was shown to have replaced the hydrogen phosphate group of the calcium-deficient hydroxyapatites. In this way the capacity of a calcium-deficient hydroxyapatite for uptake of monofluorophosphate was related to its HPO4 content; i.e. its Ca:P molar ratio. Replacement of the acid phosphate groups of the hydroxyapatite, either by FPO3 substitution or by thermal condensation to pyrophosphate reduced the isotopic exchange of orthophosphate by the mineral.

ISSN:0008-6568    

DOI:10.1159/000259766

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Caries was produced around class V fillings in human teeth in situ. The material consisted of 44 teeth, including 13 controls. The teeth were scheduled for extraction for orthodontic or prosthodontic reasons and the experimental period ranged from 21 to 180 days. Age of the patients ranged from 11 to 62 years. For the production of caries a preformed orthodontic band was attached to the teeth in order to induce accumulation of plaque material. Following extraction, ground sections were prepared and studied mainly by polarized light microscopy and microradiography. The pathogenesis of observed in vivo lesions was found to correspond to that of the in vitro lesions around fillings described by Hals and Nernaes [1971]. The ‘cavity wall lesion’ was seen in 11 out of 28 experimental cases. In experiments with a duration of 100 days or more, the subsurface demineralization of the ‘outer lesion’ was often followed by a secondary surface demineralization. The positively birefringent zone of enamel caries, seen when examined in quinoline, was common and was observed as early as after 21 days. In dentinal tubules ending at the cavity wall, bodies supposed to be ‘caries crystals’ were observed

ISSN:0008-6568    

DOI:10.1159/000259767

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Whole tooth crowns of rats, labelled with 32P, were incubated in buffer solutions in the presence of caries-inducing K-1 streptococci of human origin. The changes associated with sucrose fermentation were: decreased extra- cellular ρH, increased phosphorus release from the teeth, increased phophorus content and a markedly increased 32P label of the organisms. An addition of Na2HPO4 to the fermenting system, whilst increasing the cellular total phosphorus content further, reduced the cellular P label. When used in high quantity, the Na2HPO4 also prevented pH drop and lessened the 32P release from the teeth. The transfer of 32P from the teeth into the cariogenic bacteria was reduced by addition of Na2HPO4

ISSN:0008-6568    

DOI:10.1159/000259768

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

In extension of previous experiments, a study was devised to test the effect on caries activity of adding calcium glycerophosphate to the diet of monkeys. Five experimental and 6 control animals were fed a high carbohydrate diet. Both groups of animals received icing sugar 5 times daily but that fed to the experimental animals contained 1% calcium glycerophosphate. After 30 months it was observed that the control animals had 47 carious lesions and the experimental animals 8 (p < 0.01). All the control animals developed dental caries, whereas 3 of the experimental animals remained caries-free. Higher levels of calcium, and lower concentrations of soluble and insoluble carbohydrate were observed in the plaque of experimental animals than in plaque of the control monkeys. No differences were observed in the protein and total phosphate content. Both the fasting pH values of plaque and those observed 20 min after the application of sucrose were higher in the experimental animals. Slightly higher counts of micro-organisms were found in plaque from the experimental animals.

ISSN:0008-6568    

DOI:10.1159/000259769

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Spray-dried glucose syrup was compared with sucrose at a level of 66% in the diets of laboratory rats. In two 8-week experiments with a total of 86 rats of two separate strains, the difference in mean caries scores between the glucose syrup and sucrose groups was not significant. The influence of physical consistency was investigated by comparing diets containing 46% glucose syrup (dry weight) either as a spray-dried powder or in its original viscous liquid form. Using 53 rats over periods of 5 or 8 weeks, no significant differences were detected between the mean caries scores on the two diets. More than 98% of the carious lesions were in the molar fissures.

ISSN:0008-6568    

DOI:10.1159/000259770

出版商:S. Karger AG    

年代:1972

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000259771

出版商:S. Karger AG    

年代:1972

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000259772

出版商:S. Karger AG    

年代:1972

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000259773

出版商:S. Karger AG    

年代:1972

数据来源: Karger